Influence of Water Temperature and Heat Stress on Drinking Water Intake in Dairy Cows

摘要

Grazing animals are exposed to heat stress and there should be conditions to facilitate water intake. Three experiments were carried out to determine the relationship between water intake, water temperature, and heat stress for Holstein pastured dairy cows. Experiment 1: Drinking behavior of 13 cows was evaluated (for 3 consecutive days) and four time periods were established according to the temperature humidity index (THI): (H1:05:00 to 10:59 h, H2:11:00 to 16:59 h, H3:17:00 to 22:59 h, and H4:23:00 to 04:59 h). The highest mean percentage of drinking bouts (53.2%) was registered in H2 (THI: 74.91 to 83.95). Drinking bout means among time periods were different (p 0.05). Recorded water intake in T1 (18 L ) was lower than in T2 (35.9 L ), although body heat dissipation was higher (T1 = 672.64 kJ d-1, T2 = 620.76 kJ d-1).