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Avoiding Heat Stress in Livestock

Author: Allison Kosto, MSU Broadwater County Extension Agent MSU Broadwater County Extension Agent

Allison Kosto

MSU Broadwater County Extension Agent

We just survived a sweltering weekend with record high temperatures. While it was great weather for our farmers putting up hay, it was rough on humans as well as livestock. We often hear precautions of heat stress in humans, but it is also something to watch for in livestock.

Heat stress can happen easily during hot weather, especially when there is little to no cloud cover, lack of air movement, high humidity and high overnight lows. However, it can also happen as a result of overexertion of physical activities, even when temperatures are moderate. While not as common in Montana, in other parts of the country, the heat index is used to monitor potential for heat stress. For example, a heat index over 100 is stressful for animals, but if they have shade or there is a slight breeze (at least 10 mph) then they will be fine. However, as the heat index reaches 115, animals should not be handled or transported, which further increases their stress and heat load.

Signs of heat stress include seeking shade or crowding in the shade, panting, slobbering, excessive salivation, and trembling. If you see any of these signs, immediately try to reduce or minimize stress to the animal. Animal health is directly related to how well an animal can tolerate heat or any type of stress. Animals with current or past health problems are more likely to be adversely affected by stress.

Heat stress can result in reduced feed intake, weight gain, milk production and reproductive efficiency. It also increases their susceptibility to disease and decreases the animal’s natural ability to fight off pests.

The ability of livestock to handle heat can vary. For example, light-hided animals handle stress better than dark-hided animals. Older mature animals handle heat better than younger animals. Even certain breeds within species are known to handle heat better. Bos indicus cattle, such as Brahman cattle, handle heat better than European breeds (also called Bos taurus breeds). Wool of sheep can act as an insulating barrier. Research shows that sheep with 1 inch of fleece tolerate heat better than sheep that were freshly sheared. Pigs are unique because they don’t have sweat glands, so are especially susceptible to heat stress.

The best strategy to prevent or reduce heat stress is to be proactive before a heat wave by making sure the infrastructure is in place to handle the heat. Make sure the animals have plenty of shade, either from trees, buildings, or sunshades. If appropriate, such as in a chicken coop or barn, provide ventilation. Ideally, more than just opening a window, although that’s better than nothing. If you can, provide a fan to help keep air moving.

Provide clean, cool drinking water at all times. Water consumption will increase as the heat increases. Not only does water prevent dehydration, but it also allows heat to dissipate through sweat and urine. At 90 degrees F, animals will drink nearly twice as much water as at 70 degrees F. Having cool water to drink is important because it helps animals regulate their core temperature. If the water is hot, then it doesn’t help in the same way that cool water will.

Other strategies you can use include using a mister, wetting or using a sprinkler to help cool animals. These are great options for pigs who often need a little extra help on hot summer days.

For more information about livestock production, contact MSU Extension Office in Broadwater County at 406-266-9242 or allison.kosto@montana.edu or find us at 416 Broadway in Townsend.