Balancing Diets for Dairy Cattle during Heat Stress Conditions

A well-known dairy scientist once wrote that "compared with an effective environmental management system, manipulation of the cow's diet specifically for heat stress will have a relatively small effect on productivity" (Beede and Shearer, 1992). Indeed many dietary adjustments made during heat stress feeding are to compensate for reduced feed intake or to maintain physiologic homeostasis in the cow. Yet despite advances in cow cooling, barring total environmental control such as air conditioning, some reduction in cow performance will occur during hot weather. Once economically realistic attempts have been made to modify the cow's environment, then dietary alterations become necessary.