Figure 1.

Temporal patterns of minimum (min) and maximum (max) temperature-humidity index (THI) during the experimental period. Mean daily maximum temperature, minimum relative humidity, and maximum THI were 37.0 °C, 31.9%, and 83.4 for HS group and 27.3 °C, 44.9%, and 75.7 for CL group, respectively. THI categories developed for high-yielding lactating cows by Zimbelman et al. (2009) were used: thermal neutral (<68), heat stress threshold (68 to 71), mild-to-moderate heat stress (72 to 79), moderate-to-severe heat stress (80 to 89), severe heat stress (90 to 98), and extremely severe heat stress (>100).