Goats cope with heat stress in a variety of ways. They may lie on their sides more than usual on a hot day or hang out under a tree all day and pant. Lying flat out, they also expose more body surface area, especially the short-haired parts of the body. When it gets hotter, involuntary functions kick into high gear.
The environmental comfort zone for goats is between 0-30C. Above 30C goats may begin to experience mild heat stress, especially when humidity cranks up the heat index. As heat and humidity climb, goats can have serious problems with thermal stress.
High temperatures affect body function in many ways. The hypothalamus, lying at the base of the brain, is in charge of balancing the body’s heat loss and gain by regulating respiration, skin temperature, sweating and muscle tone. Goats get eight times more relief from the heat by panting than by sweating, so rapid breathing is their primary form of cooling themselves. Panting and collapse are the most obvious signs of heat stress, and the rectal temperature will exceed 40C.
When the weather warms up, animals eat less in an involuntary effort to reduce body heat, feed and water consumption go down. Animals may reduce water intake however they need water to help keep them cooler. Weather and other factors can combine to get any goat, but some are more susceptible to overheating. Overweight goats cannot exchange heat efficiently. Aged goats just don’t function as well as they used to, and the very young have yet to reach optimum function. Animals in poor health (illness or parasites) may not be able to cope with this added burden. Selenium deficiency may exacerbate heat stress due to marginal muscle tone. Unventilated confinement, such as being locked in a poorly ventilated barn, crate or vehicle, can be a serious threat to an animal’s life in a very short time. Any forced exertion should be avoided. Don’t pick a hot, humid day to trim hooves or give the goats any other hassles.
A veterinarian should be consulted as soon as you see signs of heat stress. The animal may experience pain and swelling, and your vet may prescribe drugs to treat these symptoms. There may be a variety of moderate to severe blood abnormalities, impaired kidney function and metabolic acidosis. Electrolyte imbalances are common in heat stress, and IV liquids may need to be administered to combat acidosis.
Act promptly when you find a goat you expect is suffering from heat stroke. If the goat can walk, isolate it in the shade and take its temperature. If the temperature is over 40.5C, set a fan for direct ventilation, spray the coat with water, and wet the head, legs and stomach with water. (Cold water may be too great a temperature shock to the vascular system – any water will do). If the symptoms diminish in 15-20 minutes, the goat may continue recovery on its own. Make sure the temperature is reduced to 39.8C, and watch the goat closely for a few hours to see that it acts normally. Continue to monitor its behaviour, temperature, pulse and respiration after the animal has been stabilised. If the goat is prostrate and unable to walk, do not move it. Take its temperature. Erect shade if the animal is in direct sunlight and begin cooling with water. You will need the vet, tissue destruction begins prior to death, so prompt medical attention is imperative. When cooling therapy reduces the goat’s rectal temperature to 39.8C, cooling measures can be discontinued.
Remember, prevention is better than cure. Give free access to clean, cool water and freshen it frequently. In hot weather, move the water source into the barn if your goats normally have to travel to reach it. Ensure your goat/s have access to good shade and barns or living areas are well ventilated. Provide adequate barn and feeder space to reduce competition for resources. Ensure your goat/s do not undertake any activities that cause exertion or induce stress.