Sources: Tom Priddy and Matthew Dixon, UK Agricultural Meteorologists

Summer is here. We’ve already experienced a little bit of heat and humidity, just a taste of what’s to come. Humans aren't the only ones who suffer when the temperatures rise. Farm animals feel it, too. You can recognize when livestock may be in danger from the heat and what you can do to increase their comfort.

Livestock become uncomfortable when the heat index reaches about 90 degrees. The heat index is a combination of air temperature and humidity and is often used to describe how it feels outside. Periods of heat stress call for livestock producers to be vigilant in making sure their animals are adequately prepared.

The University of Kentucky Agricultural Weather Center regularly monitors heat indices across the state and provides an index of its own – the Livestock Heat Stress Index – to help producers know when heat stress could create a problem for their animals. The county-by-county index indicates three levels of heat stress: no stress, danger stress and emergency stress.

Some of the early warning signs of heat stress in livestock are slobbering, high respiratory rate (panting), open mouth breathing, lack of coordination, trembling, increased water intake with reduced feed intake, and increased respiration rate (90 breaths per minute).

One of the most important things you can do is provide cool, clean drinking water. Providing an adequate source of drinking water helps keep animals’ internal body temperatures within normal limits. You should shade above-ground water sources so they do not act as solar water heaters and make the water too hot to drink.

This can be done by increasing the circulation of the water in tanks or preventing direct sunlight from hitting the water in tanks as needed. Preventing cattle from standing in ponds and creeks can help not only save water but increase the quality of water that they have to drink.

It is also important for animals to have shade and for buildings to be as open as much as possible for adequate ventilation.

Types of shade that we can take advantage of are:

Natural shade- the least expensive type of shade, a great example of this would be existing trees. Though they are good at blocking incoming solar radiation and the leaves help cool surrounding air, they are not always where you need them. Congregating cattle can cause areas of intense erosion and reduce effective utilization of pasture. In order to prevent this problem rotate cattle from tree-lined areas with natural shade and provide other shading methods.

Permanent shade- provided by barns or sheds. In a grazing system, permanent shade in pastures is costly and least efficient.

Portable shade- provides shade to your animals and the ability to utilize pasture. They are easily moved and relocated within your pasture, allowing you to move the systems were they are needed and can be most effective. These structures can be built in many different ways. One way is to build them from pipe and weld it to frame that will allow them to be moved easily from pasture to pasture. Shade cloths, which blocks 80% of the sun, can be used to cover these structures (See picture) to help cut down on weight. UK publication AEN-99 “Shade Options for Grazing Cattle” has more information on the importance of providing shade to livestock.

It is best to avoid working your animals during periods of heat stress. If you must work animals try to do it early in the morning or late in the evening when the heat index is going to be less stressful on you and the animals. Work at a slower pace and try not to crowd animals as much in pens or barns, make sure barns or holding facilities have proper ventilation. These are just a few ways to help lower stress levels on animals.

You should also avoid transporting livestock during times of high heat stress. When you must transport livestock, haul fewer animals per load. Plan trips so you can load animals immediately before leaving and quickly unload upon arrival to help minimize the risk.

The University of Kentucky Agricultural Weather Center is a great resource to help producers keep up-to-date with the livestock heat stress index, you can access the Agricultural Weather Center’s website at You can also contact the Pulaski County Extension office to get more information at 606-679-6361

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