August 2017
Feeding Facts

Battling Heat Stress

Global warming has been a hot topic now for several years. Some believe it will increase ambient temperatures and kill us all, while others argue that it is just part of nature’s cycle and nothing to worry about. Let’s look at a related topic that we can all agree on: August. There is probably little argument that August in Alabama will bring hot and humid weather. Hot, humid days followed by hot, humid nights give our livestock little or no time to cool off and heat stress becomes an issue plaguing Southern producers. In fact, research has shown heat stress costs the U.S. livestock industry at least 2.4 billion dollars each year. In most areas, livestock have heat stress on summer days, but are able to cool off at night. In the late summer in Alabama and most of the Southeast, our livestock do not get that cool period at night to really cool off. The temperature may go down some, but with our high humidity, if the nighttime temperatures stay above 85 degrees, they just can’t cool off and heat stress becomes a profit-stealing reality.

How does heat stress reduce livestock profits? In severe cases, the animal dies, but, hopefully, that is the exception rather than the rule. In mild and moderate cases that all producers in Alabama deal with, heat stress lowers feed intake (including grass or hay), lowers nutrients available for absorption and causes absorbed nutrients to be used less efficiently. The animal will normally eat less, because eating and digesting less creates less heat from the digestive process. When they eat less, they take in less energy and other nutrients needed to help them fight the heat and cool themselves. Now they are too hot and deficient in the nutrients needed to combat the problem. The body will take care of itself as best it can. Those needed nutrients will be taken from other areas within the body and production is severely reduced in all species of livestock.

What can we, as producers, do to combat heat stress? Aside from providing plenty of clean water, you can do three main things. First, we look at genetic selection. All producers can look at a selection of adapted animals. Most all livestock will redirect blood flow toward the skin in an effort to cool off and thicker-hided animals with more skin cool more efficiently. It is a slow fix, but one that can pay dividends for generations. Second, we can look at the design of our facilities. They can incorporate features most often used with poultry, pork and dairy cattle. Sprinklers and fans can do wonders for cooling livestock. Finally, we have feeding options. To a degree, there are ways to feed and products that will help alleviate the issue. Changing feeds is the quickest and easiest way to combat the problem and the only feasible way to address this issue.

What can we feed to help? We have to look at reduced intake and combat that issue first. Many of the livestock species we have will reduce intake by 25 percent when temperatures approach 90 and even more above that. Because they are eating less, we need to offer a more concentrated source. Other than water, energy is the most important nutrient at this time. Protein and fiber digestion produces more heat than starch and fat digestion. We would like to offer a palatable feed to entice the animals to consume it and that is high (but not too high) in fat and starches, and lower in proteins and fibers.

When we think about grazing animals and August, we need to realize our forages are generally mature and at a low point as far as quality goes. They tend to be higher in fiber and lower in everything else. They compound the problem of heat stress because fiber digestion increases the heat produced inside the animal. Twenty-five to 40 percent of all the energy in forage can go to heat production as forage quality decreases, and that typically happens when we have our hottest temperatures.

Your local Quality Co-op offers several products to help animals continue to be productive by helping to relieve heat stress. Formax Beef feeds offer several good options, including a Finisher with enough fat to be a good choice. Both the Grower and Developer will also work well. Another really good choice would be STIMU-LYX Hi-Mag Fescue Relief with Tasco. Yes, I know we will not likely be grazing fescue in August but it does have lower protein than some other feeds, and Tasco is an excellent choice, given it will decrease an animal’s body temperature. It also has a good level of potassium that becomes more important as an animal loses electrolytes through their natural cooling processes. The production of saliva that comes from licking those blocks helps with the animal’s pH maintenance, a problem during heat stress.

On a more fun-side note, do you know which farm animals can cool themselves by sweating? Chickens and other poultry do not; they pant. Pigs actually can sweat, but their sweating is not triggered by temperature; they have to pant to cool themselves. Horses sweat profusely. Cattle, especially Brahman-influenced cattle, sweat. Sheep sweat less than cattle, but more than goats. Goats sweat, but mainly on the head and neck, which may help keep their brains a bit cooler.



Jimmy Parker is AFC’s animal nutritionist.