Current Progressive Dairy digital edition

1209 PD: Summer-ize rations to avoid heat stress production loss

Lori Stevermer Published on 05 August 2009

As temperatures rise, feed intake in dairy cattle tends to decline.

Avoiding heat stress will help cows stay on feed and thus maintain productivity and keep more milk in the tank.

Producers can alleviate the effects of heat stress on their herd, not only by changing environmental conditions but by “summer-izing” rations as well, explains Dan Schimek, dairy nutritionist for Hubbard Feeds Inc.



“When temperatures go above 80°F, we start to see feed intake reduction, yet a cow’s energy needs increase as she’s trying to dissipate heat,” Schimek says. “Cows sweat 10 percent of what humans do so it takes more energy for them to cool themselves.”

Some quick tips to summer-ize your rations include:

• Add fat to the diet to make it more energy dense. Fat contains 2.25 times more energy than carbohydrates so adding such products to the diet helps maintain energy intake as dry matter intake decreases.

• Fiber digestion increases the amount of heat produced by the cow internally, as compared to protein and carbohydrates. Therefore, making sure that adequate, but not excessive, amounts of high-quality fiber are being fed can help alleviate heat stress.

• Increase mineral content – specifically potassium and sodium – to help replace minerals lost while the cow sweats.


• Always make sure a clean, abundant water source is available, especially after milking.

• Use of feed additives, such as buffers and yeast cultures, can help maintain milk production in warmer weather. Buffers help maintain rumen pH which is particularly important when intake is volatile, and buffers often contain high amounts of sodium. Yeast cultures enhance fiber digestion, thereby lowering heat produced internally.

Beyond changing rations, paying attention to environmental conditions can help reduce the impact heat stress has on the herd and your bottom line. Schimek suggests the following environmental changes:

• Place sprinklers in the holding area and bunk lines.

• Clean fans and do regular maintenance to ensure they are running efficiently.

• Make sure shade is available, especially in outside situations.


Control flies so they don’t prohibit cows from eating.

Additionally Schimek recommends changing feed delivery times and feeding more frequently when feasible. “Cows tend to eat more during the cooler times of the day — before sunrise and later in the evening,” he says. “By feeding twice daily, the feed will be cooler, fresher and more palatable to the cow since it hasn’t been heated throughout the day.”

Of course, when making any changes to the herd’s diet, it’s important to talk with your nutritionist or feed consultant. This ensures balanced rations are fed to your herd and productivity is not lost. PD

—Excerpts from Hubbard Feeds press release

Lori Stevermer
Product Manager
Hubbard Feeds Inc.