GRAZING BEHAVIOR OF DAIRY COWS WITH ACCESS TO SHADE

Abstract

The study aimed to test the hypothesis that access to shade modifies the grazing behavior of dairy cows. During the warm (May) and cool (October) seasons of 2017, 18 lactating New Zealand Holstein cows were kept under grazing divided into two treatments, 1) with access to shade and 2) without access to shade. Their behavior was recorded every ten minutes during five days in each experimental phase. The response variables were the times of ruminating standing, ruminating lying, total rumination, resting standing, resting lying, total resting, and grazing. The data were classified as daytime (07:00 to 19:00) and night (19:00 to 07:00); for the daytime analysis, the information was grouped into four periods, T1 (07: 00-10: 00 h), T2 (10: 00-13: 00 h), T3 (13: 00-16: 00 h), and T4 (16: 00-19: 00 h). In the warm season (May), the cows with access to shade grazed 16% less (p <0.05) in the periods with the higher temperature-humidity index (ITH) and solar radiation, moments in which they remained in the shade. During the cool season (October), at moments of higher ITH and solar radiation, the cows with access to shade ruminated standing 44% longer (p <0.05), their total ruminating time was 30.7% longer (p <0.05), while cows without access to shade increased (p <0.05) their resting time standing by 22.5%. Access to shade did not change (p> 0.05) the ruminating time standing or lying, resting standing, or lying during the 24 h in both seasons. The cows preferentially used the shade as a shelter at night. Access to shade modified the behavior of dairy cows grazing in the temperate climate of Mexico.