May Mitigation

Erica Sayles |  May 17, 2021

Spring has arrived, and as we know April showers bring May flowers… and heat stress. While you may have perfect weather to get seed in the ground, the weather is starting to become a challenge for dairy cows. Heat stress causes losses on farms in a variety of ways, from decreased production to reproductive performance issues, and even increased health problems.

Battling low production, increased lameness, low pregnancy rates and much more is not on anyone’s to-do list this summer. The solutions are not as simple as feeding them more, breed them more, or treat them more. We can do much better than that. Reduced dry matter intakes, increased respiratory rates, and lowered milk yields all occur after a heat stress event has already happened. 

Once signs of heat stress are observed in cows, the losses have already begun. So prevention should be step one. 


Key components of mitigating heat stress are: 

➔ shade 

➔ ventilation 

➔ water 

Looking at both milking and dry cows, ensure that these main areas are covered. 


If cows are on pasture, give them access to a shed or some form of protection from the sun. Not only is it hot but they run the risk of sunburn. Ensure fans are on and moving air through the barn. Get down to the cow level and see if the air is moving through them or over them. You can not properly analyze airflow from the feed alley. Look for pens that may be wind shadowed from walls or other buildings and provide them with fans. Finally, go through all pens from calves to lactating animals and regularly clean out their water bowls while ensuring they have proper flow rates. 

Temperature humidity index (THI) is a great way to measure heat stress in housed cattle. It is also a good way to help you predict what will be coming based on the weather forecast so you can prepare. A chart in both Fahrenheit and Celcius can be found here: 

Start those fans up and leave a brush by the water bowls because the season of heat stress has started and will be here for a while. If you have questions about the effectiveness of your heat mitigation strategy from fan placement to water space feel free to reach out to anyone on the Parion dairy team.