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McClain County

Reducing the Incidence of Heat Stress in Cattle

Understanding and avoiding heat stress in cattle can be a valuable management tool in Oklahoma, where most areas of the state experience 70 or more days each year with temperatures that exceed 90 degrees Fahrenheit.

Understanding and avoiding heat stress in cattle can be a valuable management tool in Oklahoma, where most areas of the state experience 70 or more days each year with temperatures that exceed 90 degrees Fahrenheit.  Cattle have an upper critical temperature that is approximately 20 degrees Fahrenheit cooler than humans.  When we’re uncomfortable at 80 degrees and feel hot at 90 degrees, cattle may well be in the danger zone for extreme heat stress.

     The potentially bad news does not end there. Humidity is an additional stress that intensifies ambient temperature problems by making body heat dissipation more difficult. In other words, it can be tough to cool off in Oklahoma during the summer, for people and cattle. 

     High humidity contributes to the likelihood of heat stroke or prostration because water evaporation from the oral and nasal cavities is decreased, in spite of rapid panting, a heat regulatory device in cattle.  Panting often occurs at rectal temperatures at or above 104 degrees Fahrenheit, but may begin at even lower body temperatures.

     Signs of overheating in cattle may develop suddenly and depend on the environmental conditions and health of the animal. Some overheated cattle manifest restlessness, excitement and muscle spasms. Others may be dull and depressed. A protruding tongue may be covered with saliva, and frothy mucus may be discharged at the nostrils.

     Fortunately, overheating in cattle can be prevented under most management conditions. Access to shade and air circulation should be provided if possible.  Allowing cattle access to fresh water and mineral supplements is a must during hot summertime weather. Cool, fresh water is especially vital for animals that are in close, confined areas for any length of time. During hot weather, cattle will drink more than 1 percent of their body weight per hour.  Producers need to be certain that water supply lines are capable of keeping up with demand when working cattle during hot weather.  

    It is a good idea for producers to work cattle before 8 a.m. during hot weather, and all cattle work should be completed by 10 a.m.  While it may seem to make sense to work cattle after sundown, they may need at least six hours of night cooling before enough heat has dissipated to enable them to cool down from an extremely hot day.  Cattle that must be handled during hot weather should spend less than 30 minutes in the working facility, according to OSU recommendations. 

    Excitable cattle will be even more prone to heat stress if handled at high environmental temperatures.  Dry lot pens and corrals loaded with cattle will have little if any air circulation. Cattle will gain heat constantly when in these areas. By limiting the cattle’s time in a working facility, the producer can help limit the animal’s heat gain and therefore the heat stress. If animals are going to have limited access to water under stressful conditions such as shipping by truck or trailer, they should be allowed water prior to further stressful situations. 

     It is fortunate that most cattle handling for health and production purposes in Oklahoma occurs in the relatively cooler weather of spring and fall, resulting in only an occasional need for cattle handling in the heat of summer.

The Oklahoma State University Cooperative Extension Service offers its programs to all eligible persons regardless of age, race, color, religion, sex, sexual orientation, genetic information, gender identity, national origin, disability, marital or veteran status, or any other legally protected status. OCES provides equal opportunities in programs and employment.

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