Hot weather can bring a long list of problems for dairy producers. When cows are heat stressed, they eat less, produce less milk, have reduced immune function and higher SCC, and show reduced fertility. A spike in lameness often follows the hot season. In severe heat waves, cows can even die. In addition to the economic burden, the discomfort from heat stress also reduces animal welfare. UW-Madison Extension provides information on cooling cows housed in barns, where they are shaded from gaining heat from direct sun exposure.

Heat stress occurs when an environment impacts the ability of a cow to get rid of body heat. Cows need to be raised in an environment where temperatures are within their thermoneutral zones to achieve their maximal genetic potential. Failures to establish adequate environmental temperatures can dramatically alter behavior, health, and productivity of cows.

Dairy producers often struggle to quantify the impact of heat stress on their operations. The ability to use dairy management records to identify seasonal trends is critical to assess potential heat stress related losses. Diving into a dairy’s herd management software can help a producer quantify where the losses are occurring and, with some easy calculations, determine the profitability of investing in cow cooling measures.

Hot summer weather can be hard on feed ingredients and total mixed rations (TMRs). It is vital that feed quality and aerobic stability be maintained during this challenging season. Doing so will minimize nutrient losses while optimizing cow intakes which are often compromised due to heat stress challenges.

Dairy cattle are susceptible to heat stress during much of the summer. Dietary adjustments can help maintain nutrient intake and production.