Effects of temperature, humidity and season on the cortisol levels in Holstein Friesian

Abstract

Temperature and humidity are an important factor in dairy cow management, stress, and milk production. The objective of this study was to investigate the changes in cortisol concentration of Holstein Friesian dairy cows influenced by environmental temperature changes and humidity in the air during different seasons in Lamphun Province. The cortisol hormone was determined using the Sandwich ELISA method, with standard values of 0, 0.039, 0.078, 0.156, 0.315, 0.625, 1.25, 5, and 10 ng/ml. Cortisol concentrations have been determined in cow fecal extract samples. The results showed average temperature was 28.16°C, relative humidity was 34.36%, THI was 72.40 %, and cortisol was 12.84 ng/ml. The average cortisol concentration was 16.96 ± 7.83 ng/ml during a rainy season, which was higher than the winter (7.94 ± 3.01 ng/ml). Since measured inside the dairy farm. The height was found during the rainy seasons of August and October, when the measured humidity was 52.29 and 54.19%, respectively, and the temperature in winter has more instability in the weather before entering the summer, influencing the concentration of cortisol hormone in the winter to be higher. all through winter, as well as high humidity in January, when the humidity is approximately 52.71%. Also, cortisol concentrations were lowest in the summer, at 7.03 ± 2.93 ng/ml. The results showed a relationship between temperature, humidity, and season on cortisol concentration in Holstein Friesian. The average cortisol concentration to air temperature correlated by 0.17 (P<0.05). And the average amount of cortisol to Relative humidity, season, and THI correlated were 0.435, 0.543, and 0.347 respectively (P<0.01).  Therefore, this study found temperature, relative humidity, and season-influenced cortisol concentration indicated stress in Holstein Friesian.