Heat Stress – Dr. Reinhardt

(Chris) Chris Reinhardt, Extension Feedlot Specialist for K-State. We want to talk, it’s the middle of summer, coming on to the middle of summer, and heat stress in Kansas, particularly the middle third to the eastern half of┬áKansas, heat stress is always a concern for feedlot cattle and any confined cattle that we have. And the thing I like producers to remember is heat stress is really a multi-faceted problem. High temperatures high humidity, low wind, and low cloud cover. When we have a perfect storm so to speak, of high temps, high humidity, low wind and low cloud cover that’s when, particularly our black hide cattle are really going to suffer if they don’t have an opportunity to find shade. If the wind keeps up in typical fashion, cattle can have heat stress and yet not be critical. If we have cloud cover, that keeps the black hided cattle from really being pushed over the edge. But when we have a combination of those four elements, we’ve really got to watch out for the welfare of the cattle. Providing some sort of shade, number one is again, cattle in heat and humidity conditions will appear stressed and they will be stressed, but they won’t be critical if they can find shade. If we can provide shade, or if we can’t provide shade, we’ve got to really keep an eye on the cattle looking for the extremely stressed animals, particularly heavy cattle. Heavy cattle that have been on feed a long time, carrying a fair bit of finish and condition. Those cattle are going to be extremely susceptible to the extreme conditions. If cattle have access to water especially standing water, ponds, you’ll see them in the heat conditions, you’ll see them crawling into the water. That’s when we know cattle are near the breaking point. They’ve sort of essentially forgotten about performing, grazing, doing what comes natural, they’re just trying to alleviate the heat stress. If we’ve got cattle in confinement placing out extra water sources is absolutely critical when we get into really extreme heat events. A lot of times we’ll see the boss cattle hovering over the water supply and it’s not because they are drinking, they’re simply breathing the cooler air over top of that water supply. And what they’re doing is they’re preventing other animals from getting a drink when they need it. And so by placing out extra water, number one we’re providing additional water drinking capacity, but we’re also preventing those bully cattle, those boss cattle from preventing more timid cattle from getting the drink they need. All summer every producer who has cattle in confinement should be monitoring the weather every day. And most likely you are. But again, we want to monitor those four things, the high temperature, the high humidity, the lack of wind, and the lack of cloud cover and again the other thing we like to keep in mind, it’s not just the peak temperature, but if the temperature over night doesn’t drop below, let’s say 72-75 degrees, we know cattle are going to carry a heat load into the following morning and the following day. So, if we have a series of extremely hot, humid days, especially in the eastern half of Kansas, we’ve really got to watch out for the welfare of cattle. And so as we’re driving by pens, particularly between 10 a.m and 4 p.m. is when we’re going to see the peak heat stress on cattle, particularly when there is extreme heat events passing through our part of Kansas. As we are driving through the pens in the afternoon when we’re experiencing some extreme heat weather, what we’ve got to look out for is open mouth panting. Open mouth breathing is, I’ll say essentially an unnatural act. Those cattle are at or near the breaking point in terms of…again they’ve abandoned all normal comfort modes and they’re really ramping up the machinery to try to cool off. They’re trying to expel extra heat by panting. Number one, they’re trying to get rid of heat, but in that process they’re evaporating a tremendous amount of water as well. And so when cattle are open mouth panting and exhibiting sort of that post, that four post saw horse sort of configuration, trying to expand their chest capacity simply to turn over a huge air volume, we know cattle are at or near the breaking point and it’s time… it’s possibly time to have to intervene in terms of spraying down cattle and providing some immediate relief.

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