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Timestamp: 2019-04-19 06:32:43+00:00

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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.
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).
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.
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.
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.
(Stott, 1981). Readjusting to the homeostasis mechanism or acclimating to any situation is vital for the survival and well-being of the animal.
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).
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).
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.
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).
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.
clouds have shown to restrict radiant and evaporative cooling.
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.
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).
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.
systems and hormonal treatments that may help to restore normal fertility and maximize reproductive performance.
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).
digestive disturbances, particularly rumen acidosis that can lead to problems like laminitis.
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.
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.
normal body temperatures and metabolic homeostasis (Lee, 2003).
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.
lower productivity levels and metabolic rates than the Bas taurus species (Mount, 1979; Chamberlain, 1989).
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.
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).
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.
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.
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).
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.
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.
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.
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).
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.
respiration rates more than a north to south orientation (60.5 vs. 66.9).
12 ft and structures wider than 40 ft should be at least 16ft or more."
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."
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.
minute intervals depending on the temperature. Mechanical ventilation is a critical factor that can help to improve cow comfort during heat stress conditions.
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.
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.
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.
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.
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.
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).
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.
research and to evaluate and find the most effective cooling systems for dairy cows in Hawaii.
Heat stress in subtropical and tropical areas is an important factor and a major concern that dairy producers face everyday.
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).
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.
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).
respiration rates, skin temperatures, rectal temperatures, 305 days estimated milk production and temperature humidity index.
Committee (IACUC) approved this research protocol (number 01-012) on May 29th , 2001.
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.
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.
(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.
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).
production was obtained for each cow from DHI records.
March 2003] by counting flank movements over a 60 second period.
(db) is dry bulb and (rh) is relative humidity (National Academy of Sciences, 1971; West, 1999).
experimented pens (sample size n).
(National Academy of Sciences, 1971; West, 1999).
1000h); PM (1200-1300h)] during the test period [Summer Winter = February-March 2003].
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.
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).
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.
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.
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.
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).
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.
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.
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.
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.
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).
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.
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.
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.
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.
2.4.2.1 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.
between pens within the summer and winter seasons across dairies.
summer and winter seasons across dairies.
observed between Dairy B pens UOF and NS.
.05) between Dairy B pens SK and UOF.
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.
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.
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.
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.
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.
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.
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.
yield Flamenbaum, 1986; Igono et al., 1987; Strickland et al., 1989; Bucklin et aI., 1991; Turner et al., 1991; Brouk et al., 2001).
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.
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.
.05) observed between skin and rectal temperatures.
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.
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.
increased heat loss from the body surfaces of cattle when wetting frequency and airflow rates were increased.
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).
maintaining ST at similar values in respect to the experimented times.
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).
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.
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.
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.
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).
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).
z i a:: w Q.
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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).
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)..
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).
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).
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).
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).
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).
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.
Shade Structure]. 2. Dairy B reported the most effective cooling systems in reducing RR during the experimented periods.
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.
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.
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