The influence of a non-homogeneous temperature field on dairy cows

摘要

The horizontal distribution of temperature in a dairy cow housing space is not too homogeneous, especially in the summer season. Air flow (at the rate of speed of 1.9 m/s and the temperature of 22 deg C) was simulated on various body parts of a dairy cow (the shoulder and lumbar parts) in an air-conditioned stable and under the temperature of 25 deg C (with temperature differences of 3 K) and 27 deg C (with temperature differences of 5 K). The ventilation lasted for 30 minutes. Before the beginning of the ventilation and then, after 10 minutes, and finally 5 minutes after the end of the ventilation the surface of the dairy cow was screened by an infra-red camera. Taken snaps have shown a considerable sensibility of the cow at the ventilation on the lumbar joint in the temperature difference of 5 K. After 30 minutes of the cooling there were cooled down the directly cooled body parts. During ventilation of colder air on the shoulder region was the cool down 0.5 K (differences 3 K), alternatively 0.1 K (differences 5 K). In the case of ventilation on the lumbar region was the cool down 0.7 K alternatively 1.7 K. Tendencies to change thermoregulation occurred during the ventilation.