Heat stress adversely affects dairy cows in a variety of ways. A cow suffering from heat stress, for example, produces less milk, conceives less often, and is at a greater risk of contracting a range of debilitating and even deadly diseases. The severity of the effects directly related to heat stress vary significantly by climate, with estimated production losses at dairies without cooling ranging from 403 pounds per cow per year in Wisconsin to almost 4,000 pounds per cow per year in Florida. Heat stress can also have a major effect on reproduction cycles. Clearly, as global temperatures increase and dairies expand to meet a growing demand, the costs of heat stress and the need to mitigate it will increase as well. Fortunately, the effects of heat stress can be reduced by implementing properly designed and operated ventilation systems and employing effective cow cooling strategies. A 2003 analysis found that providing dairy cows with an optimal level of cooling reduces the total cost of heat stress and its mitigation by an average of 43% across the US, as compared to if no cooling measures were taken.
To help producers better understand the costs associated with heat stress and the measures that can be taken to alleviate it, UW-Madison PhD Student Ian Atkins, UW Madison Department of Biological Systems Engineering Dr. Christopher Choi and UW-Extension Dairy Engineer (professor emeritus) Brian Holmes provides Dairy Cooling: the Benefits and Strategies summary, which heat stress characteristics and their effects in more detail and also the various systems and strategies now available for heat stress relief.