Authors : Correa-Calderon A , D. V. Armstrong , D. E. Ray , S. K. DeNise and R. M.
Abstract: Thirty-seven Holstein and 26 Brown Swiss dairy cows were allotted to three treatments to evaluate the effects of two cooling systems on their productive and reproductive response. The treatment control had access to only shade (C). A second treatment was under a spray and fan cooling system (S/F) and the third treatment was cooled with a evaporative cooling system Korral Kool? (KK). The maximum temperature-humidity index recorded was from 73 to 85. Milk production of Holstein cows in S/F (39.1 kg/d) and KK (37.9 kg/d) groups was increased (P<.05) compared to C (31.0 kg/d). No treatment differences in milk production were observed in Brown Swiss cows (P> 05). Protein percentage in milk was higher (P<.05) in C (3.3%) and S/F (3.3%) groups compared to KK (3.1%) in Brown Swiss cows. Fat percentage in milk was increased by both cooling systems in Brown Swiss cows. Pregnancy rate in Holstein cows was improved (P<.05) in the groups under the cooling systems 75% (S/F) 58.3% (KK) compared to 0% in C group, however this effect was not observed in Brown Swiss cows where control group had a significantly (P<.05) higher pregnancy rate than S/F group. These results demonstrate that both cooling systems are an effective microclimatic modifications to increase productive and reproductive performance of Holstein cows during summer in hot-dry climates. Conversely, Brown Swiss cows were better adapted to heat stress and did not benefit from either cooling system.
Correa-Calderon A , D. V. Armstrong , D. E. Ray , S. K. DeNise and R. M. , 2005. Productive and Reproductive Response of Holstein and Brown Swiss Heat Stressed Dairy Cows to Two Different Cooling Systems . Journal of Animal and Veterinary Advances, 4: 572-578.