Group 5
Twelve multiparous mid lactation cows were assigned to one of two studies in January or June of 2004. Animals were balanced for parity and assigned to one of two environmental chambers at the University of Arizona, William J. Parker Research Complex. Environmental treatments consisted of one thermal neutral environment (8-15°C, 8-40% humidity) and two heat stressed environments 1) 30-40°C, 8-40% humidity and 2) the same heat stress conditions with the addition 4 h of solar radiation at 600 watts/h/m2 from 1100 to 1500 h). Animals were provided