Understanding the Impact of Heat Stress on Dairy Cows

As temperatures rise during the summer months, heat stress becomes a critical concern for dairy producers. Not only does it affect cow comfort, but it can also lead to significant decline in productivity, reproductive performance and overall herd health.  Understanding the impacts of heat stress is essential to implementing effective management strategies.

Heat stress costs the dairy industry over $897 million annually in losses attributed to decreased performance, increased mortality, and decreased reproduction (St. Pierre et al., 2003). It is caused by a number of factors, including air temperature, humidity, wind speed, and solar radiation. Cattle experience heat stress when they cannot physically cope with their environmental conditions. Producers know heat stress can have severe impacts on cattle, but what exactly happens to a cow experiencing heat stress?