Targeting Heat Stress

Heat stress contributes to the death of several thousand feedlot cattle annually nationwide and hurts the performance of many more.

Terry Mader, animal scientist at University of Nebraska's (NU) Haskell Agricultural Lab near Concord, is coordinating a three-year, multi-state research project to better understand, predict and prevent heat stress in feedlot cattle. One goal is to develop management systems that warn feedlot operators of impending heat stress and to offer specific recommendations that minimize or prevent cattle deaths and significant performance declines.

The team of scientists from NU, Purdue University, the University of Missouri and USDA's Meat Animal Research Center will apply its findings in selected commercial feedlots in 2001. Funding for this research is through a USDA National Research Initiative grant.

Meanwhile, here are four clues provided by NU faculty for monitoring a potential heat stress problem in cattle.

  • Hot weather following precipitation can be stressful for feedyard cattle. It is the combined temperature and humidity that determines the severity of heat stress. Days with temperatures in the high 80s or above following a precipitation event can be extremely stressful, especially if the wind speed is below 5 mph for extended periods.

  • Monitor the upper critical temperature-humidity limits of cattle. Consider this limit has been reached when the Temperature-Humidity Index (THI) reaches 80 (i.e., 86°F at 60% relative humidity.

  • Watch out for evening weather forecasts that call for overnight temperatures to remain above 70°F. Feedlot losses have been commonly reported when consecutive days with THI values above 80 have been tied together with nights in which the temperature stayed above 70°F.

  • Be watchful of cattle moving around the pen looking for an area that is more comfortable. Heat-stressed cattle will start to slobber and respiratory rate will increase above 100 breaths/minute. They elevate their heads to breathe and position their bodies to minimize exposure to the sun.
    University of Nebraska

CGF Saves $$$

Further proof that corn gluten feed (CGF) saves cattle feeders money is in a recent bulletin — “Corn Gluten Feed” — released by Kansas State University.

K-State animal scientist Dale Blasi says the increase of corn production in Kansas has farmers and cattle feeders looking for by-products that increase the crop's value and lowers feed costs. CGF is produced from the wet corn milling process.

Blasi says CGF offers significant energy, crude protein, digestible fiber and minerals. It can be fed to cattle on grass or in finishing diets.

Use of CGF can help cattle producers reduce costs dramatically if it's readily accessible and priced competitively.

For more information on CGF go to

Compiled by Clint Peck. Contributions welcome: Phone or fax to 406/896-9068 or e-mail at