Managing heat conditions is important for Kansas cattle

Not only do hot summer days make people uncomfortable outdoors, it can also impact livestock.

Kansas State Research and Extension beef veterinarian A.J. Tarpoff said temperature, humidity, wind speed and solar radiation all affect cattle. Not only do producers need to watch daytime temperatures, Tarpoff said nighttime temperatures are just as important in preventing heat stress.

“They really need about six hours of nighttime cooling to dissipate the heat load they accumulated during the day,” Tarpoff said.

Two forecasting tools Tarpoff recommends are the U.S. Meat Animal Research Center’s heat stress monitor and the Kansas Mesonet.

To minimize the amount of heat stress on the cattle, Tarpoff advises producers to finish all processing or handling work with cattle before 10 a.m. on hot days, and potentially to push feeding times to later in the evening.

“When we feed cattle, they will actually increase their heat load just from digestion for the next 4 to 6 hours,” Tarpoff said.

He also recommends reducing the stocking load, which increases spacing and allows for better air circulation and easier access to water.

“During the summer months we want to increase wind speed as much as we can just to be able to dissipate some of that heat load,” he said.

Another strategy that Tarpoff recommends is providing cattle bedding and shade so that animals

have a cool place to lay.“Cattle have an immense shade seeking behavior,” he said. Tarpoff said water misters should only be used in the morning and evening for evaporative cooling of the pen surface.

“We don’t wet the cattle to cool them during the heat of the day,” he said. “That can be disastrous because we can actually increase the humidity at the pen level at that time of day.” When cattle do become stressed, ranchers must carefully watch for serious health conditions. Heat-stressed cattle will show signs of open-mouth panting with quick, shallow breathing but can still stand, while a heat-stroke cow will usually be down and not rise. A heat-stroke cow will
have shallow, rapid respirations and usually appears depressed or even comatose; much like a milk fever cow. The pupils of the eyes will be dilated. The animal will feel hot to the touch. She may or may not be sweating.

Heat-stroke animals tend to not drink water, while a heat-stressed animal will. Basically the difference between a heat-stressed cow and a heat-stroke cow is that the heat-stroke cow will have lost control of normal functions (cannot stand, won’t drink, be nonresponsive, or comatose). Unfortunately, milk-fever cows and coliform-mastitis cows show these signs as well, so you must check the quarters for watery secretions and take into account if she is just fresh and an older cow (suspicious for milk fever/low calcium). The older fresh cows sometimes get
“caught” in the sun and can’t get out of the area since they are too weak to get up from the milk fever. Treat the milk fever first. It is entirely possible that a cow that started with milk fever or coliform mastitis also develops heat stroke.

Heat-stroke and heat-stress animals are primarily treated by hosing down the animal with cold water continuously for twenty to thirty minutes, head to tail, with special attention paid to hosing the back of the head since this is where the cow’s temperature regulation center is. Heat-stressed cows will often stand still to be hosed down with no need of tying them to anything.

In the final analysis, environmental management is a very important skill for farmers and ranchers to hone. Although we cannot control the weather, we certainly can control the areas our cows inhabit to help prevent potential disasters in the heat of summer.