In spite of improved drought conditions this year, Southwest cattle producers should keep a careful eye on the thermometer as dry, hot days can cause serious health problems that could result in reduced production and even animal death.

“In South Texas we saw a number of 100 degree days as early as April this year, and June temps climbed even higher than that. Combined with high humidity and a lack of wind, heat stress has already been a problem for some ranchers,” reports Dr. Joe Paschal, Texas AgriLife Extension Livestock Specialist in Corpus Christi.

Paschal, who runs cattle at his own South Texas ranch, says heat can be deadly for livestock, especially dark-hided stock like Angus.

“The darker the animal the more heat they absorb, so breed becomes a factor when considering heat stress in your herd. Also, cattle that aren’t from the region are not acclimated to extreme heat, and calves are especially troubled by excessive heat. Heat stress in livestock is a serious condition,” Paschal warns.

The first signs of heat stress are cattle laying down in the shade.

“As they become more stressed, they generally will seek out ponds and tanks they can wade into. In more advanced stages you can see them drooling from the mouth and nostrils and at this point you know you have a serious problem,” Paschal said.

The best protection you can offer heat stressed livestock is to make certain they have plenty of cool water to drink. While cattle may use stock ponds for wading, a source of clean water is a better option for drinking.

“I prefer a deep concrete water tank that has fresh, cool ground water pumped in regularly. The coolness of the water will help cattle shed the body heat and is a much preferred drinking source than a pond that is drying up and overused,” he added.

Weight loss

Depending on the degree of heat stress in cattle, it will result in reduced production and weight loss in cattle. Even with green forage available, cattle will tend to eat only in the cool hours of the morning before seeking shade and water.

“They eat less, burn more energy, and can reach a point of dehydration quickly under a hot sun. I find on a hot day that a rectal thermometer will show cows with body temps as high as 104 degrees. In dairy cattle and beef cattle that will slow down milk production and can ruin your chances of breeding animals. When semen is injected at 96 degrees into an animal with much higher body temps, the chances of embryo development is quickly reduced and even if it takes, there’s a chance it may not reach term,” Paschal said.

While dealing with the summer heat is a challenge every year for ranchers, planning for it can help once the heat sets in. Producers should be aware that transporting cattle becomes difficult in high heat conditions. Eliminating unnecessary stops along the route is a good idea and spraying down cows with water may be required to transport them safely.

“Some producers hook up a sprinkler or misting system that provides needed relief on really hot days. That and plenty of shade and cool drinking water can prevent animal death under the worst of conditions. I would not go more than a day or two without checking water sources and I would advise monitoring the herd regularly to determine the level of stress they may be suffering,” he added.

Severe heat stress will deprive cattle of oxygen and can result in heart failure.  While heat related losses can affect any class of cattle, in general, cattle in confinement are at greater risk. Air movement is typically greater in a pasture, and in some cases pastures offer greater opportunities for cattle to seek shade or ponds to cool off. Also, cattle fed on concrete or on a dark soil surface will have a greater exposure to radiant heat compared to cattle on grass.

Controlling flies will also help keep cattle from bunching in a group. That will allow more air flow to each animal. Feed 70 percent or more of the daily ration in the late afternoon or evening. By delaying feeding, peak rumen heat production will occur during the cooler part of the day.

Waterers need to be kept clean to encourage cattle to consume adequate water. The water supply should be able to deliver 1.1 percent of body weight of the cattle per hour. A 1,000 pound animal needs about 1.5 gallons of water per hour. You should check the water temperature in the water troughs at least once daily. Water temperature increases from 70 degrees to 95 degrees can increase total water requirements by about 2.5 times. And avoid working cattle during times of extreme heat. If you have to work cattle, do that early in the morning.