Dear Dairy Cows: Summer is Almost Over!

Dairy farmers use fans and misters to keep cows cool durning summer

August in Pennsylvania is often hot and humid, with temperatures creeping up to the high 90s and humidity above 90 percent. When temperatures get that hot, we move indoors for air conditioning or we cool down with a trip to the pool, river or waterpark.

How do animals handle such extreme heat? Weighing an average of 1,400 pounds, dairy cows produce a large amount of body heat, which means cows get hot faster than humans, especially if they are in a group. Their ideal temperature is between 40-65 degrees, which means Pennsylvania cows love winter!

What should the dairy farmers of Pennsylvania do to keep their cows cool during summer? There are several different options – all of them make smart use of technology and innovation.


Seeking shade from trees and buildings is a cow’s easiest option when living on pasture. For cows that live in barns, farmers have gotten innovative. Most barns have sides that open (sort of like windows) to provide ventilation. Instead of a hard sidewall, there is a curtain. The curtain rolls up or down depending on the temperature, keeping the barn cool and the cows comfortable.


A box fan in a window helps cool off a room in your house, but in a barn, you need much more than a box fan. Farmers mount huge fans (4-6 feet in diameter or larger) over the cows’ feed and rest area. These fans turn on automatically when the temperature hits a certain point, making sure the cows are cooled with a comforting breeze.


Many farms combine fans with misters. These are installed above or near the fans and mist the cows with water. The misters will work in coordination with the fans, turning on automatically when temperatures climb. The water on the cows evaporates with the help of the fans, allowing the cows to cool down instantly.

Tunnel Ventilation

Have you ever opened a window or door at both ends of your house to get a cross-breeze? That same concept is applied to tunnel ventilation. With this type of barn, large fans are stacked on top of each other at one end of the barn. The fans blow air outside of the buildings, creating a vacuum-like effect. This causes air to move through the barn, dropping the inside temperature by about 15 degrees!

Take heart dairy cows – autumn is almost here, which means winter, the perfect cow weather, is just around the corner. No fans, misters or shades needed!

Read how dairy farmers in other parts of the U.S. keep their cows cool from our friends at DairyGood!