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IDENTIFICATION AND UNDERSTANDING OF FACTORS AFFECTING PERFORMANCE OF DAIRY CATTLE IN HEAT STRESS CONDITIONS A THESIS SUBMITTED TO THE GRADUATE DIVISI...

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IDENTIFICATION AND UNDERSTANDING OF FACTORS AFFECTING PERFORMANCE OF DAIRY CATTLE IN HEAT STRESS CONDITIONS

A THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI'I AT MANOA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTERS OF SCIENCE IN ANIMAL SCIENCE DECEMBER 2004

By Noniponimo'i Keala

Thesis Committee: Chin N. Lee, Chairperson James R. Carpenter Douglas L. Vincent

ACKNOWLEDGMENTS

I would like to acknowledge my major advisor, Dr. Chin Lee, for providing guidance, support, and understanding throughout the process of obtaining my Master's degree. I would also like to express sincere gratitude to Dr. James Carpenter for his knowledgeable teaching and assistance; to Dr. Douglas Vincent for his enlightenment on fundamental issues; to Wayne Toma for his time, effort and support in helping me get through all the statistical analyses; to my partner in crime, Michelle Watson, for always taking care of me and being my knight in shining armor; to Barbie Lee for her patience, help and understanding; to my fellow church members for guidance and prayer; to the Moore family for their support and hospitality; to the Department of Human Nutrition, Food and Animal Sciences for providing a knowledgeable environment in which to learn; to my friends for standing by my side through thick and thin, no matter what the circumstance; and a sincere mahalo to Monique Vanderstorm and Robin Dewalo of Pacific Dairy Inc., David Wong of Mountain View Dairy, and David Kugger of Evergreen Dairy for the use of their cows and facilities for my experimental trials. For my family, I would like to acknowledge and thank them for their love, support and guidance throughout the years to help fulfill me intellectually and attain my goals. Thanks to the Keala family on Maui for providing me with a loving foundation of family; to my dad for support and my brother Mano for his eccentricity and brotherly love; and to Sharon for her support, guidance and understanding that helped me to become a stronger person. I appreciate all of their contributions to my education and personal growth.

111

Finally, I would like to dedicate my thesis with love to my mom Claudette Vanna for her loving ways and determination that have helped to mold me into the person I am today, and to the Lord, who proclaimed that "Verily, verily, I say unto you, Whatsoever ye shall ask the Father in my name, he will give it." (John 16:23); "0 give thanks unto the Lord; for he is good." (Psalm 118:1).

lV

TABLE OF CONTENTS

ACKNOWLEDGEMENTS

iii-iv

ABSTRACT

vii

LIST OF FIGURES

viii-xi

LIST OF ABBREVIATIONS AND SYMBOLS

xii-xiii

CHAPTER 1: LITERATURE REVIEW

1.1 STRESS 1.1.1

Definition of stress

1

1.1.2 Mechanism of stress 1.1.3

:

.2

Heat stress

3

1.1.3.1 Reproduction

7

1.1.3.2 Nutrition

9

1.1.3.3 Hair Coat Color

11

1.2 METHODS TO RELIEVE HEAT STRESS 1.2.1

Mechanical Refrigeration and Cooling Ponds/Pads

13

1.2.2

Shade systems

14

1.2.3

Mechanical Ventilation

19

1.2.4 Evaporative Cooling Systems

21

CHAPTER 2: EFFECTS OF HEAT STRESS ON DAIRY CATTLE USING DIFFERENT COOLING SYSTEMS: MONITORING RESPIRATION RATES, SKIN TEMPERATURES, RECTAL TEMPERATURES, 305 DAYS MILK PRODUCITON AND TEMPERATURE HUMIDITY INDEX

2.1 INTRODUCTION

25

2.2 MATERIALS AND METHODS

v

,

"

.26

2.2.1

Experiment 1

29

2.2.2

Experiment 2

30

2.2.3

Experiment3

"

,

,

31

2.3 STATISTICAL ANALYSIS

32

2.4 RESULTS AND DISCUSSION

32

2.4.1

Experiment 1

32

2.4.1.1 Respiration Rates

32

2.4.1.2 Milk Production

39

2.4.1.3 Temperature Humidity Index 2.4.2

2.4.3

Experiment 2

.41 43

2.4.2.1 Skin and Rectal Temperatures

.43

2.4.2.2 Milk Production

,

.46

2.4.2.3 Temperature Humidity Index

.47

2.4.2.4 Sprinkler Systems

.48

Experiment 3

,

2.4.3.1 Skin and Rectal Temperatures

50 50

CHAPTER 3: SUMMARY AND CONCLUSION

3.1 SUMMARY AND CONCLUSION

99

3.1.1

Experiment 1

99

3.1.2

Experiment 2

100

3.1.3

Experiment 3

101

APPENDIX A - DAIRY A, B, & C LAYOUT PHOTOGRAPHS LITERATURE CITED

103-106 107

VI

ABSTRACT

A summer (September-October) of 2002 and winter (February-March) of 2003 study evaluated different cooling systems by observing responses of Friesian Holstein cows located in Waianae, Honolulu, Hawaii. Treatment pens for experiment 1-3 were designated as: [Dairy A = Pens with Zinc Corrugated Shade Structures (SI, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C

=

36-inch Schaffer Fans under Aluminum Shade Structure (SF);

Misting System under Aluminum Shade Structure (SM)]. Parameters that were measured included respiration rates, skin temperatures, rectal temperatures, 305 days estimated milk production and temperature humidity index. The most effective cooling system during experiment I trials was pen SK, which was followed by pen UOF, then pen SM, pen SF and lastly, the pens Sl, S2, S3 and 54. The most effective cooling system during experiment 2 trials was pen SK and pen SM, which was followed by pen UOF, and NS. During experiment 3, differences were observed between the (1 sl 20 vs. 2nd 20 animal readings), (wet vs. dry hair coat animals), (Am vs. PM) and (Hair Coat Color). The combined results of this study indicated the importance and usefulness of cooling systems to aid in increasing productivity and overall comfort in lactating Holstein dairy cows under heat stress conditions in Hawaii. Keywords: Heat Stress, Dairy Cows, Cooling systems.

VB

LIST OF FIGURES

Figure

1.

Page

Respiration rates of lactating Holstein dairy cows exposed to cooling systems between dairies across seasons in the subtropics

58

Respiration rates of lactating Holstein dairy cows exposed to cooling systems between seasons within dairies in the subtropics

58

3A. Respiration rates of lactating Holstein dairy cows exposed to cooling systems between pens summer seasons in the subtropics

60

3B. Respiration rates of lactating Holstein dairy cows exposed to cooling systems between pens winter seasons in the subtropics

60

2.

4.

Respiration rates of lactating Holstein dairy cows exposed to cooling systems between times of day (AM vs. PM) across seasons in the subtropics....62

5.

Respiration rates of lactating Holstein dairy cows exposed to cooling systems between times of day (AM vs. PM) across seasons within dairies in the subtropics

62

6A. Respiration rates oflactating Holstein dairy cows exposed to cooling systems between pens within times of day (AM) across seasons within dairies in the subtropics 64 6B. Respiration rates oflactating Holstein dairy cows exposed to cooling systems between pens within times of day (PM) across seasons within dairies in the subtropics 64 7.

The 305 days estimated milk production oflactating Holstein dairy cows exposed to cooling systems between dairies across seasons in the subtropics .....66

8.

The 305 days estimated milk production of lactating Holstein dairy cows exposed to cooling systems between seasons within dairies in the subtropics.....66

9A. The 305 days estimated milk production oflactating Holstein dairy cows exposed to cooling systems between pens within seasons across dairies in the subtropics

68

9B. The 305 days estimated milk production oflactating Holstein dairy cows exposed to cooling systems between pens within seasons across dairies in the subtropics

68

Vlll

10.

11.

12.

13.

14.

Temperature Humidity Index of dairy housing within dairies across seasons in the subtropics

70

Temperature Humidity Index of dairy housing within summer seasons within dairies in the subtropics

70

Temperature Humidity Index of dairy housing within winter seasons within dairies in the subtropics

72

Skin temperatures of lactating Holstein dairy cows exposed to cooling systems between pens within seasons across dairies in the subtropics

74

Rectal temperatures of lactating Holstein dairy cows exposed to cooling systems between pens within seasons across dairies in the subtropics

74

15.

Skin temperatures of lactating Holstein dairy cows exposed to cooling systems between pens within times of day (AM vs. PM) across seasons across dairies in the subtropics 76

16.

Rectal temperatures of lactating Holstein dairy cows exposed to cooling systems between pens within times of day (AM vs. PM) across seasons across dairies in the subtropics 76

17. The 305 days estimated milk production of lactating Holstein dairy cows exposed to cooling systems between dairies across seasons in the subtropics .....78 18.

The 305 days estimated milk production of lactating Holstein dairy cows exposed to cooling systems between seasons within dairies in the subtropics .....78

19.

The 305 days estimated milk production oflactating Holstein dairy cows exposed to cooling systems between pens within seasons across dairies in the subtropics

80

Temperature Humidity Index of dairy housing within dairies across seasons in the subtropics

80

Temperature Humidity Index of dairy housing within seasons within dairies in the subtropics

82

Skin temperatures oflactating Holstein dairy cows exposed to cooling systems with sprinklers (Offvs. On) for pens in dairy B during the summer in the subtropics

82

20.

21.

22.

23.

Rectal temperatures (RT) of lactating Holstein dairy cows exposed to cooling systems with sprinklers (Off vs. On) for pens in dairy B during the summer in the subtropics 84

IX

24.

Skin and rectal temperatures of lactating Holstein dairy cows exposed to Saudi Korral Kool Barn with galvanize shade structure cooling system for pen (SK) in dairy B between conditions (1 st 20 vs. 2nd 20 animal readings) 86 during the winter in the subtropics

25.

Skin and rectal temperatures of lactating Holstein dairy cows exposed to no shade structure over the feed manger for pen (UOF) in dairy B between conditions (1 st 20 vs. 2nd 20 animal readings) during the winter in the subtropics

86

Skin and rectal temperatures oflactating Holstein dairy cows exposed to no Shade structure over the feed manger for pen (NS) in dairy B between Conditions (1 st 20 vs. 2nd 20 animal readings) during the winter in the subtropics

88

Skin and rectal temperatures of lactating Holstein dairy cows exposed to a Misting cooling system under aluminum shade structure (SM) in dairy C between conditions (Dry vs. Wet hair coat animal readings) during the winter in the subtropics

88

26.

27.

28.

Skin and rectal temperature of lactating Holstein dairy cows between times (AM vs. PM) for pen SK in dairy B across seasons in the subtropics....... 90

29.

Skin and rectal temperature of lactating Holstein dairy cows between times (AM vs. PM) for pen SM in dairy C across seasons in the subtropics

90

Skin and rectal temperature of lactating Holstein dairy cows between times (AM vs. PM) for pen UOF and NS in dairy B across seasons in the subtropics

92

Skin temperature of "Black Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics

92

Rectal temperature of "Black Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics

94

Skin temperature of "Black/White Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics

94

30.

31.

32.

33.

34.

Rectal temperature of "Black/White Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics 96

35.

Skin temperature of "White Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics

x

96

36.

Rectal temperature of "White Hair Coat Color" lactating Holstein dairy cows exposed to cooling systems within seasons within dairies in the subtropics

Xl

98

LIST OF ABBREVIATIONS AND SYMBOLS

°C

Celsius

cm

centimeters

cfin

cubic feet per minute

db

dry bulb temperature

DRI

dairy herd improvement

DIM

days in milk

OF

Fahrenheit

ft

feet

hp

horse power

III

inch

kg

kilogram

km

kilometer

kW

kilowatt

lb

pound

m

meters

p

probability

pSI

pounds per square inch

RR

respiration rates

RT

rectal temperatures

rh

relative humidity

s

second

Xll

ST

skin temperatures

sq ft

square feet

THI

temperature humidity index

TNZ

thermal neutral zone

x

multiplication symbol

Dairy A

[Pens with Zinc Corrugated Shade Structures (S 1, S2, S3, S4)]

DairyB

[Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10feet away (UOF); No Shade Structure over the Feed Manger (NS)]

Dairy C

[36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]

X1l1

CHAPTER 1

LITERATURE REVIEW

1.1 STRESS 1.1.1

DEFINITION OF STRESS Hans Selye fonnulated the tenn "stress" as "the sum of all nonspecific responses

of the body to any demand on it or any nonspecific changes caused by function or damage" (Selye, 1978). "Stress" in general can be due to any stressor that threatens the animal's homeostasis of the body. Stressors may include external bodily forces that alter the homeostasis mechanism of the animal's body, combined with the "strain" which is the internal alteration from the homeostasis mechanism that is brought about by stress (Lee, 1965; Stott, 1981). Homeostasis signifies a constant state of vital ability while sustaining function within nonnal ranges of variation with respect to various factors such as species, breeds, population, ages, body sizes, physiological and productive status, acclimatization, feed consumed, activity of the animal and the option for cooling systems (Franson and Spurgeon, 1992). Stress factors may be climatic, such as extreme heat or cold, high humid environments and drafty windy areas; nutritional, due to poor quality or inadequate feed and water; social, such as hierarchy or dominance due to the rank in pecking order; physical, such as handling/processing or illness or injury; inappropriate facilities, such as insufficient ventilation which can lead to excessive gas build up and dust, overcrowding or inappropriate stocking densities, which can lead to fighting and disease transmission; internal, due to some physiological disorder, pathogens or toxins

1

(Stott, 1981). Readjusting to the homeostasis mechanism or acclimating to any situation is vital for the survival and well-being of the animal.

1.1.2

MECHANISM OF STRESS The two basic stress response mechanism theories are Cannon's Emergency

Syndrome or Alarm Reaction (1932), which includes the sympatho-adrenal system and Selye's (GAS) General Adaptation Syndrome (1955), which is composed of the hypophyseal-adrenal axis (Stott, 1981).

Cannon's theory was based on the body's

response to stressful stimuli, which is also known as the "fight or flight" reaction. Stimuli could be triggered by conditions of danger or exposure to environmental extremes. Selye's (GAS) theory occurs when animals are exposed to gradual or prolonged stressors. The three phases of GAS are the alarm phase, the resistance phase, and the exhaustion phase. The dominant hormone in the alarm, or "fight or flight" phase is epinephrine, which is released as an immediate short-term response to stressors. This release of epinephrine results in the mobilization of energy reserves in the form of glucose (Martini, 1998). Martini said "the characteristics of the alarm phase include increased mental alertness, increased energy consumption by skeletal muscles and other peripheral tissues, the mobilization of energy reserves like glycogen and lipids, increased blood flows to skeletal muscles, decreased blood flow to the skin, kidneys, and digestive organs, a drastic reduction in digestion and urine production, increased sweat gland secretion and increased blood pressure, heart rate and respiratory rate." The resistance phase begins when stressors last longer than a few hours, days or weeks and cause metabolic adjustments with glucocorticoids as the dominant hormone. 2

During the resistance phase, endocrine secretions are released to the remaining energy reserve, conservation of glucose occurs for neutral tissues, followed by elevated blood glucose concentrations, and conservation of salts and water that prevents losses of K+ and H+ (Martini, 1998). The resistance phase is followed by the exhaustion phase during which factors such as poor nutrition, emotional or physical trauma, chronic illness, or damage to key organs such as the heart, liver, or kidneys occur (Martini, 1998). Martini stated that "the exhaustion phase begins when the vital systems start to collapse due to the exhaustion of lipid reserves, the inability to produce glucocorticoids, accompanied by failure of electrolyte balance and long-term structural or functional damage to vital organs. Corrective actions should be taken immediately to prevent the failure of one or more organ systems that can be fatal." Hence, during periods of acute heat stress conditions, hormonal changes include increased concentrations of epinephrine and norepinephrine in the blood. During chronic or severe heat stress conditions, alterations include decreased concentrations of thyroxin, growth hormone, aldosterone, and glucocorticoids that ultimately lead to decreased basal metabolic rates and milk production (Thompson et al., 1999). Thus stress or stress factors can hinder productivity of animals. 1.1.3

HEAT STRESS

One of the most important factors in raising livestock during the summer and in tropical areas is heat stress. In general, heat stress can be defined as a combination of environmental circumstances that cause the effective temperature of the environment to rise above the animals Thermal Neutral Zone (TNZ) or comfort zone (Bufffington et aI., 1981; Shultz, 1984; Bucklin et al., 1991; Armstrong, 1994).

3

Optimal animal

perfonnance can be obtained within the TNZ temperature range. The average upper critical air temperature for lactating cows range from 24-27°C or 75-80°F (Fuquay, 1981).Failure of animals to adapt or return to nonnal homeostasis during periods of heat stress can reduce productivity and eventually lead to death (Blackshaw and Blackshaw, 1994). The most common comfort index used to measure environmental parameters of animals is the Temperature Humidity Index (THI). The THI equation is: [THI (0.55 - 0.55rh) (Tdb

-

=

Tdb

-

58)] which includes the dry bulb temperature (db, OF) and relative

humidity (rh) (National Academy of Sciences, 1971; West, 1999). Research has shown that when the THI exceeds 72, dairy cows are affected adversely (Buffington et al., 1981; Igono et al., 1992; Annstrong, 1994; Brouk et al., 1999). Zahner et at. (2004) reported a significant positive correlation between THI and body surface temperatures, rectal temperatures and cortisol concentrations in milk during heat stress conditions. Brouk et al. (1999) reported dry matter intake decreased by 1.73 kg per/cow/day and milk

production decreased by 4 kg per/cow/day when THI values increased from 68 to 78. The regression equation during this study indicated milk yield tends to drop by 0.41 kg per/cow/day for each point that increases above 69.

Ingraham et al. (1976) reported that

conception rate decreased from 66% to 35% as the temperature humidity index increased from 65 to 78°C. Bouraoui et al. (2002) reported milk production decreased by 21 % and dry matter intake decreased by 9.6% when the THI values increased from 68 to 78. In this study the THI was positively correlated to respiration rates (r=0.89), heart rate (r=0.88), rectal temperatures (r=0.85) and cortisol (0.31), and negatively with free thyroxin (-0.43).

4

The four main environmental factors that influence effective temperature are: 1) air temperature, 2) relative humidity, 3) air movement, and 4) radiation from the sun or other sources (Gwazdauskas, 1985; Turner and Bucklin, 1990; Bucklin et aI., 1991; Armstrong, 1994). The animal's environment includes four basic heat exchange processes: conduction, convection, radiation and evaporation. Conduction refers to the transmission of energy, heat or sound through physical contact or heat flowing from warm to cold objects. This occurs when animals swim in a pool or pond or lie on cold concrete floor surfaces. Convection occurs as the layer of air in immediate contact with the skin is replaced by cooler surrounding air or the transfer of heat by the movement of air, gas or heated liquid between areas of unequal density, for example, warm air rising because it is lighter than cool air. Animals gain heat from convection or conduction only if the air temperature is higher than the animal's skin temperature or if the animal is resting against a surface hotter than its skin. Heat loss in animals occurs through the elimination of by-products of metabolism, which include feces, urine and milk. Radiation is the process in which radiant energy is distributed in the form of particles or waves of light. Radiation may be influenced by body surface area, skin temperature, air surrounding the animal and the ability of the animal's skin to absorb and emit heat. Radiant heat loss occurs when the ambient temperature is significantly cooler than the cow.

Evaporation occurs when water is converted from a liquid into a vapor.

Evaporative heat in animals is an important factor in high ambient temperatures and can result in increased respiration rates during periods of heat stress (Fuquay, 1981). Evaporative heat loss occurs when the dew point temperature around the animal is lower than the temperature of the animal's evaporative surface. However, high humidity and

5

clouds have shown to restrict radiant and evaporative cooling.

The major signs of

advanced heat stress include open-mouth breathing with head extended or pointing, increased respiration rates, increased dorsal skin and rectal temperatures and profuse salivation. Dairy cows may respond to heat stress in any of the following ways: 1) reduced feed consumption and frequency of eating activity during the day (Brown-Brandl et al., 2003; Podmanicky et al., 2002; West et al., 2002); 2) increased water consumption

(Brown-Brandl et al., 2003); 3) changed metabolic rate and maintenance requirements; 4) increased evaporative water loss; 5) increased respiration rate; 6) changed blood hormone concentrations; 7) increased body temperature; 8) increased rectal temperatures; 9) decreased milk production (Johnson, 1987; Turner, 1998; Podmanicky et at., 2002; West et al., 2002) and negative cheese-making qualities (Cappa et al., 1989; Calamari and

Mariani, 1998; Vazhapilly et al., 1992); 10) increased somatic cell count (Paape et al., 1973; Rodriquez et al.,

1985; Nickerson, 1987); 11) decreased reproductive

efficiency/performance (Ingraham et al., 1974; Roman-Ponce et al., 1976; Fuquay, 1981; Hahn, 1985; Johnson, 1987; Bucklin et al., 1991; Shearer et al., 1991; Armstrong, 1994; Turner, 1998); 12) altered endocrine functions (Gwazdauskas, 1985; Lee et al., 1994); 13) lowered immune defenses (Bertoni, 1998) and 14) increased standing time to maximize evaporation from body surfaces (Igono et al., 1987; Brown-Brandl et al., 2003) or movement to a shaded area. A dairy cows responses to heat stress may vary due to breed, size of animal, level of production or physiological state, present and previous weather, length of stress period, prior conditioning, compensatory growth, and relative levels of environmental factors, level of response or adaptability and health status (Fuquay, 1981; Barth, 1982; Turner and Bucklin, 1990). The higher the production

6

levels of animals the more adversely affected are the animals' milk production, reproductive performance and overall health (Johnson, 1987; Armstrong, 1994). Preventing and reducing heat stress and providing a suitable condition for animals may be accomplished by following three basic management schemes: 1) providing physical modifications to the environment, such as shade and cooling systems; 2) enhancing genetic development to produce breeds that are less sensitive to heat, and 3) implementing improved nutritional management methods (Beede and Collier, 1986; Kurihara and Shioya, 2003). 1.1.3.1

REPRODUCTION

Reproductive losses associated with heat stress have been well-documented and also have shown to be economically significant factor for producers. Factors that affect reproductive efficiency include wind, humidity, herd density, social status, intraspecies integration, animal manipulation, transportation, alteration of routine, physiological distress, physical trauma, and temperature, hot or cold (Moberg, 1976). Heat stress affects the prepartum, peripartum and postpartum periods negatively. Normal gestation length in cattle may range from (270-292) days and can be divided into three periods most critical to heat stress which include the ovum, blastula or early embryo (from fertilization to days 10-12) the embryo and organogenesis (from days 10-45) and the last period of the fetus and fetal growth (from days 45 to parturition) (Shearer et al., 1991). The early embryonic development stage and last trimester stage are the most critical and sensitive periods to heat stress.

Effects of heat stress on reproductive performance

includes: 1) altering the length and expression of the estrous cycle (Lee, et al., 1994; 2) altering the length and intensity of estrus (Labhsetwar et al., 1963; Moberg, 1976;

7

Fuquay, 1981; Thatcher and Collier, 1985; Her et al., 1988; Shearer et al., 1991, 1999) which may result in anestrous or silent head during ovulation (Bond and McDowell, 1972; Her et aI., 1988; Alnimer, 2000); 3) endocrine alterations (Gwazdauskas, 1985; Lee et al., 1994; Alnimer, 2000); 4) reduced fertility (AI-Katanani et al.,2001; Rensis and Scaramuzzi, 2003) 5) reduced blood flow to the uterus and developing fetus which results in smaller calves at birth (Collier et aI., 1982b; Wolfenson et al., 1988; Shearer et al., 1999) 6) reduced placenta mass (Wolfenson et al., 1988; Armstrong, 1999); 7) reduced conception rates (Fallon,

1962; Ingraham,

1974; Roman-Ponce et al.,

1976;

Gwazdauskas, 1985; Shearer et aI., 1991, 1999; Rensis and Scaramuzzi, 2003); 8) increased early embryonic death (Thatcher and Collier, 1985; Shearer et al., 1999; Alnimer 2000); and 9) increased mastitis and impacts on milk quality (Shearer and Beede, 1990). In males, heat stress conditions cause depressed sperm concentrations, mobility and fertility, and libido (Mount, 1979).

Studies by Roman-Ponce (1976)

reported a conception rate based on total services was higher for shaded cows at (44.4%) 54 services compared to (25.3%) 75 services for no shade cows. Ryan and Boland (1992) reported cows under evaporative cooling systems had a significant increase in conception rate of (84%) 62 out of 75 compared to (60%) 44 out of 75 of cows under a spray and fan cooling system. Providing comfortable conditions for cattle during the reproductive processes can be achieved by minimizing heat stress and other stressful events.

This can include providing high quality forage and feed, and using cooling

systems and hormonal treatments that may help to restore normal fertility and maximize reproductive performance.

8

1.1.3.2 NUTRITION Another source of heat generation in the cow occurs through rumen fermentation and nutrient metabolism. When animals are exposed to high environmental temperatures, feed intake decreases. Studies have demonstrated that dry matter intake decreased when the temperature is above 24°C or 75°F (Chamberlain, 1989; Bucklin et al., 1992) or above the thermal comfort zone. Research revealed that cows under thermal neutral zone or comfortable conditions ate 25% more dry matter (15.1 vs. 11.1 kg/day) and produced about 3 kg/day more milk (19 vs. 16.2 kg/day) than cows in conditions above the normal thermal neutral zone range (McGuire et aI., 1989). Lowered feed intake results in slower rates of passage through the digestive system (Bernabucci et al., 1999) that ultimately results in decreased milk production. Some strategies that can be considered during hot weather conditions to help maintain dry matter intake include decreasing the forage to concentrate ratio, supplementing fat, elevating dietary protein, increasing water intake, and increasing dietary concentrates of potassium, sodium and magnesium, feeding buffers (Shearer et aI., 1991, 1999) and allowing the feeding of roughages and forages during the early morning or late nights (Chamberlain, 1989).

During hot weather

conditions the decreases in dry matter intake, results in reduced nutrient absorption, which ultimately leads to an excess of degradable dietary protein (West, 1999). Lee, (2003) recommends acid detergent fiber levels should be at least 18-19%, or the neutral detergent fiber should at least be between 25%-28% of the dietary dry matter intake. A key problem associated with decreased roughage to concentrate ratios

IS

digestive disturbances, particularly rumen acidosis that can lead to problems like laminitis.

In general, rumen acidosis can occur by feeding high-energy diets and

9

allowing slug feeding (animals eating fewer meals but more at each feeding sessions). Increasing the feeding frequency helps to maintain stable rumen fermentation and normal digestion.

Decreases in feeding frequency results in decreased volatile fatty acid

production and contribute to alterations in the acetate/propionate ratio which ultimately leads to poor milk production and quality, most notable a change in fat and protein proportions (Collier et al., 1982a; Thompson et al., 1999). Feeding roughages can result in increased heat production or metabolic heat increments, while feeding rations high in grain and low in fiber results in lower heat production. Animals should be fed highquality forages ad libitum instead of forages that have higher cell walls, crude fiber and lower soluble carbohydrates. Low-quality forages are high in cellulose and lignin that ultimately increases rumen heat fermentation and slows digestibility, nutrient uptake and rate of passage.

Feeding the right feed ingredients with low heat increments

(concentrates and fats), in comparison to forages that have a higher heat increment, is important to help minimize metabolic heat during heat stress conditions. Modifying an animal's diet in combination with modifying its environment through cooling systems can help maximize the animal's production levels and provide a comfortable environment during periods of heat stress. Another solution that should be considered to aid animals during heat stress conditions is providing enough drinking water and drinking space (Lee, 2003). Research has shown that water intake and drinking frequency increases during periods of heat stress (Perissinoto et al., 2003; Brown-Brandl et al., 2003). This is due to the profuse amount of sweating and respiratory losses during heat stress conditions. Sweating results in an alteration of the dietary needs for minerals such as potassium, sodium and chlorine. This dietary alteration affects the ability of the animals to return to

10

normal body temperatures and metabolic homeostasis (Lee, 2003).

Lee (2003)

recommends increasing potassium to 1.5%, sodium to 0.45-0.55%, magnesium to 0.350.45% of diet dry matter and to restrict chlorine content to less than 0.35%. Sweating helps animals to dissipate heat and return to thermoneutral comfort. Sweat is a form of evaporative cooling. Average drinking water requirements for dairy cows is about 3-4 lbs of water per every pound of milk produced (Perissinoto, et a/., 2003). Titto (1998) reported that water intake may increase as much as 50-100 liters during hot weather or heat stress conditions and Beede (1992) reported high-producing cows in general consume about 190 liters of water each day. Lee (2003) reported cows drank about 3 kg/day when temperatures were below 5°C, but drank about 7 kg/day at high temperatures. Providing adequate waterers and space for animals to drink can help to replace any fluid losses during these hot conditions and increase animal comfort. 1.1.3.3

HAIR COAT COLOR

The two species of cattle include Bas indicus (tropical breeds) and Bas taurus (European breeds). Bas indicus cattle tend to be better adapted to high temperatures and have a shorter, lighter, glossier coat that is less dense than Bas taurus (Chamberlain, 1989). Bas indicus have: 1) higher sweating rates, 2) higher resistance to certain disease

and parasites, 3) hair coats that tend to reflect rather than absorb sun rays, 4) pigmented skin that reduces the risk of sunburn and skin cancer, and 5) folded skin and larger ears that help in heat elimination due to greater surface area.

Bas indicus also tend to have

lower productivity levels and metabolic rates than the Bas taurus species (Mount, 1979; Chamberlain, 1989).

11

Holsteins, a breed of the Bas taurus species, are the world's most dominant milkproducing animals and are generally characterized by a black and white coat. Research by Finch et at. (1984); Goodwin et aI, (1997) suggests that dark-colored cows tend to absorb more radiation heat than light-colored cows and are also more likely to seek shade to help minimize heat stress and maintain normal body temperatures. Minimizing heat stress helps to lessen any physiological or behavioral alteration that can have an impact on production and reproduction. Research by Hansen (1990) in Florida reported cows with white coats had lower rectal temperatures and lower drops in milk production than black cows (3.3 kg or 7.3 Ibs - black hair coat vs. 1.5 kg or 3.3 Ibs - white hair coat). Goodwin et al. (1997) also reported white cows (black < 30%) produced significantly higher daily milk yields than (black cows> 60%) during calving in heat stress conditions. However, King et al. (1988) in Arizona found no difference in milk production between hair coat colors. Research by Hillman et at. (2001) found that cows with a white hair coat absorbed about 66% of the short wave radiation compared to 89% absorption for predominately black hair coat colors. Hillman et at. (2001) also found that when exposed to direct sunlight, rectal temperatures for predominantly black cows increased by 4.8°C (41°F) and skin temperatures increased by 1.3°C (34°F) when compared to predominantly white-colored cows, which had an increase of 0.7°C (33°F) for rectal temperatures and an increase of 0.8°C/hour (33°F/hour) for skin temperatures. These studies suggest that hair coat color could be considered an important factor when planning heat stress defense strategies since black cows tended to have a more negative impact from thermal radiation then white coat colored cows.

12

1.2 METHODS TO RELIEVE HEAT STRESS 1.2.1

MECHANICAL REFRIGERATION AND COOLING PONDS/PADS

Several studies on mechanical refrigeration or air conditioning systems have shown to increase milk production and reproductive efficiency (Johnston et at., 1966; Thatcher, 1974), and decrease respiration rates and rectal temperatures (Hahn, 1985; Igono, et at., 1987; Wiersma and Armstrong, 1988).

Research by Thatcher (1974)

reported an increase of 9.6% in 4% fat corrected milk with mechanical refrigeration, and Buffington et at. (1978) reported an increase of 9.4% in milk production and an 11-20% increase in fertility.

However, theses researchers conclude that air conditioning and

mechanical refrigeration cooling methods have proven effective in cooling dairy cows, but the high operating expenses cannot be economically justified; thus it is very impractical for cooling dairy cows commercially. Other types of cooling methods include zone cooling, cooling ponds, and fan and pad cooling systems. Zone cooling works by cooling a particular zone on the animal, such as the head or neck. The animal then breathes in the cool air, and dissipation occurs through the respiratory system to help eliminate the heat load. Canton et at. (1982) reported lowered respiration rates and rectal temperatures for dairy cows under zone cooling when temperatures were below 18°C or 64.4°F. The maintenance and design of cooling pond structures are major factors that need to be considered before implementing this type of cooling system. Cooling pond temperatures generally range from 24-30°C or 75-86°F, and cooling of animals usually occurs within 5-10 minutes after the animal enters the pond. Some concerns include increased incidences of mastitis and higher milking hygiene maintenance. Research by

13

Bray and Shearer (1988) reported an increase in mastitis and a negative effect on milk quality when animals were exposed to stagnant or natural ponds.

Other problems

associated with stagnant or natural ponds include possibly predisposing animals to infectious diseases such as leptospirosis or other toxicities (Shearer et al., 1999). However, Beede (1987) and Shearer (1987) reported that in Florida, cooling ponds reduced body temperature effectively and had shown no adverse effects on udder health with appropriate pond maintenance. Cooling ponds can be used to help alleviate heat stress but pond maintenance and design are critical factors that should be considered to help prevent these types of problems. Cooling pads cool the air entering the housing but tend to increase relative humidity. Cooling pads are usually made up of conjugated cardboard and a fan system that is incorporated to cool the surrounding air (Shearer et al., 1999). Wiersma and Stott, (1974) reported a 2 kg/day or 4.4 lb/day increase in milk production and normal reproductive efficiency (60%) using cooling pads in drier climates. Taylor et al. 1986 also reported that cooling pads reduced air temperature around the animals, while Bucklin et al. (1991) reported that cooling pads required higher maintenance, were too expensive and were not durable. 1.2.2

SHADE SYSTEMS Shade is one of the simplest and the most feasible environmental modifications

that can be used to help reduce thermal radiation on animals (Roman-Ponce et al., 1976; Spain and Spiers, 1998). Well-designed shade structures can provide a shield from thermal radiation, which in tum can increase milk production (Igono et al., 1987; Muller et al., 1994), reproductive efficiency and animal survival (Buffington et aI., 1981, 1983).

14

Considerations for shade structure design should include orientation (north to south, east to west), space per animal, floor height, ventilation, roof construction, feeding and watering facilities and appropriate waste management systems (Buffington et at., 1983; Bucklin et at., 1991; Shearer et at., 1999). Shade structures have shown to reduce radiant heat loads and intercept direct solar radiation by 30-50% per animal (Bond et at., 1967; Roman-Ponce et ai., 1976). Un-shaded animals experienced radiant heat loads greater than their metabolic heat production (Bond et ai., 1967). Roman-Ponce et ai. (1976) reported a 10-19% increase in milk production averaging (16.6 vs. 15.0 kg/cow/day or 37 vs. 33 lb/cow/day) for shaded animals compared with unshaded animals. Igono et at. (1987) reported that cows cooled with spray and fan systems under shade produced about 2 kg/cow/day or 4.4lb/cow/day more milk than cows in shade alone. Shade systems are effective in helping to reduce heat stress and thermal radiation but have little effect on air temperature or humidity (Buffington et at., 1983; Strickland et at., 1989). Types of shades include natural shade (trees), hay, wood, galvanized steel,

aluminum, and neoprene coated nylon or shade cloth. All shade materials have different traits and levels of effectiveness. Trees provide an excellent source of shade and are very effective blockers of solar radiation (Shearer et at., 1999). Studies have demonstrated that cows prefer trees rather than man-made structures (Shearer et ai., 1999). Important factors that should be considered include providing fencing around tree roots to prevent damaging or killing the tree, and rotation of paddocks to prevent mud holes that can lead to soil erosion or inappropriate loafing areas for animals.

Other potential problems

associated with trees include toxicity from animals eating the leaves or a possibility of trees being struck by lightning. Trees do generally allow for better air movement.

15

Cooling animals by shade systems can be more effective through providing appropriate structure height, floor material, orientation and space per cow, providing feed and water facilities under shade structures, painting or insulating roofs, and incorporating ventilation or cooling systems. Reflective roofs coatings and insulation have shown to help reduce thermal radiation from metal roofs shade structures (Igono et at., 1987; Bucklin et at" 1993; Muller et at., 1994). Studies done by Buffington et al. (1978) reported that insulated and uninsulated metal roofs helped to reduce thermal radiation from 57°-37°C or 135°-99°F.

Some problems associated with roof coatings and

insulation includes higher expenses and structures that may not be economically feasible. Also, roof construction is made less effective because of day-to-day weather, dirt accumulation, and birds or pests destroying and damaging the insulated layers. Flooring for pen facility should be located on a well-drained soil or have a mounded area. In order to prevent mud holes, floors should be cleaned or maintained daily with a tractor to help minimize wet areas (Bucklin et at., 1991; Shearer et al. 1999) and promote drier and cleaner surfaces for animals (Armstrong, 1994). Providing welldesigned floor structures can help to promote healthier claw health and decrease claw and leg problems that are usually associated with wet and dirty surfaces (George and Meyer, 2003). To provide firm footing concrete floors should be at least 10 em (4 in) thick with a smooth grooved finish (Bucklin et at., 1991, 1992; Shearer et at., 1999).

Rough

concrete floors can speed animals' foot wear by 20% with cows being culled 20% in the first three weeks of new resurfacing due to foot abrasion, cuts and lameness (Bray et al., 1994b). A concrete slope that is 1.5-2% will help to promote flushing and drainage, and is not too steep or strenuous on the animals (Buffington et at., 1983; Bucklin et at., 1991,

16

1992; Bray et at., 1992b; Shearer et at., 1999). To help prevent mastitis concrete slabs can be cleaned and maintained by incorporating flushing systems, using dump tanks and high pressure hoses, or scraping with a tractor to keep areas sanitary and clean (Buffington et at., 1983; Shearer et at., 1999). Some important factors that should be considered with concrete flooring include the availability of water for flushing systems, appropriate space for the facility and proper set up and maintenance of settling basins, liquid/solid separators and pumping systems (Shearer et at., 1999). Slabs should extend 2.4 m (8 ft) on the north side, 1.2 m (4 ft) on the south side and 6.1 m (20 ft) on the east and west sides if eave height is 3.7 m (12 ft) (Bucklin et at., 1991; Shearer et at., 1999). Hurnick (1981) and Gebremedhin et at. (1985) reported an animal's first preference is a soil based flooring, followed by deep bedded shredded bark or saw dust bedded stalls, followed by rubber mat stalls, followed by carpet stalls and lastly concrete stalls. Different materials require different degrees of maintenance. Shade orientations can be east to west or north to south.

Factors that can

influence orientation include location and weather such as temperature, humidity and wind speed and/or direction. Proper orientation therefore depends on the unique situation of each facility, there is no one correct answer. To achieve drier conditions under shade structures, a north to south orientation is recommended (Armstrong, 1994). During the morning and afternoon hours, north to south oriented shades keep barns 35-50% drier than east to west oriented shaded areas (Shearer et at., 1999). To achieve maximum shade per cow, an east to west orientation is recommended (Armstrong, 1994; Shearer et at., 1999). Studies done by Pefley (2001) reported an east to west orientation reduced

respiration rates more than a north to south orientation (60.5 vs. 66.9).

17

Free stall design factors that should be considered include providing appropriate dimensions (length, width, neck rail, brisket board, stall curb, stall bed height, stall base and stall bedding) (McFarland, 2003). Well designed free stall structures can help to provide comfortable clean areas in which animals can relax. Well managed structures promote better health and well-being and higher productivity of animals. Important factors that should be considered to allow maximum air movement under shade structures include shade height and width, sidewall openings, wind speed, roof slope, ridge size, the eave openings and incorporated ventilation systems (Shearer et aI., 1999). Natural air movement can occur under shade structures with air drafts moving

through structures with open sides and through thermal buoyancy such as the chimney effect. Heated air rises and flows toward the ridge opening (Bucklin et aI., 1991; Shearer et aI., 1999). Studies done by various researchers found that higher shade structures

increased air movement through building structures while lower shade structures decreased air movement through the building structures and increased thermal radiation on animals (Buffington et al., 1983). However, research has concluded that the greater the height of the structure the greater the expense and maintenance required. Shearer et al. (1999) found that "shade structures of 40 ft or less require a minimum eave height of

12 ft and structures wider than 40 ft should be at least 16ft or more."

They also

recommend "at least 50 ft of clearance between adjacent buildings or any other obstructions such as trees." They also propose that "gable roof should have at least a 4:12 (33%) slope but 6:12 (50%) is acceptable but very difficult to do repair work on and often leaks."

Shearer et at. (1999) suggests "ridge caps if desired should have a

minimum of 1 foot clearance between the cap and the roof peaks." Shearer et al. (1999)

18

also recommends "ridge opening size should be a minimum of 1 foot wide plus 2 in for each 10ft of structure width with addition of insulation directly beneath the roofing to help reduce solar radiation on the animals." Studies suggest that in hot, humid climates, the amount of space required per cow should be increased to help improve ventilation and air movement around animals. Bray (1994a) suggests 4.6 m2 or 50 sq ft of space per cows is needed under shade structures while Buffington et al. (1983) recommend 4.2 - 5.6 m2 or 45 - 60 sq ft of shade per cow in hot humid conditions. Factors that should be considered include climate and available land and the type of shade structure. Feeding and water facilities also should be located under shade structures to promote ad libitum feeding and drinking. When feed and water facilities are not shaded, cows need to choose between the comfort of shade or feeding and drinking. Decreased feeding and water consumption leads to lower milk production (Bucklin et ai., 1991). Roman-Ponce et ai. (1976) reported that animals with shaded feeding and drinking facilities experienced lower respiration rates and rectal temperatures, increases in milk production by 10.7%, and improved conception rates by 25.3% - 44.4% in comparison to unshaded facilities. 1.2.3

MECHANICAL VENTILATION Mechanical ventilation systems can be used in combination with shade,

evaporative cooling systems or both to enhance air movements and help reduce heat stress during hot weather conditions. To be most effective mechanical ventilation should be used to enhance the natural ventilation provided by the environment and never against it (Brouk et ai., 2003). Factors that need to be considered when combining natural and

19

mechanical ventilation include the proper design of the building, barn orientation, sidewall height, roof sloping, ridge opening and building width (Brouk et al., 2003). Research by Meyer et ai. (2002) reported cows cooled with axial fans averaged lower respiration rates, greater dry matter intakes, and produced more milk than cows with no fans. Spain and Spiers (1998) reported supplemental fan cooling helped decrease body temperature. However Lin et al. (1998) reported fans alone are not as effective as a combination of spray and fan systems.

Factors that need to be considered with

mechanical ventilation include type of fan to be used, motor ability, rate of air exchange, air distribution, air velocity, blade speed, housing design, clearance and blade shape. However, to maintain maximum working efficiency of fans, proper maintenance and service should be monitored and recorded. Different fans provide different levels of effectiveness and fulfill different purposes to optimize ventilation for specific cooling systems (Lee and Back, 2001). Choosing a mechanical ventilation system that is both cost effective and easy to set up is important and can be beneficial to your herd and farm. Tunnel ventilation is used to generate a specific interior air speed; circulation fans are used inside of buildings to mix and distribute air; and cooling fans are used in buildings to direct air at or past objects or surfaces (Stowell et ai., 2003). Shearer et ai. (1999) recommends the following: 1) use fans with 0.5-1.0 hp that are capable of producing air flow rates of 11,000 cfm or greater; 2) mount 36 in fans above animals and combine with sprinklers which are spread every 30 ft apart; 3) mount 46 in fans above animals and combine with sprinklers which are spread out every 40 ft; 4) angle the fan (20-30°) downward toward the animal; 5) use an air velocity of 400-600 ft per minute; and 6) run sprinkling systems for 1-2 minutes at 15

20

minute intervals depending on the temperature. Mechanical ventilation is a critical factor that can help to improve cow comfort during heat stress conditions.

1.2.4

EVAPORATIVE COOLING SYSTEMS In combination with shade systems, evaporative cooling systems such as foggers,

misters and sprinklers can be used to help alleviate heat stress in animals when ambient temperatures are above the normal ranges (24-27° C or 75-80° F) (Bucklin et al., 1991). Evaporative cooling systems help to enhance heat loss through the animal's skin surface and respiratory tract to bring the animal back to thermal comfort (Bucklin et al., 1991). The difference between a fog, mist or sprinkling system is the droplet size. Fogging systems disperse small droplets of water that evaporate before reaching the ground, cool the surrounding air around the animal and help to keep floors or free stalls clean and dry. This system uses the least amount of water, but tends to increase relative humidity and requires enhanced maintenance to clean water filters and prevent clogs. Misting systems also spray small water droplets into the air, which helps to cool the surrounding air as it evaporates. Animals breathe in cooled air and exchange heat from the animal's body. Research by Kelly and Bond (1985); Shultz (1988); Weirsma and Armstrong (1988); Bray (1992); Shearer et al. (1999) reported misting systems helped to reduce heat stress in places with low humidity. In hot, humid areas, Bucklin et at. (1988) reported that misting systems did little to cool animals. During windy conditions or in combination with mechanical ventilation, fog and misting systems do not work as effectively due to the ventilation system blowing the fog or mist away from the animals (Lin et al., 1998). Also, wetting of feeds can lead to moldy, unhealthy feeds for animals.

Sprinkling

systems spray larger water droplets that land on the animals' hair or skin and help to cool

21

the animals as the droplets evaporate. Using larger water droplets proved to be more effective in cooling animals in humid areas more effectively than fogging and misting systems (Strickland et al., 1989; Flamenbaum et al., 1986). Sprinkling systems have also shown to decrease body temperature (Turner et al., 1991; Igono et al., 1987; Bucklin et al., 1991), reduce respiration rates (Brouk et a!., 2001); increase feed intake (Igono et a!',

1987; Strickland et al., 1989; Turner et al., 1991) and boost milk production (Flamenbaum et a!., 1986; Igono et al., 1987; Strickland et al., 1989; Bucklin et a!., 1991; Turner et al., 1991; Brouk et al., 2001). Sprinkling systems work most effectively when combined with forced ventilation (Turner and Bucklin, 1990; Bucklin et al., 1991; Brouk et al., 2003). Studies done by Hillman et al. (2001) and Brouk et al. (2003), reported increased heat loss from the body surfaces of cattle when wetting frequency and airflow rates were increased.

To effectively cool animals, Brouk et a!. (2003)

recommends soaking them every 5 minutes with fan cooling during severe heat stress conditions and every 10 minutes with fan cooling during moderate heat stress conditions. Strickland et a!. (1989) and Turner et al. (1991) reported that animals cooled with integrated systems increased milk production by 3.6 kg/cow/day or 7.9lb/cow/day, which is a 15.8% increase in milk yield. Correa-Calderon et al. (2002) reported cows cooled with both spray and fan cooled systems (E) averaged more milk production 30.5 ± 0.94 kg/day, than cows cooled with just shade (S) 26.6 ± 0.98 kg/day. The fat and protein in milk between (E) group 3.30 ± 0.061 and 3.19 ± 0.047% and (S) 3.30±0.062 and 3.28±0.048%; while somatic cell count average was higher for (S) group 313919 ± 120530 cells compared to (E) group 293019 ± 118542 cells. Respiration rate was greater for (S) group 87.8 ± 1.8 breaths/minute compared to (E) group 68.7 ± 1.7 breaths/minute.

22

As a result, pregnancy rates were higher for (E) group compared to (S) group 92% vs. 50%. Koubkova et al. (2002) reported significantly higher rectal temperatures from (37.3 to 39.3 DC), lower respiration rates (64 vs. 81 breaths/minute), and pulse rate from (28 vs. 81 pulse/minute) with sprinkler cooling compared to the control.

Bucklin (1988)

reported cooled animals consumed 1.3 kg/cow/day or 2.8 lb/cow/day more feed than uncooled control animals and produced 2.1 kg/cow/day or 4.6 lb/cow/day more milk or an 11.6% increase in milk production. Both Igono et al. (1987) and Brouk et al (1999) reported similar results with animals producing about 2.0 kg/cow/day (4.4 lb/cow/day) more milk than cows in shade alone. The type or size of the nozzle depends on the amount of water volume or flow rate that is desired. Most commonly used is the 10 (psi) low pressure 180 degrees spray nozzles which deliver about 0.05 inches of rainfall per sprinkling cycle.

Sprinkler

spacing should give an overlapping coverage pattern. Filters may be used to help prevent clogs in nozzles. Integrating such cooling systems as shade, well-ventilated structures and sprinkling systems can help to minimize thermal radiation induced heat stress. They also help to maximize performance and comfort, allowing animals to produce to their fullest genetic potential (Bucklin et aI., 1991; Shearer et al., 1999).

An effective cooling

sprinkling system will provide the following: 1) mechanical ventilation, 2) enough shade per animal, 3) clean available drinking water, and 4) an environmental sound system that prevents water runoff and waste management problems. In summary, heat stress in dairy cattle has been well established and documented. Negative effects of heat stress include a decline in both feed intake and

23

productive/reproductive efficiencies. However, only a handful of studies determining the effectiveness levels of different types of cooling systems have been documented here in Hawaii.

Therefore, the following studies were conducted to compliment existing

research and to evaluate and find the most effective cooling systems for dairy cows in Hawaii.

Such cooling systems allow animals to produce to their maximum genetic

potential.

24

CHAPTER 2 EFFECTS OF HEAT STRESS ON DAIRY CATTLE USING DIFFERENT COOLING SYSTEMS

2.1 INTRODUCTION

Heat stress in subtropical and tropical areas is an important factor and a major concern that dairy producers face everyday.

Heat stress on dairy cattle has been

documented for many years and is known to have negative effects on the productive, reproductive and physiological aspects and the overall health and well-being of the animals (Ingraham et al., 1974; Roman-Ponce et al., 1976; Hahn, 1985; Bucklin et al., 1991; Shearer et al., 1991; Armstrong, 1994).

Heat stress can be minimized by

incorporating feasible shade structures and cooling systems which help to provide crucial overall cooling and comfort for animals (Ingraham et al., 1974; Roman-Ponce et al., 1976; Hahn, 1985; Bucklin et al., 1991; Shearer et al., 1991; Armstrong, 1994). Other considerations that help alleviate heat stress include improving the animal's genetics to become less sensitive to the heat stress conditions, improving feeding techniques or rations to help minimize heat production and maintaining overall good sanitary management of farms. The overall objective of these experiments was, therefore, to determine the effects of heat stress on lactating dairy cows under different cooling systems in a tropical climate atmosphere on several dairies located in Hawaii. Three experiments were conducted on three commercial dairies within 1 km apart.

In

experiment 1, the objectives were to: (1) Evaluate the effectiveness of different types of cooling systems in connection with maintaining cow comfort using RR and THI values, and (2) Evaluate systems performance using 305 days estimated milk production. In

25

experiment 2, the objectives were to: (1) Evaluate the effectiveness of different types of cooling systems in connection with maintaining cow comfort using ST, RT and THI values; (2) Evaluate systems performance using 305 days estimated milk production; (3) Evaluate the effectiveness of an additional sprinkler system in connection with maintaining cow comfort using ST and RT. In experiment 3, the objectives were to: (1) Evaluate system performance between (1 st 20 vs. 2nd 20 animal reading); (2) Evaluate systems performance between (Dry vs. Wet hair coat animal readings); (3) Evaluate system performance between (AM vs. PM animal readings); (4) Evaluate systems performance between (Hair Coat Color).

Parameters that were measured included

respiration rates, skin temperatures, rectal temperatures, 305 days estimated milk production and temperature humidity index.

The Institution Animal Care and Use

Committee (IACUC) approved this research protocol (number 01-012) on May 29th , 2001.

2.2 MATERIALS AND METHODS This research was conducted in the hot, humid summer months (September-October) of 2002 and in the cool winter months (February-March) of 2003 at three dairy herds located in Waianae on the island of Oahu. Total number oflactating animals per farm for Dairy A = 640 head; Dairy B = 940 head; and Dairy C = 1300 head. study were lactating Friesian Holstein dairy cows. experiments were designated as: [Dairy A (SI, S2, S3, S4)]; [Dairy B

=

=

All animals in this

Treatment pens for the various

Pens with Zinc Corrugated Shade Structures

Saudi Korral Kool Bam with Galvanized Shade Structure

(SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF); No Shade Structure over the Feed Manger (NS)] [Dairy C = 36-inch

26

Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. Animals were milked twice a day for Dairy A and three times per day for Dairies Band C. During the experiments, animals were accessible to feed and water ad libitum and a total mixed ration was fed twice per day for Dairy A and three times per day for Dairies Band C in designated treatment pens. Dairy A consisted of four pens (corrugated zinc roof shade structure) [S 1, S2, S3, S4] with an average of 75-100 lactating Holstein dairy cows housed in each pen.

The

characteristics for pen SI were 27.4 m long x 5.2 m wide (90 ft x 17 ft) and tilted at one side with eave heights of 3.2 m and 3.8 m

(10~

ft and

12~

ft) above the ground. Pen SI

was a soil based rubber tire bedding two-row free stall bam with 45 free stalls on each side face to face. The orientation of the shade structure was in a southwest to northeast direction. Pen S1 was equipped with 0.9m (36in) diameter Schaffer stationary circulation fans with 0.38 - kW (0.5 hp) motors (n = 22). A single row of fans were mounted every 3.7 m (12 ft) over the free stalls and angled down at a 300 angle above the dirt stalls. Airflow delivery rates per fan ranged from 283 to 325 m 3/minute (10,000 to 11,500 cfm) according to the manufacture data. However, these fans were never used during the experiment. The characteristics for the two shade structures in pen S2 front = 14.6 m long x 7.3 m wide (48 ft x 24 ft) and 3.4 m (11 ft) above the ground with an east-west orientation and S2 back = 28.8 m long x 6.4 m wide (94.5 x 21 ft) and 3.4 m (11 ft) above the ground with a northwest-southeast orientation. The characteristics for pens S3 and S4 were similar at 36.6 m long x 4.9 m wide (120 ft x 16 ft) and tilted at one side with eave heights of 3.5 m and 3.8 m (11 ~ ft and 12Y2 ft) above the ground. The orientations of the

27

shade structure for these pens were northwest-southeast direction. Pens S2, S3, and S4 were not equipped with any other cooling devices. Dairy B consisted of 3 pens (SK, UOF, NS) with an average of 125-130 lactating Holstein dairy cows per pen that were housed under a galvanized roof shade structure. The characteristics for pen SK were 82 m long x 16.8 m wide (270 ft x 55 ft) and tilted at one side with eave heights of 3.4 m and 4.9 m (11 ft and 16 ft) above the ground. The orientation of the shade structure for this study was located in an east-west direction. Pen SK was equipped with a Saudi Korral Kool Bam system that ran continuously (n

=

10).

The characteristics for pen UOF were 68.6 m long x 9.1 wide (225 ft x 30ft) and tilted at one side with eave heights of 4.3 m and 4.6 m (14 ft and 15 ft) above the ground. The orientation of the shade structure for this study was located in an southwest-northeast direction. Pen UOF was equipped with seventeen 0.9 m (36 in) diameter Universal fogger fans with 1.5 hp motors. A single row of fans were mounted every 4.6m (I5ft) blowing into a Galvanized Shade Structure 10-feet away and angled down at a 35°-40°. The characteristics for pens UOF and NS in experiment 2 and 3 were similar, no shade or cooling system above the feed manger. The orientation of the feed mangers for this study was located in a north-south direction. Dairy C consisted of two pens with 130-150 lactating Holstein dairy cows per pen that were housed under a corrugated aluminum roof shade structure. The characteristics for the two shade structures in pen SF front = 103.6 m long x 6.7 m wide (340 ft x 22 ft) and 4.9 m (16 ft) above the ground and SF back = 48.8 m long x 6.1 m wide (160 ft x 20 ft) and 6.1 m (18 ft) above the ground. The orientation of the semi-circle shade structure

for pen SF front was located in an east-northwest direction and SF back was located in an

28

east-west direction. Pen SF front was equipped with ten 0.9 m (36 in) diameter Schaffer stationary circulation fans with 0.38 kW 0.5 hp motors. This single row of fans was mounted every 4.3 m (14 ft) over the free stalls and angled down at a 300 angle above the concrete floor feeding area.

Airflow delivery rates per fan ranged from 283 to 325

m 3/minute (10,000 to 11,500 cfm) according to the manufacture specs. characteristics for the two shade structures in pen SM front

=

The

126.2 m long x 6.7 m wide

(414 ft x 22 ft) and 4.3 m x 4.8 m (14 ft x 16 ft) above the ground and SM back = 121.9 m long x 6.1 m wide (400 ft x 20 ft) and 5.5 m (18 ft) above the ground. The orientations of the shade structure for both pens SM front and SM back were in a north-south direction. Pen SM was equipped with a misting system that ran continuously during the day. Photographs of the different types of cooling systems located on experimented farms are located in appendix A.

2.2.1

Experiment 1

In experiment 1, Dairy Herd Improvement (DHI) records for the three experimental dairy farms located on the island of Oahu were used in the study. Measurements used to evaluate effectiveness of cooling systems included milk production, respiration rates, and temperature-humidity index (THI).

For each of the seasons estimated 305 day milk

production was obtained for each cow from DHI records.

Respiration rates were

measured randomly twice daily between [lOOO-llOOh and 1300-1400h] for each cow during the test period date [Summer

=

September-October 2002; Winter

=

March 2003] by counting flank movements over a 60 second period.

FebruaryAmbient

temperature and humidity were measured 4 times per testing period daily inside

29

(measurements taken under experimented cooling system) and outside (measurements taken with direct contact with outside environment) during the experiment pen trials and were converted into THI, based on the formula THI

=

db-(0.55-0.55rh) (db-58), where

(db) is dry bulb and (rh) is relative humidity (National Academy of Sciences, 1971; West, 1999).

Animal measurements were collected randomly each testing period in

experimented pens (sample size n).

2.2.2

Experiment 2

In experiment 2, Dairy Herd Improvement (DRI) records for the two dairy farms on the island of Oahu were used in the study. Measurements used to evaluate effectiveness of cooling systems included milk production, skin temperatures, rectal temperatures, and THI. For each of the seasons estimated 305 day milk production was obtained for each cow from DHI records. Skin and rectal temperatures were measured randomly twice daily between Dairy B [Pen SK = AM (0800-0900h); PM (1300-1400h); Pen UOF

=

AM

(1000-1100h); Pen NS = PM (1400-1500)h]; [Dairy C = Pen SM = AM(900-1000h); PM (1200-1300h)] during the test period [Summer = September-October 2002; Winter = February-March 2003]. Also during experiment 2, Dairy B pens, SK and UOF was later equipped with an additional nozzle sprinkler system above the feed manger and skin and rectal temperatures were monitored. Skin temperatures were measured by scanning the cow in a cross section with an omega 05540 infrared sensory radar gun to determine the overall average temperature of animals in each experimented pen and then recorded. Rectal temperatures were measured by inserting a digital thermometer in the rectum, for a 60 second period and the value recorded. This was done while animals were caught in stanchions at the feed manger. Ambient temperature and humidity were measured 4

30

times per testing period daily inside (measurements taken under experimented cooling system) and outside (measurements taken with direct contact with outside environment) temperature during the experiment pen trial and converted.into TRI, based on the formula TRI

=

db-(0.55-0.55rh) (db-58), where (db) is dry bulb and (rh) is relative humidity

(National Academy of Sciences, 1971; West, 1999).

Animal measurements were

collected randomly each testing period in experimented pens (sample size n). 2.2.3

Experiment 3

In experiment 3, measurements used to evaluate cooling systems included skin and rectal temperatures. Skin and rectal temperatures for each cow were taken randomly twice daily between Dairy B [Pen SK = AM (0800-0900h); PM (1300-1400h); Pen UOF =

AM (1000-1100h); Pen NS = PM (1400-1500h)]; [Dairy C = Pen SM = AM(900-

1000h); PM (1200-1300h)] during the test period [Summer Winter = February-March 2003].

=

September-October 2002;

Skin and rectal temperatures were measured as

previously described for experiment 2. Research was conducted on Dairy B, pen SK, UOF and NS to evaluate systems performance between (1 st 20 vs. 2nd 20 animal readings) as animals returned to the feed manger after getting milked.

Research was also

conducted on Dairy C pen SM to evaluate systems performance between (Dry vs. Wet hair coat color animal readings). Animals were considered to be wet when the hair coat was more than 25% wet and dry animals were completely dry. In addition, research was also conducted on Dairies Band C to evaluate system performance between (AM vs. PM) and (Hair Coat Color). Animal measurements were collected randomly each testing period in experimented pens (sample size n).

31

2.3 STATISTICAL ANALYSIS Statistical analyses using analysis of variance (ANOVA) in the general linear models (GLM) procedure of SAS (1999) were conducted on the data for milk production, respiration rates, skin temperatures, rectal temperatures, and THI. Significant means (P :::; .05, P :::;.01, P :::;.0001) were separated by Duncan's multiple range test (SAS, 1999). Data were considered significantly different when (P :::;.05). Data were presented using Harvard Graphics version 2.0 (Copy Right

©

1991-1993) Software Publishing

Corporation. 2.4 RESULTS AND DISCUSSION 2.4.1

Experiment 1

2.4.1.1 Respiration Rates Respiration rate results (breaths/minute) for experiment 1 during the test period are presented in Figures 1 through 12. The results of the respiration rate (RR) measurements during the sampling period are presented in Figures 1 through 6. Figure 1 presented the RR measurements between dairies across the summer and winter seasons. Respiration rates (breaths/minute) were significantly higher (P :::;.0001) for cows in dairy A (79 ± 0.32), followed by Dairy C (70 ± 0.49) and lowest was Dairy B (58 ± 0.31). These results further suggest that the cooling systems in Dairy B pens SK and UOF were the most effective in lowering RR in comparison to the other types of cooling systems across the seasons. Figure 2 presented the RR measurements within dairies between the summer and winter seasons. Respiration rates (breaths/minute) were significantly higher (P :::;.0001) during the summer vs. winter period for all dairies.

32

Dairy A reported, (88 ± 0.4)

compared to (70 ± 0.3); Dairy B reported, (63 ± 0.39) compared to (52 ± 0.39); Dairy C reported, (80 ± 0.69) compared to (60 ± 0.5) for summer vs. winter periods. These results suggest that animals during the summer seasons were affected by the higher summer temperatures which resulted in higher RR when compared to the winter seasons. These results further suggest that Dairy B's combined cooling systems were the most effective in lowering RR with minimal increases between the experimented seasons. Figure 3A presented the RR measurements between pens within the summer seasons. Overall, Dairy B pens reported the lowest RR values followed by Dairy C pens and then followed lastly by Dairy A pens. Significant differences (P =::; .0001) were observed between the two types of cooling systems within Dairy B during the summer season. These results indicated pen SK had animals with lower RR (breaths/minute) (60 ± 0.52) than those animals in pen UOF with (65 ± 0.55). These results further suggest that the Saudi Korral Kool system SK was more effective in lowering RR then the universal oscillating fogging system UOF.

Significant differences (P ::::;; .0001) were observed

between the two types of cooling systems within Dairy C during the summer season. These results indicated pen SM had animals with lower RR (breaths/minute) (71 ± 0.94) than those animals in pen SF (89 ± 0.71). These results further suggest that the misting system in pen SM was more effective in lowering RR then pen SF which was equipped with schaffer fans.

Respiration rates (breaths/minute) were significantly higher (P ::::;;

.0001) among pens Sl and S2; pens Sl and S4; pens S2 and S4 within Dairy A during the summer season. However, no significant differences (P

~.05)

between pens S1 and S3

were observed. Pen Sl animals reported the lowest RR (breaths/minute) (84 ± 0.79) followed by pen S3 (86 ± 0.84), then by pen S4 (89 ± 0.79) and lastly pen S2 (93 ± 0.65).

33

These results further suggest that RR values differed among pens with zinc corrugated shade structures which may have been due to pen locations on the experimented farms and the total amount of shaded space per cow. In addition, no significant differences (P

~

.05) were observed between Dairy A, pen S4 and Dairy C, pen SF between the summer treatment groups. These results suggest that the shade structure for pen S4 was just as effective as pen SF which was equipped with Schaffer fans during the summer period. Figure 3B presented the RR measurements between pens within the winter seasons. Significant differences (P

~

.0001) were observed between the two types of cooling

systems within Dairy B during the winter season. These results indicated pen SK had animals with lower RR (breaths/minute) (47 ± 0.46) than those animals in pen UOF (57 ± 0.54). These results further suggest that the Saudi Korral Kool system SK was more effective in lowering RR then the universal oscillating fogging system UOF. Significant differences (P

~.0001)

were observed between the two types of cooling systems within

Dairy C during the winter season. These results indicated pen SM had animals with lower RR (breaths/minute) (57 ± 0.66) than those animals in pen SF (65 ± 0.68). These results further suggest that the misting system in pen SM was more effective in lowering RR then pen SF which was equipped with schaffer fans. Significantly differences (P

~

.0001) were observed between pens Sl and S2; pens S2 and S4 within Dairy A during the winter. Pen S2 animals had the lowest RR (breaths/minute) (68 ± 0.56) followed by pen S3 (69 ± 0.66), then pen Sl (70 ± 0.54), and lastly pen S4 (72 ± 0.68). These results further suggest RR values differed among pens with zinc corrugated shade structures which may have been due to pen locations on the experimented farms and the total amount of shaded space per cow. However, no significant differences (P

34

~ .05)

were

observed between Dairy A, pens Sl and S3; and Dairy A, pen S4 and Dairy C, SF. These results suggest that the shade structure for pen S4 was effective as pen SF which was equipped with schaffer fans during the winter period. Results for Figures 1 through 3 suggest that the cooling systems at Dairy B were the most effective cooling systems followed by Dairy C and lastly Dairy A. Figure 4 presented the RR measurements across dairies, across seasons, between times. Significant differences (P ::;;.0001) were observed for RR (breaths/minute) during the PM periods at (71 ± 0.43) compared to the AM at (69 ± 0.35) between treatment groups. These results further suggest that animals were slightly cooler during the AM periods which resulted in lower RR across the seasons. Figure 5 presented the RR measurements within dairies across the summer and winter seasons between times.

Significant differences (P ::;; .01) were observed for RR

(breaths/minute) during the PM periods for Dairy A, at (80 ± 0.42) compared to AM (78 ± 0.47) and Dairy C, PM (73 ± 0.69) compared to AM (67 ± 0.69). significant differences (P

~.05)

However, no

were observed for Dairy B during the PM periods which

reported RR (breaths/minute) values of (58 ± 0.44) compared to the AM periods RR values of (57 ± 0.43). These results indicated animals during the AM periods reported lowered RR for Dairy A and Dairy C when compare to the PM periods which resulted in higher RR. These results further suggest that Dairy B' s cooling systems were the most efficient in maintaining RR at similar values in respect to the experimented times. Figure 6A presented the RR measurements between experimented pens within AM times across the summer and winter seasons. Significant differences (P ::;;.0001) were observed between the two types of cooling systems within Dairy B during the AM

35

periods. These results indicated pen SK had animals with lower RR (breaths/minute) (53 ± 0.56) than those animals in pen UOF (61 ± 0.61). These results further suggest that the Saudi Korral Kool system SK was more effective in lowering RR then the universal oscillating fogging system UOF during the experimented times. Significant differences (P ::::;.0001) were observed between the two types of cooling systems within Dairy C during the AM periods. These results indicated pen SM had animals with lower RR (breaths/minute) (61 ± 0.87) than those animals in pen SF (74 ± 0.94). These results further suggest that the misting system in pen SM was more effective in lowering RR then pen SF which was equipped with schaffer fans during the experimented times. Significant differences (P ::::;.0001) were observed between pens S1 and S2; pens S1 and S4 within Dairy A during the AM periods. differences (P

~.05)

However there were no significant

between pens Sl and S3; S2 and S4 during the AM periods. These

results indicated pen S3 had animals with the lowest RR (breaths/minute) (75 ± 0.96) followed by pen Sl (77 ± 0.77), then followed by pen S2 (79 ± 1.01) and lastly pen S4 (80 ± 0.97). These results further suggest RR values for Diary A differed between pens with zinc corrugated shade structures which may have been due to pen locations on the experimented farms and the total amount of shaded space per cow. significant differences (P

~.05)

In addition, no

were observed among Dairy A, pen S3 and Dairy C, pen

SF; Dairy B, pen UOF and Dairy C, pen SM among the AM periods. These results suggest that the shade structure for pen S3 was effective as pen SF which was equipped with schaffer fans during the summer period.

These results also suggest that the

universal fogger system was effective as the misting system in pen SM. Overall, these

36

data suggest that Dairy B were the most effective cooling systems in reducing RR during the AM periods. Figure 6B presented the RR measurements between experimented pens within PM times across the summer and winter seasons. Significant differences (P

~.0001)

were

observed between the two types of cooling systems within Dairy B during the PM periods. These results indicated animals in pen SK had lower RR (breaths/minute) (55 ± 0.62) than those animals in pen UOF (61 ± 0.57). These results further suggest that the Saudi Korral Kool system SK was more effective in lowering RR then the universal oscillating fogging system UOF during the experimented times. Significant differences (P

~.0001)

were observed between the two types of cooling systems within Dairy C

during the PM periods. These results indicated pen SM had animals with lower RR (breaths/minute) (66 ± 0.86) than those animals in pen SF (81 ± 0.93). These results further suggest that the misting system in pen SM was more effective in lowering RR then pen SF which was equipped with schaffer fans during the experimented times. Significant differences (P

~.0001)

were observed among pens S1 and S2; pens S1 and

S3; pens S1 and S4 within Dairy A during the PM periods. However, there were no significant differences (P ;:::.05) among pens S2 and S3; pens S2 and S4; pens S3 and S4 during the PM periods. These results indicated pen S1 had animals with the lowest RR (breaths/minute) (77 ± 0.75) followed by pen S3 (80 ± 0.87), then followed by pen S4 (81 ± 0.91) and lastly pen S2 (82 ± 0.84). These results further suggest RR values in Dairy A differed between pens with zinc corrugated shade structures which may have been due to pen locations on the experimented farms and the total amount of shaded space per cow. In addition, no significant differences (P ;:::.05) where observed among Dairy A, pen S2,

37

S3, S4 and Dairy C, pen SF between the PM periods. These results suggest that the shade structures for pens S2, S3, and S4 were just effective as pen SF which was equipped with Schaffer fans during the winter period. Overall, these data suggest that Dairy B was the most effective cooling systems in reducing RR. Results for figures 4 through 6 suggest that cooling systems at Dairy A, Dairy B, and Dairy C during the AM times reported lower RR when compared to the PM times during the study except for Dairy B that did not differ during AM and PM times. Many researchers have been using RR as indicators of climatic stress. The normal RR measurement range for dairy cattle is 26-50 breaths/minute (The Merck Vet. Manual 8th edition, 1998). All RR in this experiment were above the normal range ofRR except for Dairy B pen SK during the winter period (47 ± 0.46) breaths/minute. These results indicate that the experimented cooling systems during this experiment provided partial relief to the heat stress conditions. These conditions may have been due to environmental stressors such as higher temperatures and humidity levels here in Hawaii. Results found in this study were similar to experimented results found by Correa-Calderon et al. (2002) who reported (68.7) breaths/minute under combined water spray sprinkler and fan cooling systems under shade compared to animals with just shade (87.8) breaths/minute. These results from this research proj ect suggest that integrated systems were the most effective in minimizing heat stress (shade, mechanical ventilation and water sprinkling system) followed by the (shade and misting system) and finally, just shade systems. To help minimize heat stress and maximize cow comfort and production, integrated environmental modifications should be used in hot humid climate zones.

38

2.4.1.2 Milk Production

Milk production (estimated 305 days) during the study period was presented in Figures 7 through 9. Figure 7 presented the milk production measurements between dairies across the summer and winter seasons. significantly higher (P

~.0001)

significant differences (P

Average milk production was

for cows in Dairy B at (14,592 ± 404 kg). However, no

~.05)

in milk production were observed between Dairy A at

(13,383 ± 303 kg) and Dairy C at (13,557 ± 395 kg) across the seasons. These results further suggest that Dairy B pens was the most effective in cooling animals in respect with the milk production produced for the total 305 days estimated milk. Figure 8 presented the milk production measurements between the summer and winter seasons within the experimented dairies. significantly higher (P

~.01)

Average milk production was

during the winter seasons for Dairy A at (13,728 ± 380 kg)

compared to (12,856 ± 491 kg) during the summer seasons. However, no significant differences (P

~.05)

were observed in Dairy Bat (14,325 ± 562 kg) compared to (14,847

± 581 kg); and dairy Cat (13,430 ± 680 kg) compared to (13,630 ± 486 kg) between the

experimented seasons. These results indicate that Dairy B and Dairy C pens reported similar milk production values between seasons which suggest that the environmental modifiers used in specific dairies were not affected by experimented seasons. However, Dairy A pens reported a difference in milk production values between the seasons which suggests that the experimented pens in Dairy A were affected by the experimented seasons. This may have been due to no additional environmental modifiers incorporated into shade structures.

39

Figure 9A presented the milk production measurements among experimented pens within the summer seasons. There were no significant differences (P ;;:: .05) observed between the two types of cooling systems within Dairy B during the summer season. These results indicated pen SK 305 days estimated milk production (14,506 ± 834 kg) was slightly higher than those animals in pen UOF (14,157 ± 763 kg). There were no significant differences (P ;;:: .05) observed between the two types of cooling systems within Dairy C during the summer season. These results indicated pen SM 305 days estimated milk production (13,936 ± 816 kg) was slightly higher than those animals in pen SF (12,419 ± 1170 kg). There were no significant differences (P ;;::.05) observed among pens SI and S2; pens SI and S3; pens SI and S4; pens S2 and S3; pens S2 and S4; pens S3 and S4 within Dairy A during the summer season. These results indicated pen S4 reporting the highest 305 days estimated milk production (13,388 ± 1167 kg), followed by pen S3 (13,334 ± 107 kg), then followed by pen S2 (12,510 ± 981 kg) and lastly pen SI (12,433 ± 804 kg). Figure 9B presented the milk production measurements among experimented pens within the winter seasons. There were no significant differences (P ;;::.05) observed for Dairy B during the winter seasons. These results indicated pen SK 305 days estimated milk production (14,974 ± 775 kg) was slightly higher than those animals in pen UOF (14,722 ± 871 kg). There were no significant differences (P ;;::.05) observed between the two types of cooling systems within Dairy C during the winter season. These results indicated pen SM 305 days estimated milk production (14,116 ± 760 kg) was slightly higher than those animals in pen SF (13,172 ± 596 kg).

There were no significant

differences (P ;;::.05) observed among SI and S2; pens SI and S4; pens S2 and S3; pens

40

S2 and S4 within Dairy A during the winter season. These results indicated pen S4 reported the highest 305 days estimated milk production (14,361 ± 761 kg), followed by pen SI (13,975 ± 544 kg), then followed by pen S2 (13,258 ± 751 kg) and lastly pen S3 (13,179± 1141 kg). It has been well-documented, and researchers have reported that during periods of

heat stress, feed intake and consumption declines (Brown-Brandl et al., 2003; Podmanicky et al., 2002; West et al., 2002) which leads to decreases in milk production (Johnson, 1987; Turner, 1998; Podmanicky et al., 2002; West et al., 2002). Dairy B reported the highest 305 days estimated milk production levels for all dairies during the experimented periods followed by Dairy C and lastly Dairy A. This may have been due to the types of cooling systems on each specific dairy. Providing efficient cooling and management systems helps to provide cow comfort and maximize milk production. 2.4.1.3 Temperature Humidity Index

Ambient temperature and humidity were converted into a temperature humidity index (THI) based on the formula THI = db - (0.55 - 0.55rh) (db - 58) where db is dry bulb and rh is relative humidity (National Academy of Sciences, 1971; West, 1999). The THI values results during the test period are presented in Figures 10 and 12. Figure 10 presented the THI values (inside vs. outside) measurements within experimented dairies across the summer and winter seasons. THI values were significantly lower (P :::;;.01) for inside temperatures for Dairy A at (78 ± 0.26 vs. 80 ± 0.26); Dairy B at (76 ± 0.3 vs. 79 ± 0.33); and dairy C at (77 ± 0.28 vs. 79 ± 0.32). THI values for figure 10 ranged from 7678 inside temperatures and 79-80 outside temperatures within the dairies, across seasons.

41

Coolest THI value readings were reported by Dairy B followed by Dairy C and lastly Dairy A. Figure 11 presented the THI values (inside vs. outside) measurements within dairies within the summer seasons. THI values were significantly lower (P ::::;;.01) for (inside vs. outside) temperatures for cows in Dairy A at (81 ± 0.21 vs. 82 ± 0.33); Dairy B at (78 ± 0.23 vs. 81 ± 0.35); and Dairy C at (78 ± 0.27 vs. 80 ± 0.31). Figure 12 presented the THI values (inside vs. outside) measurements within dairies within the summer seasons. THI values were also significantly lower (P ::::;;.01) (inside vs. outside) for cows in Dairy A at (77 ± 0.37 vs. 79 ± 0.34); Dairy B at (73 ± 0.33 vs. 77 ± 0.42); and Dairy C at (75 ± 0.43 vs. 78 ± 0.5). THI values for figure 11-12 ranged from 78-81 inside summer temperature in comparison to 81-82 the outside summer temperature; and 73-79 inside winter temperature in comparison to 77-79 the outside winter temperature. These results for figures 10 and 12 indicate that the inside THI readings under the different cooling systems were lower than the direct outside environment THI reading values which suggest the experimented cooling systems helped to decrease THI values.

These THI values for experiment 1 were considered to be

between mild heat stress to stress conditions for animals (Wiersma, 1990; Armstrong, 1994). Research by Buffington et al. (1981); Igono et at. (1992); Armstrong, (1994); Brouk et at. (1999) reported negative affects to dairy cows production levels when the THI value exceeds 72. The results from experiment 1 demonstrate that all THI values are over 72, suggesting that animals in this experiment were stressed. Ultimately, animals in experiment 1 gained more heat from the environment then they could lose which resulted in heat stressed animals.

These results suggest that high temperatures and humidity

42

levels here in a tropical/subtropical area lead to heat stress. Results for experiment 1 also suggest that cooling systems in Hawaii may help to provide partial relief to the animals under heat stress conditions.

2.4.2

Experiment 2

2.4.2.1 Skin and Rectal Temperatures The results for experiment 2 are presented in Figures 13 through 23. The results for skin temperature (ST) and rectal temperature (RT) measurements during the test period are presented in Figures 13 through 16.

Figure 13 presented the ST measurements

between pens within the summer and winter seasons across dairies.

ST during the

summer were significantly higher (P :::;.0001) for cows in pens UOF, at (34.1 ± 0.39 °C) and NS, at (34.5 ± 0.51 °C) compared to pen SM, at (29.5 ± 1.85 °C) and SK, at (31.5 ± 0.33 °C). However, there were no significant differences (P ;;::.05) observed during the summer for pens SM and SK; and UOF and NS. These results may have been due to pens UOF and NS not having shade structures above the experimented area and pens being located right across of each other. These results also suggested that the misting system in pen SM was just as effective as pen SK during the experimented season. Significant differences (P :::;.0001) were observed during the winter treatment groups. ST readings are SM, at (28.7 ± 0.32 °C), SK, at (31.5 ± 0.27 °C), UOF, at (29.5 ± 0.51 °C), and NS, at (32.7 ± 0.54 °C) respectively. These results indicated that Dairy C animals reported the lowest ST followed by Dairy B's pen UOF, pen SK and lastly pen NS during the winter seasons. However, pen UOF reported lower ST compared to pen SK which may have been due to the type of cooling system. Pen SK may have increased the rh of the environment through the evaporative system, which may have resulted in higher

43

environment temperatures and increased ST readings for pen SK during the experimented trials. Figure 14 presented the RT measurements between experimented pens within the Significant differences (P :::; .0001) were

summer and winter seasons across dairies.

observed among Dairy B pens SK and UOF; Dairy B pens SK and NS; Dairy B pen SK and Dairy C pen SM during the summer season. The results indicated that the cooling system in Dairy B pen SK (39.4 ± 0.07 DC) was the most effective in lowering RT compared to the other cooling system of Dairy C pen SM (39.6 ± 0.04 DC) and lastly followed by Dairy B pens UOF and NS (40.1 ± 0.08 DC) and (40.1 ± 0.08 DC). There were no significant differences (P

~.05)

observed between Dairy B pens UOF and NS.

These results may have been due to pens UOF and NS not having shade structures above the experimented area and pens being located right across of each other. Figure 15 presented the ST measurements across experimented dairies across the summer and winter seasons within times (AM and PM). Significant differences (P :::;.01) were observed between Dairy C pen SM and Dairy B pens SK and UOF during the AM period. These results indicated that the cooling systems in Dairy C pen SM (28.2 ± 0.27 DC) was the most effective in lowering ST compared to the animals in Dairy B pen SK

(31.8 ± 0.41 DC) followed by pen UOF (32.0 ± 0.17 DC) during the AM period. However, there were no significant differences (P

~

.05) between Dairy B pens SK and UOF.

These results suggest that during the AM periods, the cooling systems in pens SK and UOF reported similar cooling results for experimented types of cooling systems for ST during the AM period. Significant differences (P < .01) were observed between Dairy C pen SM and Dairy B pen UOF; Dairy B pen SK and Dairy B pen UOF during the PM

44

period. However, there were no significant differences (P

~.05)

observed between Dairy

C pen SM and Dairy B pen SK. The results indicated that the cooling systems in Dairy B pen SK (30.3 ± 0.56 °C) and Dairy C pen SM (30.2 ± 2.32 °C) reported similar cooling results for experimented types of cooling systems and were the most effective in lowering ST compared to the other cooling system of Dairy B pen UOF (33.6 ± 0.39 °C) during the PM period. Figure 16 presented the RT measurements between experimented dairies across the summer and winter seasons within times (AM and PM) across dairies.

Significant

differences (P =::;.0001) were observed between all dairies and experimented pens during the AM period. These results indicate that the cooling systems in Dairy B pen SK (39.2 ± 0.06 °C) was the most effective in lowering RT compared to the other cooling systems of Dairy C pen SM (39.4 ± 0.04 °C) and lastly, followed by Dairy B pen UOF (39.8 ± 0.07 °C) during the AM period.

Significant differences (P =::; .0001) were observed

among all dairies and experimented pens during the PM period. These results indicated that the cooling systems in Dairy B pen SK (39.2 ± 0.1 °C) was the most effective in lowering RT compared to the other cooling systems of Dairy C pen SM (39.6 ± 0.06 °C) and lastly followed by Dairy B pen UOF (40.0 ± 0.07 °C) during the PM period. Skin temperatures are usually 10-20 °C (18-36 OF) below the core body temperature depending on the cows hide and environmental factors.

The normal core body

temperature ranges from 37.8-39.4 °C (100-103 OF): cows average (38.6 °C) (101.5 OF) (Ensminge and Perry, 1997). The normal RT ranges from 38.0-39.3 °C (100.4-102.8 OF) cows average 38.6 °C (101.5 OF) (Ensminger and Perry, 1997; The Merck Vet. Manual 8th Edition, 1998). Research studies completed by (Ingraham et al. 1974; Roman-Ponce et

45

ai. 1976; Fuquay, 1981; Hahn, 1985; Johnson, 1987; Bucklin et ai. 1991; Shearer et ai. 1991; Annstrong, 1994; Turner, 1998) report increased body and rectal temperatures during periods of heat stress. These results from this research project suggest that the integrated cooling systems (Dairy B pen SK and Dairy C, pen SM) were the most effective in cooling the animals ST and RT during the experimented trials. However, due to the high temperature and humidity levels here in Hawaii, all ST and RT values were above the normal ranges with exception of Dairy B pen SK which reported values within the normal skin and rectal temperatures ranges. This data suggest animals suffered heat stress. Therefore, providing supplemental cooling systems during periods of heat stress in the tropicaVsubtropical areas is crucial for animal comfort and production. 2.4.2.2 Milk Production

Milk production (305 days milking) during the study period were presented in Figures 17 through 19. Figure 17 presented the milk production measurements between dairies across the summer and winter seasons. There were no significant differences (P

~.05)

observed for estimated 305 days milk production for cows in Dairy B at (13,910 ± 249 kg) and Dairy C at (13,834 ± 339 kg). These results indicate that Dairy B pens SK and UOF and Dairy C pen SM reported similar values across seasons for estimated milk production. Figure 18 presented the milk production measurements between the summer and winter seasons within the experimented dairies. There were no significant differences (P ~.05)

observed during the summer and winter seasons for Dairy B at (13,784 ± 299 kg)

compared to (14,090 ± 429 kg); and dairy Cat (13,588 ± 456 kg) compared to (14,111 ± 502 kg). These results indicated that Dairy B pen SK and Dairy C pen SM reported

46

similar milk production values between experimented seasons suggesting that experimented pens were not affected by the experimented seasons due to environmental modifications. Figure 19 presented the milk production measurements between experimented pens within the summer and winter seasons. There were no significant differences (P

~.05)

observed during the summer seasons for Dairy B pens and Dairy C pens. However, results indicate pen SK reported similar values of 305 days estimated milk production (13,705 ± 432 kg) when compared to animals in pen UOF (13,620 ± 582 kg) and pen NS (13,588 ± 456 kg) and lastly Dairy C pen SM (13,981 ± 551 kg). significant differences (P

~.05)

There were no

observed during the winter seasons for Dairy B pens and

Dairy C pens. However, results indicate pen SK reported similar values of 305 days estimated milk production (14,568 ± 955 kg) when compared to animals in pen UOF (13,705 ± 698 kg) and pen NS (14,111 ± 502 kg) and lastly Dairy C pen SM (14,062 ± 620 kg). These overall results indicate no significant differences were reported for all measured parameters during the experiment which suggest that Dairy B and Dairy C produced similar amounts of milk production.

2.4.2.3 Temperature Humidity Index Ambient temperature and humidity were converted into a temperature humidity index (THI) based on the formula THI = db - (0.55 - 0.55rh) (db - 58) where db is dry bulb and rh is relative humidity (National Academy of Sciences, 1971; West, 1999). The results of the THI values during the test period are presented in Figures 20 and 21. Figure 20 presented the THI values (inside vs. outside) measurements within experimented dairies across the summer and winter seasons.

47

THI values were

significantly lower (P ::;;.0001) for inside temperatures for Dairy B at (77 ± 0.26 vs. 85 ±0.39) and Dairy C at (78 ± 0.43 vs. 82 ±0.58). Figure 21 presented the THI values (inside vs. outside) measurements within experimented dairies within the summer and winter seasons. THI values were significantly lower (P ::;;.0001) for inside temperatures for Dairy B at (78 ± 0.27 vs. 86 ± 0.57) and Dairy C at (79 ± 0.44 vs. 83 ±0.69) during the summer seasons.

THI values were significantly lower (P ::;; .0001) for inside

temperatures for Dairy B at (76 ± 0.33 vs. 84 ± 0.51) and dairy C at (76 ± 0.62 vs. 79 ± 0.75) during the winter seasons. Results for figures 20 and 21 indicate that inside THI readings under the different cooling systems were lower than the outside THI values which suggest cooling systems helped to decrease THI values. These THI values for experiment 2 were considered to be between mild heat stress to stress conditions for animals (Wiersma, 1990; Armstrong, 1994). Research by Buffington et al. (1981); Igono

et ai. (1992); Armstrong, (1994); Brouk et ai (1999) reported negative affects to dairy cows' production levels when the THI value exceeds 72. These results from experiment 2 demonstrate that all THI values are over 72, suggesting that animals in this experiment were stressed.

Ultimately, animals in experiment 2 gained more heat from the

environment then they could lose which resulted in heat stressed animals. These results suggest that high temperatures and humidity levels here in a tropical/subtropical area lead to heat stress. Results for experiment 2 also suggest that cooling systems in Hawaii may help to provide partial relief to the animals under heat stress conditions. 2.4.2.4 Sprinkler Systems Figure 22 presented the ST (sprinkler on vs. sprinkler off) measurements during the summer for pens SK and UOF in Dairy B. ST during the summer with sprinklers off

48

were significantly higher (P ::;;.0001) when compared to sprinklers on for cows in pens SK, at (31.5 ± 0.33 °C vs. 25.3 ± 1.43 °C) and UOF, at (34.1 ± 0.39 °C vs. 30.9 ± 0.96 °C). These results further suggest additional sprinkling systems helped to decrease ST. Figure 23 presented the RT (sprinkler on vs. sprinkler off) measurements during the summer for pens SK and NS in Dairy B. RT during the summer with sprinklers off were significantly higher (P ::;;.05) when compared to sprinklers on for cows in pens SK, at (39.4 ± 0.07 °C vs. 39.2 ± 0.11 °C) and UOF, at (40.1 ± 0.08 °C vs. 38.6 ± 2.49 °C). These results indicated that additional sprinkling systems helped to decrease RT. These results further suggest that Figure 22 and Figure 23 demonstrated that using an additional sprinkler system above the feed manger helped to reduce the animals ST and RT respectively. This data also suggest that providing additional sprinkling system to the current cooling systems can help to reduce the animals' skin and rectal temperatures in addition to improving cow comfort and helping to reduce the effects of heat stress.

In

addition, all skin and rectal temperatures values during this experiment were within the normal temperature ranges for dairy cattle. Researchers have reported sprinkling systems combined with forced ventilation to be the most effective in cooling animals during periods of heat stress, (Turner and Bucklin, 1990; Bucklin et aI" 1991; Brouk et al., 2003) decreasing body temperatures, (Turner et al., 1991; Igono et al., 1987; Bucklin et aI., 1991), reducing respiration rates (Brouk, et al., 2001; increasing feed intake (Igono et al., 1987; Strickland et al., 1989; Turner et aI., 1991) and boosting milk production or

yield Flamenbaum, 1986; Igono et al., 1987; Strickland et al., 1989; Bucklin et aI., 1991; Turner et al., 1991; Brouk et al., 2001).

49

2.4.3

Experiment 3

2.4.3.1 Skin and Rectal Temperatures The results for experiment 3 during the test period for ST and RT measurements are presented in Figures 24 through 36.

Figures 24 presented the skin and rectal after

milking (1 st 20 vs. 2nd 20 animal readings) measurements across seasons for pen SK in dairy B. There were no significant differences (P ;;:::.05) observed between skin and rectal temperatures across seasons between the (1 st 20 vs. 2nd 20 animal readings) groups. ST readings were (29.1 ± 1.15 °C vs. 29.8 ± 0.7 °C) and RT readings were (38.9 ± 0.1 °C vs. 39.1 ± 0.13 °C). These results suggest that the conditions between the (1 st 20 vs. 2nd 20 animal readings) had no effect on the animal's skin and rectal temperatures for pen SK during the experimented trial. In addition, all skin and rectal temperatures values during this experiment were just slightly above the normal temperature ranges for dairy cattle. Figures 25 presented the skin and rectal temperatures after milking (1 st 20 vs. 2nd 20 animal readings) measurements across seasons for pens UOF in dairy B. Significant differences (P ::;;.05) were observed in ST readings across the seasons (32.1 ± 0.67 °C vs. 30.98 ± 0.75 °C). There were also significant differences (P ::;;.0001) observed in RT readings across the seasons (39.7 ± 0.1 °C vs. 39.3 ± 0.11 °C). These results indicated that the (1 st 20 vs. 2nd 20 animal readings) was slightly higher for the 2nd 20 animal readings. These results further suggest that the increases in skin and rectal temperatures may have been due pen UOF having no shade structure over the feed manger and the distance the animals in pen UOF had to walk from the milking parlor to an available space at the feed manger. In addition, all skin and rectal temperatures values during this experiment were just slightly above the normal temperature ranges for dairy cattle.

50

Figures 26 presented the skin and rectal temperatures after milking (1 st 20 vs. 2nd 20 animal readings) measurements across seasons for pens NS in dairy B. There were no significant differences (P

~

.05) observed between skin and rectal temperatures.

ST

readings were (33.3 ± 1.98 °C vs. 31.7 ± 2.36 DC) and RT readings were (39.9 ± 0.14 °C vs. 40.1 ± 0.11 0C). These results suggest that the conditions between the (1 st 20 vs. 2nd 20 animal readings) had no effect on the animal's skin and rectal temperatures for pen NS during the experimented trial.

Overall, results for Figures 24-26 suggest that the

measurement between the (1st 20 vs. 2nd 20 animal readings) did not differ for pen SK and pen NS2 but were significantly different for pen UOF. These results may have been different if we possibly waited for a longer period of time to measure the 2nd 20 animals or by lengthening the distance from the milking parlor for cows in pens SK and UOF. In addition, all skin and rectal temperatures values during this experiment were just slightly above the normal temperature ranges for dairy cattle. Figures 27 presented the skin and rectal temperatures between conditions (dry vs. wet hair coat animal readings) measurements during the winter for pen SM in dairy C. Skin and rectal temperatures during the winter with dry conditions were significantly higher (P ::::;.01) for cows in pen SM, at (30.0 ± 0.57 °C vs. 28.7 ± 0.36 DC) for ST and (P ::::;.0001) were significantly higher for RT at (39.9 ± 0.17 °C vs. 39.6 ± 0.06 DC). These results suggest that the wet hair coat animals were significantly cooler than the dry hair coat animals.

Studies done by Hillman et al. (2001) and Brouk et al. (2003), reported

increased heat loss from the body surfaces of cattle when wetting frequency and airflow rates were increased.

51

Figure 28 presented skin and rectal temperature within dairies across the summer and winter seasons between times. Significant differences were observed (P :::;;.0001) during the AM periods at (32.0 ± 0.17 °C) compared to the PM periods at (30.0 ± 0.56 °C). However, no significant differences were observed for RT which reported values of (39.2 ± 0.05 °C) compared to the AM periods at (39.2 ± 0.1 °C). These results indicated animals during the PM periods reported lowered ST when compared to the AM period which resulted in higher ST. This may have been due to the type of cooling system in pen SK which may have increased the rh thus increasing ST during the morning period. These results also suggest that the cooling system in pen SK was efficient in maintaining RT at similar values in respect to the experimented times. Figure 29 presented skin and rectal temperature within dairies across the summer and winter seasons between times. There were no significant differences (P ;;:::.05) observed for ST which reported values of (28.2 ± 0.27 °C) compared to the AM periods at (30.2 ± 2.32 °C).

These results suggest that the cooling system in pen SM was efficient in

maintaining ST at similar values in respect to the experimented times.

However,

significant differences (P :::;;.0001) were observed for RT during the PM periods at (39.6 ± 0.04 °C) compared to the AM periods at (39.4 ± 0.04 °C). These results suggest that

animals were slightly cooler during the AM periods which resulted in lower RT across the seasons. Figure 30 presented skin and rectal temperature within dairies across the summer and winter seasons between times. ST were observed during the AM periods at (31.7 ± 0.41 °C) compared to the PM periods at (39.7 ± 0.07 °C). RT were observed during the AM periods at (33.6 ± 0.41 0c) compared to the PM periods at (40.0 ± 0.06 °C).

52

Figure 31 presented the ST measurements for black hair coat color animals among pens within the summer and winter seasons across dairies. Significant differences (P =::;; .01) were observed for ST during the summer for cows in pens NS, at (35.0 ± 0.67 °C), UOF, at (33.9 ± 0.57 °C), SK, at (30.4 ± 1.66 °C) and SM, at (28.3 ± 0.33 °C). These results indicated that Dairy C animals reported the lowest ST followed by Dairy B's pen SK, pen UOF and lastly pen NS during the summer seasons. Significant differences (P =::;; .01) were observed for ST during the winter for cows in pens NS, at (32.6 ± 0.41 °C), UOF, at (30.0 ± 0.64 °C), SK, at (31.7 ± 0.33 °C), and SM, at (28.6 ± 0.41 °C). However, pen UOF reported lower ST compared to pen SK which may have been due to the type of cooling system.

Pen SK may have increased the rh of the environment

through the evaporative system, which may have resulted in higher environment temperatures and increased ST readings for pen SK during the experimented trials. These results indicated that Dairy C animals reported the lowest ST followed by Dairy B's pen UOF, then pen SK and lastly pen NS during the winter seasons. Figure 32 presented the RT measurements for black hair coat color animals among experimented pens within the summer and winter seasons across dairies.

Significant

differences (P =::;;.01) were observed for RT during the summer. RT readings were NS, at (40.1 ± 0.1

0q,

UOF, at (39.5 ± 0.95 °C), SK, at (39.3 ± 0.06 °C) and SM, at (39.6 ±

0.06 °C). These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy B pen UOF, then Dairy C pen SM and lastly Dairy B pen NS during the summer seasons. Significant differences (P =::;;.01) were observed for RT during the winter. RT readings were NS, at (39.9 ± 0.14 °C), UOF, at (39.5 ± 0.09 °C), SK, at (39.1 ± 0.08 °C), and SM, at (39.5 ± 0.08

0q.

However, no significant differences (P

53

~.05)

were observed for Dairy B pen UOF and Dairy C pen SM during the winter period. These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy B pen UOF and Dairy C pen SM, and lastly Dairy B pen NS during the winter seasons. Figure 33 presented the ST measurements for black/white hair coat color animals among pens within the summer and winter seasons across dairies. significant differences (P

~.05)

There were no

observed for ST during the summer for cows in pens NS,

at (33.9 ± 0.95 °C), UOF, at (33.0 ± 0.77 °C), SK, at (29.5 ± 1.04 °C) and SM, at (33.0 ± 7.57 °C). These results indicated that Dairy B pen SK animals reported the lowest ST followed by Dairy B pen UOF and Dairy C pen SM, and lastly Dairy B pen NS during the summer seasons. Significant differences (P :::;;.01) were observed for ST during the winter. ST readings were NS, at (32.8 ± 1.53 °C), UOF, at (29.1 ± 1.13 °C), SK, at (31.0 ± 0.67 °C) and SM, at (28.6 ± 0.57 °C). However, no significant differences (P ~.05)

were observed for Dairy B pen UOF and Dairy C pen SM during the winter period. These results indicated that Dairy C pen SM animals reported the lowest ST followed by Dairy B pen UOF, then pen SK, and lastly pen NS during the winter seasons. Figure 34 presented the RT measurements for black/white hair coat color animals among pens within the summer and winter seasons across dairies. Significant differences (P :::;;.01) were observed for RT during the summer. RT readings were NS, at (40.2 ± 0.19 °C), UOF, at (40.1 ± 0.2 °C), SK, at (39.4 ± 0.23 °C) and SM, at (39.6 ± 0.08 °C). However, no significant differences (P

~ .05)

were observed for Dairy B pen SK and

Dairy C pen SM; Dairy B pens UOF and NS during the winter period. These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy C pen

54

SM, then Dairy B's pen UOF, and lastly pen NS during the summer seasons. Significant differences (P ::;;.01) were observed for RT during the winter. RT readings were NS, at (39.7 ± 0.16 DC), UOF, at (39.3 ± 0.14 DC), SK, at (38.9 ± 0.17 DC) and SM, at (39.4 ± 0.14 DC). However, no significant differences (P ~.05) were observed for Dairy B pen

UOF and Dairy C pen SM during the winter period. These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy B pen UOF, then Dairy C pen SM and lastly Dairy B pen NS during the winter seasons. Figure 35 presented the ST measurements for white hair coat color animals among pens within the summer and winter seasons across dairies. Significant differences (P ::;; .01) were observed for ST for all experimented dairies during the summer. ST readings were NS, at (33.3 ± 1.2 DC), UOF, at (31.7 ± 0.68 DC), SK, at (30.2 ± 1.07 DC) and SM, at (28.5 ± 0.69 DC). These results indicated that Dairy C animals reported the lowest ST followed by Dairy B's pen SK, pen UOF and lastly pen NS during the summer seasons. Significant differences (P ::;;.01) were observed for ST during the winter. ST readings were NS, at (31.2 ± 1.39 DC), UOF, at (27.9 ± 1.06 DC), SK, at (31.6 ± 0.55 DC) and SM, at (29.0 ± 0.75 DC). However, no significant differences (P

~.05)

were observed for

Dairy B pen UOF and Dairy C pen SM; Dairy B pen SK and NS during the winter period. These results indicated that Dairy B pen UOF animals reported the lowest ST followed by Dairy C pen SM, then Dairy B's pen NS, and lastly pen SK during the winter seasons. Figure 36 presented the RT measurements for white hair coat color animals among pens within the summer and winter seasons across dairies. Significant differences (P ::;; .01) were observed for ST for all experimented dairies during the summer. RT readings

55

were NS, at (40.1 ± 0.18 °C), UOF, at (40.1 ± 0.16 °C), SK, at (39.4 ± 0.15 °C) and SM, at (39.6 ± 0.11 °C). However, no significant differences (P

~.05)

were observed for

Dairy C pen SM and Dairy B pen SK; Dairy B pen UOF and Dairy B pen NS. These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy C pen SM, then Dairy B's pen UOF and pen NS during the summer seasons. Significant differences (P =:;.01) were observed for RT during the winter. RT readings were NS, at (39.7 ± 0.2 °C), UOF, at (39.3 ± 0.16 °C), SK, at (39.1 ± 0.12 °C) and SM, at (39.6 ± 0.14 °C). However, no significant differences (P

~.05)

were observed for Dairy B pen

UOF and Dairy C pen SM; Dairy B pen UOF and Dairy pen NS and Dairy C pen SM; Dairy B pen SK and UOF during the winter period. These results indicated that Dairy B pen SK animals reported the lowest RT followed by Dairy B pen UOF, then Dairy C pen SM, and lastly Dairy B pen NS during the winter seasons. Overall, results for Figures 31-36 suggest differences among hair coat color. However, these results also express similar results between skin and rectal temperatures when compared to the types of cooling systems results in experiment 2.

56

Figure 1. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between dairies across seasons (Summer = SeptemberOctober; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P ~.OOOl).

Figure 2. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between seasons (Summer = September-October; Winter = February-March) within dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P ~.OOOl).

57

FIGURE 1: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN DAIRIES ACROSS SEASONS (SUMMER. SEPT-OCT; WINTER. FEB·MARCH IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100 95 w

~ :)

~

0

30

i

Ill:

w

A-

I/)

::c

8 . w Ill: III

z

i

ii: I/) w Ill:

_Dairies

90

85 80 75 70 65 60 55 50 45 40 35

z

,.

79:t 0.32 a 70:t 0.49

c 58:t 0.31 b

25 20 15 10 5 0

n-2226

..-1600

...1407

DAIRY A

DAlRYB

DAlRYC

n=Sample Size

(a.b,c) Means across seasons with different superscripts differ (P ~ .0001)

FIGURE 2: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN SEASONS (SUMMER = SEPT·OCT; WINTER = FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100

• ~SUMMER

95 90 85

80 75 70 65 60 55

WINTER

88:1:0.4

a

80:1: 0.69 a 70 :1:0.3 b

63:1: 0.39

60:t 0.5

a 52:t 0.39 b

b

50

45 40

35 30

25 20

15 10

5

o

DAIRY A

DAlRYB

n=Sample Size

(a,b) Means between seasons with different superscripts differ (P ~ .0001)

58

DAlRYC

Figure 3A. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Summer = September-October) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF)]; [Dairy C = 36inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P :s;.OOOl).

Figure 3B. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF)]; [Dairy C = 36inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P :s;.OOOl).

59

FIGURE 3A: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING SUMMER (SEPT-CCT) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

w

I::J

z i a:: w Q.

III

:J:

~a::

lD

w

~

z

0

~ ii:

III

w

a::

100 95

~SUMMER

93: 0.65

84:1: 0.79 ._:_:.:_:_

90

c

85

-:-:-:-:-:

89:1: 0.79 86 ~ 0.84

89:1: 0.71

b

b

80

75 70 65 60 55 50 45 40 35

[email protected][email protected]~~

-:-:-:. :..~

30

25 20

15 10 5 0

-~;~~ S1

S2 S3 DAIRY A

S4

SF SM DAlRYC

SK UOF DAlRYB

n=Sample Size

(a,b,c,d,e,t) Means within seasons with different superscripts differ (P .5 .0001)

FIGURE 3B: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING WINTER (FEB-MARCH) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100 95

.WINTER

90

85 80 75

70

70 :I: 0.54 69 :I: 0.66 72 :I: 0.68 ab 68 :l: 0.56 be a c

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60

55

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f

57 :I: 0.66

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45 40

35 30 25 20

15 10

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o

51

52 S3 DAIRY A

S4

SK UOF DAlRYB

n=Sample Size

(a,b,c,d,e,t) Means within seasons with different superscripts differ (P.5 .0001)

60

SF SM DAlRYC

Figure 4. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between times (AM = 1000-1l00h; PM = 1300-l400h) across seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P ::::;;.0001).

Figure 5. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between times (AM = 1000-1l00h; PM = 1300-l4:00h) across seasons (Summer = September-October; Winter = February-March) within dairies Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P ::::;;.01).

61

FIGURE 4: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN TIMES (AM = 1000-1100h; PM = 1300-1400h) ACROSS SEASONS (SUMMER = SEPT-OCT; WINTER = FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100 95 W

I::J

Z

:iii cr::

W DIn

~

W

cr::

aI

~

z

o

~

ii:

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cr::

• DAM _PM

90 85 80 75 70

71

69± 0.35

± 0.34 b

a

65

60 55 50 45 40 35 30 25 20 15

10 5

o

AM

PM

n=Sample Size (a,b) Means between times across seasons with different superscripts differ (P ~ .0001)

FIGURE 5: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN TIMES (AM = 1000-1100h; PM = 1300-1400h) ACROSS SEASONS (SUMMER = SEPT-OCT; WINTER = FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100 W

I::J

Z

:iii cr::

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D-

In J:

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~

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50 45 40 35 30 25 20 15

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ii:

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± 0.42 b

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± 0.69 b

57

65

60

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55

10 5

o

n=794 DAIRY A

DAlRYB

n-693 DAlRYC

n=Sample Size (a,b) Means between times across seasons with different superscripts differ (P ~ .01)

62

Figure 6A. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between pens within times (AM = 1000-11 OOh) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure lO-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P ~.OOOl).

Figure 6B. Respiration rates (breath per minute) of lactating Holstein dairy cows exposed to cooling systems between pens within times (PM = 1300-l400h) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Respiration rates of cows between treatment groups differed (P :=:;;.0001).

63

FIGURE 6A: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING AM TIMES (AM = 1000-1100h) ACROSS SEASONS (SUMMER = SEPT-OCT; WINTER = FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100 95

DAM

90 85 80 75 70

77 ± 0.77

79 ± 1.01 80 ± 0.97 a 75 ± 0.96 a

~=

=

bc

74 ± 0.94

=

=

c

61 ± 0.61 d 53±0.56=

65 60 55 50

61 ± 0.87 d

e

45

40 35 30 25 20 15 10

5

o

n=317 S1

n=309

n=235

S2 S3 DAIRY A

n=225

n=393

S4

n=401

SK UOF DAIRYB

n=351

n-342

~ DAIRYC

n=Sample Size (a,b,c,d,e) Means within time across seasons with different superscripts differ (P .:;, .0001)

FIGURE 6B: RESPIRATION RATES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING PM TIMES (PM = 1300-1400h) ACROSS SEASONS (SUMMER:: SEPT-OCT; WINTER:: FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

...::Jw

Z

:i1 a::

w

l1.

en

~

a::

lD

100 95 90 85 80 75 70 65 60

82:t 0.84 81 :t 0.91 77:t0.75 a 8°io.87 a

81 :t 0.93

a

b

55 50 45 40 35 30 25 20

15 10

5

o

S2 S3 DAIRY A

S4

SK UOF DAIRYB

~ DAIRYC

n=Sample Size (a,b,c,d,e) Means within time across seasons with different superscripts differ (P.:;, .0001)

64

Figure 7. The 305 days estimated milk production (kg) oflactating Holstein dairy cows exposed to cooling systems between dairies across seasons (Summer = SeptemberOctober; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups differed (P ::::;;.0001).

Figure 8. The 305 days estimated milk production (kg) oflactating Holstein dairy cows exposed to cooling systems between seasons (Summer = September-October; Winter = February-March) within dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups differed (P ::::;;.01).

65

FIGURE 7: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN DAIRIES ACROSS SEASONS (SUMMER - SEPT-OCT; WINTER - FEB-MARCH) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

18 17 Ii)

c z4(

tn ::l 0

%

!=. 'iii :!.

z

0

~ 0 ::l C

0

a:

Alii:

...

i

16 15 14 13 12 11 10 9 8

" .Dalries

14,592:t404

a

13,383:t 303 b

13,557 :t 395

b

7

6 5 4 3 2 1 0

rJII331

..-205

DAIRY A

DAlRYB

n-215 DAlRYC

n=S8mple Size (a,b) Means between dairies across seasons with different superscripts differ (P ~ .0001)

FIGURE 8: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN SEASONS (SUMMER SEPT-oCT; WINTER FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

=

=

18 17 Ii)

c z4( tn

::l

0

%

!=., 'iii :!.

z

0

~

0

::l C

0

a:

Alii:

... i

16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

G:3SUMMER 12,856

:t 491

WINTER

13,728 :t380

a

14,847

14,325 :t 581 :t 562 a

a

-.--

13,430 :t680

13,630 :t486

a

a

.....-----.... :~

-13

b

DAIRY A

DAlRYB

DAIRYC

n=Sample Size (a,b) Means within dairies between seasons with different superscripts differ (P ~ .01)

66

Figure 9A. The 305 days estimated milk production (kg) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Summer = SeptemberOctober) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups differed (P ~. 0 1).

Figure 9B. The 305 days estimated milk production (kg) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Winter = FebruaryMarch) across dairies in the subtropics. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups differed (P ~.Ol).

67

FIGURE 9A: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING SUMMER (SEPT-OCT) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 18

17 16 15

t:3SUMMER 12,433 :t804

14

c

13

12,510 t 981

be

12

14,157 t763 ab

13,334 t 107 abc

13,936 t816

c

-

:~rt

11 10

9 8 7 6

ii

5 4 3 2 1

o

$1

S2 S3 DAIRY A

$4

SK UOF DAIRYB

~ DAlRYC

n=Sample Size

(a.b.c,) Means within seasons with different superscripts differ (P ~ .01)

FIGURE 9B: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS DURING WINTER (FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 18

17 16 15

WINTER 13,975

13,179 t 1141

t544 ab

14,361 t 761 ab

14,974 775

t

a

14,722 871

t

a

-----,--

b

14

14,116 13,172 t596 ab

t 760 b

13 12

11 10

9

8 7 6 5 4 3 2 1

o

S1 DAiMYA

S2

53

S4

~SK~---3UuO~F

~

DAIRY B DAIRY C

n=Sample Size

(a.b) Means within seasons with different superscripts differ (P ~ .01)

68

Figure 10. Temperature humidity index (THI), inside temperature vs. outside temperature of dairy housing within dairies across seasons (Summer = SeptemberOctober; Winter = February-March) in the subtropics. THI = temperature - [(0.55 (0.55 * humidity) * (temperature - 58)]. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korra1 Koo1 Barn with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). THI between treatment groups differed (P ::;.01).

Figure 11. Temperature humidity index (THI), inside temperature vs. outside temperature of dairy housing within seasons (Summer = September-October) within dairies in the subtropics. THI = temperature - [(0.55 - (0.55 * humidity) * (temperature - 58)]. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (S 1, S2, S3 & S4)], [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)] & [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). THI between treatment groups differed (P ::;.01).

69

FIGURE 10: THI (IN Y5. OUT) OF DAIRY HOUSING WITHIN DAIRIES ACROSS SEASONS (SUMMER = SEPT-OCT; WINTER = FEB-MARCH) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

100

95 90

l::lINSlDE

OUTSIDE 80t 0.28

85

77t 0.28

~

80

75 70

79t 0.32 b

a

TIi

65 60

~

55 50

45

:::::::::::

40 35 30

25 20

~~~~~i

15 10

5

o

DAIRY A

DAIRY B

n=5ample Size (a.b) Means between conditions THI (In

~~~~ ~1~ DAIRYC

vs. Out) with different superscripts differ (P ~ .01)

FIGURE 11: THI (IN Y5. OUT) DAIRY HOUSING WITHIN SUMMER SEASONS (SUMMER = SEPT.QCT) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 100

95 90

85

I::3INSIDE

OUTSIDE

81 t 0.21 82 t 0.33

a

b

80

81 t 0.35 78 t 0.23 b

78

to.27

80 t 0.31 b

a

a

75 70

........

........ .....,._... ~

65 60 55 50

45 40 35 30

25 20

:~~::::::

~}t

15 10

5

o

DAIRY A

DAJRYB

DAJRYC

SUMMER n=Sample Size (a,b) Means between conditions THI (In vs. Out) with different superscripts differ (P ~ .01)

70

Figure 12. Temperature humidity index (THI), inside temperature vs. outside temperature of dairy housing within seasons (Winter = February-March) within dairies in the subtropics. THI = temperature - [(0.55 - (0.55 * humidity) * (temperature - 58)]. Treatment groups over the test period included: [Dairy A = Pens with Zinc Corrugated Shade Structures (Sl, S2, S3, S4)]; [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure (SK); Universal Oscillating Fogger System blowing into a Galvanized Shade Structure 10-feet away (UOF)]; [Dairy C = 36-inch Schaffer Fans under Aluminum Shade Structure (SF); Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). THI between treatment groups differed (P ::::;.01).

71

FIGURE 12: THI (IN YS. OUT) DAIRY HOUSING WITHIN WINTER SEASONS (WINTER. FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 100

95

t:JINSIDE

OUTSIDE

90

85 80

77 :to.37

79:t0.34 b

a

75 70 65

73:t 0.33

77:t 0.42 b

75:t 0.43

78 :t 0.5 b

a

60

55 50

45 40 35 30

25 20 15 10

5

o

DAIRY A

DAlRYB

DAlRYC

WINTER

n=Sample Size (a,b) Means between conditJons THI (In vs. Out) with different superscripts differ (P ~ .01)

72

Figure 13. Skin temperature (OC) oflactating Holstein dairy cows exposed to cooling systems between pens within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P :::;;.0001).

Figure 14. Rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P :::;;.0001).

73

FIGURE 13: SKIN TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS WITHIN SEASONS (SUMMER SEPT·OCT; WINTER'" FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 50 48 . [;3SUMMER INTER

=

46 44

42 40 38 36 34 32 30 28 26

34.1 31.5 ± 0.33 29.5 ± 1.85 b

± 0.39

a

34.5:1: 0.51

a

b

31.5± 0.27 28.7:1: 0.32 b 29.5:1: 0.51

a

32.7 ± 0.54 d

e

24 22 20 18 16 14 12 10

8 6 4

2

o

:-:-:-:..:

! SM

SK

DAlRYC

UOF

NS

SM

-,S!£K~_U!:!:O!l!.F!:.--!.lN~S

DAIRY C

DAlRYB

DAIRY B

n=Sample Size (a.b.c.d) Means within seasons with different superscripts differ (P ~ .0001)

FIGURE 14: RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS WITHIN SEASONS (SUMMER = SEPT-OCT; WINTER = FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 50

48 46 44

42 40

OSUMMER IIIIWINTER 39.6 39.4 40.1 ± 0.04 ± 0.07 :I: 0.08

40.1

b

e

a

±O.OB a

SM

SK

UOF

NS

39.5 ± 0.06

39.1 ± 0.66

b

e

SM

SK

39.4 39.9 ± 0.07 :I: 0.11

b

38 36 34 32 30 28 26

24 22 20 18 16 14 12 10

8 6 4 2

o

DAlRYC

DAlRYC

DAlRYB

n=Sample Size (a,b,c) Means within seasons with different superscripts differ (P =s .0001)

74

DAIRYB

a

Figure 15. Skin temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between pens within time (AM and PM) across seasons (Summer = SeptemberOctober; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size).

Figure 16. Rectal temperature (0C) of lactating Holstein dairy cows exposed to cooling systems between pens within time (AM and PM) across seasons (Summer = SeptemberOctober; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P ~.OOOI).

75

FIGURE 15: SKIN TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS WITHIN TIMES ACROSS SEASONS (SUMMER = SEPT-oCT; WINTER = FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46

PM

44

42 40 38 36 34 32 30

a

33.6:1: 0.39 b 30.3 :I: 0.56 .....--

SM DAlRYC

SK NS DAlRYB

30.2:1: 2.32

28

~

26

24 22 20 18 16 14 12 10

8 6 4 2

o

SM DAIRY C

SK UOF DAIRY B

n=Sample Size (a,b) Means within time with different superscripts differ (P ~ .01)

FIGURE 16: RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS WITHIN TIMES ACROSS SEASONS (SUMMER SEPT-OCT; WINTER FEB-MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

=

=

50 48

• ElAN

46 44

42 40 38 36 34 32 30

39.6 :I: 0.06

39.2 :t 0.1

40.0 :1:0.07

.--

a

~

~

n-193

na80

28 26

24 22 20 18 16 14 12 10

8 6 4 2

o

SM DAlRYC

SK UOF DAIRYB

SM DAlRYC

n=Sample Size (a,b,c) Means within time with different superscripts differ (P ~ .0001)

76

SK NS DAlRYB

Figure 17. The 305 days estimated milk production (kg) of lactating Holstein dairy cows exposed to cooling systems between dairies across seasons (Summer = SeptemberOctober; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feedline (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups did not differ (P ~.05).

Figure 18. 305 days estimated milk production (kg) of lactating Holstein dairy cows exposed to cooling systems between seasons (Summer = September-October; Winter = February-March) within dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups did not differ (P ~.05).

77

FIGURE 17: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN DAIRIES ACROSS SEASONS (SUMMER. SEPT-CCT; WINTER .. FEB.MARCH) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

18 17

.

Dairies

16 15 14 13 12 11 10 9 8

ii) 0

z c(

Ul

;:)

0

:c

t::.

lz

0

~

13,910 t 249

13,834 t 339

a

a

7

(J ;:)

6 5 4 3 2 1 0

0

0

II:: Q. ~

..J

i

11'1183

..-347 DAlRYB

DAlRYC

n=Sample Size (a) Means between dairies with same superscripts did not differ (P ? .05)

FIGURE 18: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN SEASONS (SUMMER SEPT· OCT; WINTER FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

=

=

18 17 ii) 0

z ~ ;:)

0

E

lz 0

1= (J ;:)

16 15 14 13 12 11 10 9 8

II:: ~

4

i

3 2 1 0

0

Q.

..J

WINTER

13784

t299

14.090 ±429

a

13,588 t456

a

14,111 t502

a

7

6 5

0

£':lSUMMER

DAlRYB

DAlRYC

n=Sample Size (a) Means between seasons with same superscripts did not differ (P ? .05)

78

a

Figure 19. The 305 days estimated milk production (kg) of lactating Holstein dairy cows exposed to cooling systems between pens within seasons (Summer = SeptemberOctober; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). The 305 days milk production of cows between treatment groups did not differ (P ~.05).

Figure 20. Temperature humidity index (THI), inside temperature vs. outside temperature of dairy housing within dairies across seasons (Summer = SeptemberOctober; Winter = February-March) in the subtropics. THI = temperature - [(0.55 (0.55 * humidity) * (temperature - 58)]. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). THI between treatment groups differed (P ~.0001).

79

FIGURE 19: THE 305 DAYS ESTIMATED MILK PRODUCTION OF LACTATING HOLSTEIN DAIRY COWS BETWEEN PENS WITHIN SEASONS (SUMMER = SEPT-OCT; WINTER = FEB.MARCH) ACROSS DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 18

17 16

o

G3SUMMER

14,568 14,062 :I: 955 13,705 14,111 :1:620 a :I: 698 :1:502 a II

WINTER

13,981 13,705 13 620 13,588 :I: 551 :I: 432 :I: 582 :I: 456 0

15

a

14 13

a

a

a

a

12

11 10

9 8 7 6

5 4 3 2 1

o

SM

-"S",K,--~=-_=

DAIRYC n=Sample Size (a) Means within seasons with same superscripts did not differ (P ~ .05)

FIGURE 20: THI (IN Y5. OUn OF DAIRY HOUSING WITHIN DAIRIES ACROSS SEASONS (SUMMER SEPT - OCT; WINTER = FEB-MARCH) IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 100 95

ElINSIDE

90 85 80

OUTSIDE

85:1: 0.39

b

78:1: 0.43

77:1: 0.26

82:1: 0.58 b

a

a

75 70

65 60

55 50

45 40

35 30

25 20

15 10

5

o DAlRYC

DAlRYB

n=Sample Size (aob) Means between conditions THI (In vs. Out) with different superscripts differ (P ~ .0001)

80

=

Figure 21. Temperature humidity index (THI), inside temperature vs. outside temperature of dairy housing within seasons (Summer = September-October; Winter = February-March) within dairies in the subtropics. THI = temperature - [(0.55 - (0.55 * humidity) * (temperature - 58)]. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n= Sample size). THI between treatment groups differed (P ~.0001).

Figure 22. Skin temperature (OC) of lactating Holstein dairy cows exposed to conditions sprinklers (Off vs. On) during the summer (September - October) in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P ~.0001).

81

FIGURE 21: THI (IN YS. OUT) OF DAIRY HOUSING WITHIN SEASONS (SUMMER. SEPT-OCT; WINTER .. FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS 100

95 90

~

85 80 75 70 65 60 55

50 45 40 35 30 25 20 15 10

5

o

r=:3INSIDE

OUTSIDE

86 t 0.57

83 t 0.69

b

78 :t 0.27"'-'

a

79 :t 0.44

a

ill

~

:~~~

.:: : .

:' ": .

{~~~

!

~:' .~: .:

~

79:t 0.75 76tO~62 ~

::=::'::'j

IL~

1::.:;.=:." :.;::

~~6 \-16

DAIRY B

b

i")"~

}~~

"::..':.:.

n

I

t~~~ ::::::

...._.....

p.-.;"ti

76:t0~33

~

'.i.l.":

:...•:.::.:.

i ~: ~

84:t 0.51

b

DAIRY C

DAJRYB

DAJRYC WINTER

SUMMER

n=Sample Size (a.b) Means between conditons THI (In vs. Out) with different superscripts differ (P ~ .0001)

FIGURE 22: SKIN TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS DURING THE SUMMER (SEPT-oCT) BETWEEN CONDIT10NS (SPRINKLER OFF ¥s. SPRINKLER ON) FOR PENS IN DAIRY B IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46 44 42 40 38 36 34

32

• ElSPRINKLER OFF

SPRINKLER ON

31.5:t 0.33 a

30

25.3:t 1.43

28 26 24 22 20 18 16 14 12

b

10

8 6 4 2

o

na118 UOF

SK

n=Sample Size (a,b) Means between conditions with different superscripts differ (P ~ .0001)

82

Figure 23. Rectal temperature (Oe) of lactating Holstein dairy cows exposed to conditions sprinklers (Off vs. On) during the summer (September - October) in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P :::;.05).

83

FIGURE 23: RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS DURING THE SUMMER (SEPT-oCT) BETWEEN CONDITIONS (SPRINKLER OFF YS. SPRINKLER ON) FOR PENS IN DAIRY B IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46

G:lSPRINKLER OFF

44

SPRINKLER ON 40.1 :t 0.08

39.2:t 0.11

42

a = ..:...:..:..: .. :-:

b r-

40 38 36 34

_·..~..l ·..•

38.6 :t 2.49 b

..

_:::::::::::

32 30 28 26 24 22 20 18 16 14 12 10

:~:~:~:~~:~

8 6 4 2

.~~~~

o

n-Ut UOF

SK n=Sample Size (a,b) Means between conditions with different superscripts differ (P ~ .05)

84

Figure 24. Skin and Rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (1 st 20 vs. 2nd 20 animal readings) without spray across seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korra1 Kool Bam with Galvanized Shade Structure over the feed manger (SK)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin and rectal temperatures of cows between treatment groups did not differ (P ~.05).

Figure 25. Skin and rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (1 st 20 vs. 2nd 20 animal readings) across seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = No Shade Structure over the feed manger (UOF)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment group's differed (P =:;;;.05) and rectal temperatures of cows between treatment groups differed (P =:;;;.0001).

85

FIGURE 24: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS ACROSS SEASONS BETWEEN CONDITIONS (1ST 20 va. 2ND 20 ANIMAL READINGS) FOR PEN SK IN DAIRY B IN HAWAII UNDER SAUDI KORAL KOOL BARN COOLING SYSTEM 50

48 46

" c:JFIRST _SECOND

44

42 40 38 36 34

32 30

38.9:t 0.1

a

29.0:1: 1.15

39.1 :1:0.13

a

29.8:1: 0.1

a

a

28 26

24 22 20 18 16 14 12 10

8 6 4 2

o SKIN TEMPERATURES

SK

RECTAL TEMPERATURES

n=5ample Size (a) Means between conditions with same superscripts did not differ (P ~ .05)

FIGURE 25: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS ACROSS SEASONS BETWEEN CONDITIONS (1ST 20 VI. 2ND 20 ANIMAL READINGS) FOR PEN UOF IN DAIRY B IN HAWAII UNDER NO SHADE STRUCTURE

50 48 46

CJFIRST _SECOND

44

39.3:1: 0.11 x

42 40 38 36 34

32

30.9:1: 0.15 a

39.7:1: 0.1 Y

32.1:1: 0.61 b

30

28 26 24

22 20 18 16 14 12 10

8 6 4 2

o

~U::··

na81

SKIN TEMPERATURES

n=59 UOF

n=Sample Size (a,b) Means between conditions with different superscripts differ (P ~ .05) (x,y) Means between conditions with different superscripts differ (P ~ ,0001)

86

na61

RECTAL TEMPERATURES

Figure 26. Skin and rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (1 st 20 vs. 2nd 20 animal readings) across seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = No Shade Structure over the feed manger (NS)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin and rectal temperatures of cows between treatment groups differed (P ~.05).

Figure 27. Skin and rectal temperature (0C) of lactating Holstein dairy cows exposed to cooling systems between conditions (Dry vs. Wet hair coat animal readings) across seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P :::;.05) and rectal temperatures of cows between treatment groups differed (P :::;.0001)..

87

FIGURE 26: SKIN AND RECTAL TEMPERATURES Of LACTATING HOLSTEIN DAIRY COWS ACROSS SEASONS BETWEEN CONDITIONS (1ST 20 YS. 2ND 20 ANIMAL READINGS) FOR PEN NS IN DAIRY B IN HAWAII UNDER NO SHADE STRUCTURE 50

48

46

DFIRST _SECOND

44

39.9:t 0.14

42

a

40 38

33.3± 1.98

36 34

a

40.1:t 0.11 a

31.7:t 2.36

a

32 30 28 26

24 22 20 18 16 14 12 10

8 6 4 2

o

0=4.9 SKIN TEMPERATURES

NS

n-67

RECTAL TEMPERATURES

n=Sample Size (a) Means between conditions with same supersctipts did not differ (P ~ .05)

FIGURE 27: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS DURING THE WINTER (FEB-MARCH) BETWEEN CONDITIONS (DRY YS. WET HAIR COAT ANIMAL READINGS) FOR PEN SM IN DAIRY C IN HAWAII UNDER MISTING COOLING SYSTEM

50 48 46

DDRY _WET

44

39.9:t 0.17

42

x

40

39.8:t 0.08

Y

38

36 34

32 30

30.0:tO.57

a

28.7:t0.38

b

28 26

24 22 20 18 16 14 12 10

8 6 4 2

o

n=24

0=24

n-100

118100

SKIN TEMPERATURES RECTAL TEMPERATURES SM n=Sample Size (a,b) Means between conditions with different superscripts differ (P ~ .01) (x,y) Means between conditions with different superscripts differ (P ~ .0001 )

88

Figure 28. Skin and rectal temperature (OC) of lactating Holstein dairy cows between times (AM = 800-900h; PM = 1300-1400h) for pen SK in Dairy B across seasons (Summer = September-October; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin and rectal temperatures of cows between treatment groups differed (P =:;.0001).

Figure 29. Skin and rectal temperature (OC) of lactating Holstein dairy cows between times (AM = 900-1000h; PM = 1200-l300h) for pen SM in Dairy C across seasons (Summer = September-October; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin and rectal temperatures of cows between treatment groups differed (P =:;.0001).

89

FIGURE 28: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN TIMES (AM = 8:00·9:00h; PM • 1300·1400h) FOR PEN SK IN DAIRY B ACROSS SEASONS 50 48

46 44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10

39.2:1: 0.05

32.0:1:0.17

a

39.2:1: 0.1

a

a

rt=233

n-aO

30.0:1: 0.56 b

8 6 4 2

o

SKIN TEMPERATURES

SK

RECTAL TEMPERATURES

n=Sample Size (a,b) Means between conditions with different superscripts differ (P < .0001)

FIGURE 29: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN TIMES (AM = 9:00·10:00h; PM = 1200-1300h) FOR PEN SM IN DAIRY C ACROSS SEASONS 50 48 46

~

W

It:

~

W

a. ~ w

I-

44 42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10

39.4:1: 0.04

a 30.2:1: 2.32 28.2:1: 0.27

a

a

8 6 4

2

o

n=237 _ •

na183

SKIN TEMPERATURES

SM

n=5ample Size (a,b) Means between conditions with different superscripts differ (P < .0001)

90

39.6:1: 0.04 b

Figure 30. Skin and rectal temperature (OC) of lactating Holstein dairy cows between times (AM = 1000-1100h for pen UOF; PM = 1400-1500h for pen NS) in Dairy B across seasons (Summer = September-October; Winter = February-March) in the subtropics. Treatment groups over the test period included: [Dairy B = No Shade Structure over the feed manger (UOF & NS2)]. All measurements are expressed as (mean ± SEM; n = Sample size).

Figure 31. Skin temperature (0C) of lactating Holstein dairy cows exposed to cooling systems between conditions (Black Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P < .01).

91

FIGURE 30: SKIN AND RECTAL TEMPERATURES OF LACTATING HOLSTEIN DAIRY COWS BETWEEN TIMES (AM = 10:00-11:00h FOR PEN UOF; PM = 1400-1500h FOR PEN NS) IN DAIRY B ACROSS SEASONS

50 48 46 44

42 40

40.0:1: 0.06

39.7:1: 0.07

38 36

34

32 30 28

33.6:1: 0.41

31.7:1: 0.41

26

24 22 20 18 16 14 12 10 8 6 4 2

o

:-:-hllll237:::-:

n..23-7:

SKIN n=Sample Size

RECTAL

SKIN

RECTAL PENNS

PEN UOF

FIGURE 31: SKIN TEMPERATURES OF "BLACK HAIR COAT COLOR" LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER .. SEPT-QCT; WINTER = FEB.MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46 44

CJSUMMER _WINTER

42 40 38

33.9

36

0 .57 35.0:1: a 0.67 b

34

==

31.7:t 0.33 32.9:t 0.83 30.0t O. a c:

28.8tO.41 d

32 30

28 26

24 22 20 18 16 14 12 10 8 6 4 2

o

r=150 SM DAIRYC

I

NS

..-70

1 SM

~

SK

n=Sample Size (a,b,c,d) Means between conditions with different superscripts differ (P ~ .01)

92

UOF NS DAIRYB

Figure 32. Rectal temperature (0C) of lactating Holstein dairy cows exposed to cooling systems between conditions (Black Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korra1 Koo1 Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P < .01).

Figure 33. Skin temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (Black/White Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korra1 Koo1 Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P < .01).

93

FIGURE 32: RECTAL TEMPERATURES OF "BLACK HAIR COAT COLOR" LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER .. SEPT-oCT; WINTER = FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOUNG SYSTEMS

50 48 46 44 42 40

OSUMMER _WINTER

39.6

39.3

to.06 t 0.06

32 30

Ill:

28 26

~

w

II..

~

....w

39.5

39.1

39.5

39.9

t 0.08 t 0.08 to.09 t 0.14 a b b c

b

r==

r

=150

0'!130

0=98

fO=73

p10

SK

UOF

NS

SM

34

t..

w

ab

40.1 t 0.1 a

ab

38 38

G'

39.5

to.95

24 22 20

18 16 14 12 10 8 6 4 2

0

SM

na70 SK

DAlRYC DAlRYB ~ n=5ample Size (a,b,c) Means between conditions with different superscripts differ (P ~ .01)

n-82

UOF NS DAlRYB

FIGURE 33: SKIN TEMPERATURES OF "BLACKIWHITE HAIR COAT COLOR" LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER .. SEPT-OCT; WINTER .. FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46 44 42

40 38 36 34

32 30

E1SUMMER _WINTER

33.0 :t 7.57 a

~

33.0

t 0.77

33.9 :t 0.95 a

31.0

~(II

28.6

:t 0.57

to.67 b

c

29.1 :t 1.13

32.8 :t 1.53

a

c

28

26 24 22

20

18 16

14 12

10 8 6 4 2

o

.~ :=~:::::=::·1

::::=::=j

11~j

SM SK UOF NS SM SK DAlRyC ~ ~ n=Sample Size (a,b,c) Means between conditions with different superscripts differ (P ~ .01 )

94

UOF DAlRYB

NS

Figure 34. Rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (Black/White Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P < .01).

Figure 35. Skin temperature (OC) oflactating Holstein dairy cows exposed to cooling systems between conditions (White Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Bam with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Skin temperatures of cows between treatment groups differed (P < .01).

95

FIGURE 34: RECTAL TEMPERATURES OF "BLACKlWHITE HAIR COAT COLOR" LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER = SEPT-oCT; WINTER. FEB.MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46 44

E w

II::

~

w

a.

::I!

...w

42 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4

E1SUMMER _WINTER

39.6 39.4 t 0.08 t 0.23 b

b

40.1 t 0.2 iI

40.2 t 0.19

a

39.4 to.14

38.9 to.17

b

e

SM

SK

39.3 39.7 to.14 to.16 b

2

a

n-17

o

SM SK DAIRYC n=SampleS~

UOF DAlRYB

NS

DAlRYC

(a,b,e) Means between conditions with different superscripts differ (P

NS UOF DAIRYB

=" .01)

FIGURE 35: SKIN TEMPERATURES OF "WHITE HAIR COAT COLOR" LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER = SEPT·OCT; WINTER = FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOLING SYSTEMS

50 48 46

DSUMMER II!IIIWINTER

44

42 40 38 36 34

32 30 28 26 24

31.7 30.2 t 0.68 t 1.07 b

e

33.3

t 1.2 a

31.6 to.55

r==:=s

a

31.2 27.9 t 1.39 t 1.06 a b

22 20 18 16 14 12 10 8 6 4 2

o

SM DAlRYC n=Sample Size

n"37 SK

UOF DAlRYB

NS

SM

SK

DAlRYC

(a,b,e,d) Means between conditions with different superscripts differ (P =" .01)

96

.,.20

111'13

UOF NS DAIRYB

Figure 36. Rectal temperature (OC) of lactating Holstein dairy cows exposed to cooling systems between conditions (White Hair Coat Color) within seasons (Summer = September-October; Winter = February-March) across dairies in the subtropics. Treatment groups over the test period included: [Dairy B = Saudi Korral Kool Barn with Galvanized Shade Structure over the feed manger (SK); No Shade Structure over the feed manger (UOF) and (NS)]; [Dairy C = Misting System under Aluminum Shade Structure (SM)]. All measurements are expressed as (mean ± SEM; n = Sample size). Rectal temperatures of cows between treatment groups differed (P < .01).

97

FIGURE 36: RECTAL TEMPERATURES OF "WHITE HAIR COAT COLOR- LACTATING HOLSTEIN DAIRY COWS WITHIN SEASONS (SUMMER. SEPT-QCT; WINTER. FEB-MARCH) WITHIN DAIRIES IN HAWAII UNDER DIFFERENT COOUNG SYSTEMS

50 48 46

44 42 40 38 36

GJSUMMER _WINTER

39.6 :I: 0.11

b

39.4 40.1 :I: 0.15 :I: 0.16

b

40.1 :I: 0.18

a

a

UOF DAlBYB

NS

39.6 :I: 0.14

39.1 :I: 0.12

ab

c

39.3 :I: 0.16 be

39.1 :1:0.2



34

32 30 28 26 24 22

20

18 16 14 12 10 8 8 4

2

o

In~5 10=32 SM DAlRYC

SK

n-34 SM

111'20 SK

DAlRYC

n=Sample Size

(a,b.c) Means between conditions with different superscripts differ (P ~ .01)

98

111'13

UOF NS DAIRYB

CHAPTER 3 SUMMARY AND CONCLUSION

3.1 SUMMARY AND CONCLUSION In summary, the results of this study demonstrated the importance of cooling dairy cattle with appropriate cooling systems in hot humid climates.

Heat stresses due to

environmental factors such as solar radiation and humidity have shown to increase RR, ST, RT, THI levels and cause alteration slightly in milk production during these experimented trials. These results are similar to research done by (Ingraham et al., 1974; Roman-Ponce et al., 1976; Hahn, 1985; Johnson, 1987; Turner, 1998; Bucklin et al., 1991; Shearer et aI., 1991; Armstrong, 1994; Podmanicky et al., 2002; West et al., 2002). In conclusion, results for the reported research are as followed: 3.1.1

Experiment 1

1. The results suggest that that the cooling systems at Dairy B [SK = Saudi Korral Kool Bam with Galvanized Shade Structure; UOF

=

Universal Oscillating Fogger

system blowing into a Galvanized Shade Structure 10-feet away] was the most effected types of cooling systems in lowering RR followed by Dairy C [SF = 36inch Shaffer Fans under Aluminum Shade Structure; SM = Misting System under Aluminum Shade Structure] and lastly Dairy A [S

=

Pens with Zinc Corrugated

Shade Structure]. 2. Dairy B reported the most effective cooling systems in reducing RR during the experimented periods.

99

3. PM experimented time periods (AM vs. PM) reported higher increase in RR for all experimented dairies. 4. All RR values reported were above the normal temperature ranges during the experiment period for all dairies except for Dairy B pen SK during the winter period which reported RR of(47 ± 0.46). 5. Dairy B produced the most 305 days estimated milk production followed by Dairy C and lastly Dairy A. 6. THI levels reported were above 72 indicating that the animals were in the moderate to stress level conditions. Animals in this experiment gained more heat from the environment then they could lose which resulted in heat stressed animals. 3.1.2

Experiment 2

1. Dairy B pen SK and Dairy C pen SM reported the most effective cooling systems in reducing ST and RT during the experimented periods. 2. All ST and RT values reported were above the normal temperature ranges during the experiment period for all dairies except for Dairy B pen SK which reported values within the normal skin and rectal temperatures ranges. 3. No significant differences were reported for 305 days estimated milk production during the experiment which suggests that Dairy B and Dairy C produced similar amounts of milk production. 4. THI levels reported were above 72 indicating that the animals were in the moderate to stress level conditions. Animals in this experiment also gained more

100

heat from the environment then they could lose which resulted in heat stressed animals. 5. Skin and rectal temperatures values reported to be lower when additional sprinkler system above the feed manger was mounted. The sprinkler systems allowed skin and rectal temperatures values to be within the normal temperature ranges for dairy cattle. 3.1.3

Experiment 3

1. Skin and rectal temperatures between the (l st 20 vs. 2nd 20 animal readings) did not differ for pen SK and pen NS. However, for pen UOF significant differences were observed in ST readings across the seasons (P ::;.05). The results further suggest that the increases in skin and rectal temperatures may have been due pen UOF having no shade structure over the feed manger and the distance the animals in pen NS had to walk from the milking parlor to an available space at the feed manger. 2. All skin and rectal temperatures values (1st 20 vs. 2nd 20 animal readings) during this experiment were just slightly above the normal temperature ranges for dairy cattle. 3. The results suggest that the wet-hair-coat animals were significantly cooler then the dry-hair-coat animals for skin and rectal.

4. All skin and rectal temperatures values (wet vs. dry hair coat animals) during this experiment were just slightly above the normal temperature ranges for dairy cattle.

101

5. PM experimented time periods (AM vs. PM) reported higher increases in ST and RT for all experimented dairies except for pen SK which reported lower ST values during the PM periods. 6. Skin and rectal temperatures between hair coat colors were observed and demonstrated similar results to skin and rectal temperatures in experiment 2. Overall environmental modifications such as cooling systems are essential in helping to alleviate heat stress on dairy cattle during hot weather conditions, which in tum can provide increased cow comfort. The combined results of this study indicate the importance and usefulness of cooling systems to aid in increasing productivity and overall comfort in lactating Holstein dairy cows under heat stress conditions in Hawaii. Further field studies should be done to determine the economical feasibility of additional environmental modifications.

102

APPENDIX A DAIRY A, B, & C LAYOUT PICTURES

103

DAIRY A

PEN 2

PEN 1

PEN 4

PEN 3

104

DAIRY B

PEN SK

PEN UOF

PEN UOF

PEN NS

DAIRY C

PEN SM PEN SF

J06

LITERATURE CITED

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107

Bond, J., and R E. McDowell. 1972. Reproductive performance and physiological responses of beef females as affected by a prolonged high environmental temperature. J. Anim. Sci. 35:820. Bouraoui, R, M. Lahmar, A Majdoub, M. Djemali, and R Belyea. 2002. The relationship of temperature-humidity index with milk production of dairy cows in a Mediterranean climate. Anim. Research 51 :479. Bray, D. R, and J. K. Shearer. 1988. Environmental modifications on Florida dairies. Proc. ofthe 25 th Annu. Florida Dairy Production Conf., p. 52. Gainesville, FL. Bray D. R, D. K. Beede, R A Bucklin, and G. L. Hahn. 1992. Cooling, shade, and sprinkling. Large Dairy Herd Management, p. 655. University of Florida and USDA Gainesville, FL and Clay Center, NE. Bray, D. R, R A Bucklin, R Montoya, and R Giesy. 1994a. Means to reduce environmental stress on dairy cows in hot humid climates. Proc. 3rd Int. Dairy Housing Conf., p. 589. Orlando Florida. Bray, D. R, R A Bucklin, R Montoya and R Giesy. 1994b. Cooling methods for dairy housing in the Southeastern United States. ASAE paper No. 94-4501. Atlanta,

GA Brouk, M. J., J. F. Smith, and J. P. Hamer. 1999. Performance oflactating diary cattle housed in a four-row freestall bam equipped with three different cooling systems. Dairy Day, p. 23. Kansas State University. Brouk, M. J., J. F. Smith, and J. P. Hamer, III. 2001. Effectiveness of fan and feedline sprinklers in cooling dairy cattle housed in 2-or4-row freestall buildings. Proc. 6th Int. Symposium on Livest. Environment, p. 15. Louisville, KY. Brouk, M. J., J. F. Smith, and J. P. Hamer, III. 2003. Effect of utilizing evaporative cooling in tiestall dairy barns equipped with tunnel ventilation on respiration rates and body temperature oflactating dairy cattle. Proc. of the 5th Int. Dairy Housing Conf., p. 312. Fort Worth, Texas. Brown-Brandl, T. M., J. A Nienaber, R A Eigenberg, T. L. Mader, J. L. Morrow and J. W. Daily. 2003. Relative heat tolerance among cattle of different genetics. Proc. of the 2003 ASAE Annu. Int. Mtg., p. 1. Las Vegas, Nevada. Bucklin, R A, D. R. Bray, and D. K. Beede. 1988. Methods to relieve heat stress for Florida dairies. Cooperative Extension Service, University of Florida, Institute of Food and Agric. Services - Circular 782.

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Bucklin, R. A, L. W. Turner, D. K. Beede, D. R. Bray and R. W. Hemken. 1991. Methods to relieve heat stress for dairy cows in hot humid climates. Appl. Engineers in Agric.7 :241. Bucklin, R. A, G. L. Hahn, D. K. Beede, and D. R Bray. 1992. Physical facilities for warm climates. Large dairy herd management, p. 609. Am. Dairy Sci. Association, Champaign, IL. Bucklin, R. A, R. W. Bottcher, G. L. Van Wicklen, and M. Czarick. 1993. Reflective roof coatings for heat stress relief in Livest. and poultry housing. Appl. Engineering in Agric. 9:123. Buffington, D. E., A Collazo, W. W. Thatcher, and T. C. Skinner. 1978. Air conditioning and shade. Large dairy herd management, p. 909. Florida. Buffington, D. E., A Collazo-Arocho, G. H. Canton, D. P. H., W. W. Thatcher and R. J. Collier. 1981. Black globe-humidity index (BGHI) as comfort equation for dairy cows. Transaction ofthe ASAE 24:711. Buffington, D. E., R. J. Collier, and G. H. Canton. 1983. Shade Management systems to reduce heat stress for dairy cows in hot, humid climates. ASAE Paper No. 824061 St Joseph, MI. Calamari, L., and P. Mariani. 1998. Effects ofthe hot environment conditions on the mail milk cheese making properties. Zoot. Nutr. Anim., 24:259. Cannon, W. B. 1932. Wisdom of the Body. W.W. Norton and Co., New York. Canton, G. H., D. E. Buffington, and R. J. Collier. 1982. Inspired air cooling for dairy cows. Transaction of the ASAE 25:730. Cappa, V., P. Vazhapilly, M. G. Maianti, R. Lombardelli, and E. Frazzi. 1989. Effect of environmental variations (microclimate) on the performance of diary cows. Sci Tech. Latt.-Cas. 40:98. Chamberlain, A 1989. Milk Production in the Tropics, p. 92. British Library Catalog.

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i

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