The stresses of summer heat can be challenging to both man and beast. When temperatures soar, we begin to implement strategies to protect our own health; likewise, as good stewards, we also need to think about the effects of heat stress on our livestock. Cattle and most other domestic species cope well until environmental temperatures exceed about 68 degrees Fahrenheit. Beyond this comfort limit, they begin seeking shade and water and can be observed panting in an effort to shed excess body heat. What may not be as obvious are the problems related to lost production due to decreased forage intake, depressed milk production, and lower reproductive rates. Some simple common sense strategies can help your livestock deal with the effects of summer heat.
Cattle have a limited ability to sweat and rely mainly on panting to increase evaporative heat loss through their lungs and nasal passages. This, along with dilation of blood vessels near the surface of the skin to increase radiant and convective heat loss, results in a significant increase in daily water needs. Make sure ample fresh water is always available and easily accessible by the herd. Stagnant ponds are not recommended, as cattle will wade, defecate, and urinate in the same water they drink. Such ponds soon become reservoirs for bacteria, increasing the occurrence of mastitis and other infections. If no other alternative exists, use temporary fencing or physical barriers to limit access to ponds so that drinking is the only option.
Shade in the form of trees or manufactured shelter can reduce solar radiation gain by cattle as well as the ground they stand on. Cattle tend to congregate in the most comfortable spot, and this can lead to the accumulation of mud, increasing the potential for foot rot and other hoof problems. Use portable panels or electric fencing to exclude cattle from an area until it has time to recover.
If your are providing supplemental feed, offer the ration in late afternoon so the heat of digestion occurs overnight when temperatures are lower. Avoid working or moving cattle on the hottest days when possible. When unavoidable, plan the activity in the early morning hours, move animals slowly and calmly, and avoid overcrowding. Decrease load density when transporting cattle, and minimize the time the animals must spend in the trailer.
Fescue endophyte tends to compound problems associated with heat stress by causing constriction of blood vessels near the skin surface. Grazing summer annuals or other grass species during the hottest months can eliminate this issue. Other solutions include feed additives designed to bind toxic alkaloids and/or dilate blood vessels to increase blood flow under the skin.
Flies cause cattle to generate more heat as the animals crowd together and try to dislodge the insects. Insecticide ear tags, pour-ons, sprays, and feed-through insect growth regulators (IGR) are proven control methods. The most convenient approach is a free-choice vitamin/mineral supplement with IGR.
Finally, even though cattle do not sweat as much as humans, heat stress increases the need for electrolytes to maintain sodium and potassium balance. Free-choice vitamin/mineral supplements designed specifically for supplementing fescue can address these needs, as well as deliver fly control and an ionophore to improve feed efficiency.
Healthy, comfortable animals tend to be productive, profitable animals. Take steps now to ensure your herd is ready to deal with summer’s heat.