Being proactive is the best way to deal with heat stress in cattle.
"Once cattle are in a severe state of heat stress, you may be too late to help them," cautions Carl Dahlen, a North Dakota State University Extension Service beef cattle specialist. "Having a solid management plan in place to address heat stress could pay big dividends in the form of maintained animal performance during periods of heat and in avoiding death losses in severe cases."
Heat stress occurs when cattle are not able to dissipate heat.
Mammals have involuntary methods of regulating their internal body temperature, including shivering and sweating, to maintain "homeostasis," or a constant, stable environment, according to Charlie Stoltenow, NDSU Extension veterinarian.
Signs that animals are trying to maintain homeostasis include an increasing respiration rate, increased heart rate and increased panting. While animals are using extra energy, their feed intake declines.
Dahlen and Stoltenow recommend producers take the following steps to protect cattle from heat stress:
* Identify animals that are most susceptible to heat stress. They include feedlot animals closest to the market endpoint, very young and very old animals, and those with dark hides.
* Develop an action plan to deal with heat stress.
* Know when to intervene. A combination of factors, including temperature and humidity, drives heat stress.
An action plan should include the following:
* Give each animal access to at least 2 inches of linear water trough space in a pen. This means that in a pen with 200 animals, you need to have 400 inches of linear water space. If your cattle have access to only small water troughs, add temporary space for additional water access during the summer.
* Evaluate your water supply lines and ensure you have sufficient water pressure and flow capacity to keep troughs full during times of peak water consumption.
* Move the animals' feeding time to late afternoon or evening. This will allow rumen fermentation to take place during the cooler night temperatures, and it will increase the cattle's lung capacity during the hotter daytime temperatures.
* If feeding once daily, consider moving feed delivery until the afternoon. If feeding multiple times daily, consider feeding a small meal in the morning and a larger portion of the diet later in the afternoon. Decrease the amount of feed offerings during and for several days after heat stress.
* Provide adequate air movement. Remove unessential wind barriers (portable wind panels, equipment, weeds and other objects) to promote better air movement.