Do you know your horse’s normal body temperature? It’s an important factor when trying to determine if your horse has a fever. If the ambient temperature is 100 F and your horse has a temperature of 101 F, it could be nothing. But if your horse’s baseline temperature is 99.5 F, a reading of 102 F could mean he has an illness or infection. Combine this with changes in behavior, appetite, or energy, and you could have a serious problem. Understand the causes of fever to be able to take quick action before a situation becomes critical.