Effect of Air Humidity on Cow’s Milk Yield during Grazing

Air humidity and quality affect milk yield in Holsteinized Red Steppe cows, but this effect depends on the geographical location. The authorsanalyzed an eight-year period to identify the exact correlation between the air humidity and the physiological status of cows. The average daily yield per herd was determined in June, July, August, and September, and then the days with minimal and maximal yields were investigated for air humidity. The average air humidity remained almost the same over the entire study period, amounting to 66.5% for the maximal yield and 65.9% for the minimal yield. On the minimal-yield days in May, the yields exceeded those obtained on the maximal-yield days in other months while the difference between the yields was minimal (297.2 kg). Under pasture conditions, air humidity had no significant effect on milk yield. In May, June, and August, high air humidity correlated with minimal daily yields (4.6, 6.0, and 0.7%, respectively). In July and September, the air humidity on maximum-yield days was higher than on minimum-yield days by 0.4 and 3.2%, respectively. On average, the air humidity on maximum-yield days was higher by 0.6%. Across the entire study period of 1,200 days, the above-average daily yield was obtained on 291 days and amounted to 13,008.3 kg whereas the below-average yield was 12,346.8 kg for 271 days (22.6%), the overall difference being 661.5 kg. The annual milk loss during the grazing period amounted to 54.8 tons.