Effect of Heat Stress on Milk Production and Immune Function of Karadi Cows in Sulaymaniyah Governorate.

Environmental factors such as heat stress have a considerable impact on animal productivity, health, and well-being. Our objectives were to measure the physiological response to heat stress in Karadi cows, and to measure the production level of those cows. Sixteen multiparous Karadi cows were randomly assigned to 1 of 2 treatments: heat stress (HT, n = 8) or cooling (CL, n = 8), depending on the yield of mature equivalent milk (HT: 1.72 ± 0.23 kg; CL: 1.83 ± 0.23 kg) of the daily lactating. The average HT and CL cow parity were 3.5 ± 0.4 for each, and the average body weight of HT and CL cows was 197 ± 5.6 kg and 200 ± 5.6 kg, respectively. Rectal temperature (RT), skin temperature (ST), and respiration rate (RR) were recorded once daily (1400 h). Dry matter intake, water intake, milk yield, and milk composition were recorded daily, as well. Blood sample was collected three times; the beginning, the mid, and the end of the study for white blood cell (WBC) count. Cows from the HT treatment possessed a higher rectal temperature, skin temperature, and respiration rate in comparison to the cooling system. Compared with CL cows, HT cows produced less milk, solids-nonfat (SNF), protein, and lactose. However, no treatment effect was observed for concentrations of milk fat. Relative to CL cows, HT cows consumed less dry matter intake and consumed more water intake. Regarding WBC count, HT cows tended to have more WBC cells compare to CL cows. Additionally, HT cows have a greater number of neutrophils and monocytes compared to CL cows. No effect of treatment was observed for number and percentage of lymphocytes, percentage of neutrophils, and percentage of monocytes. Thus, heat stress negatively affects the milk production and immunity of Karadi cows. [ABSTRACT FROM AUTHOR]