Why does weight loss occur?

Weight loss in mature horses can occur for a number of reasons. The fundamental reason for weight loss is simple – the horse is expending more calories (energy) than he is consuming. This can be because he is exercising more and his diet has not been adjusted. The temperature has decreased and the horse is using more energy to stay warm. If the horse is sick or injured he will use significantly more energy to heal and recover. Sickness of disease that results in a decreased appetite will decrease the calories being consumed. Adding fat to the diet will markedly increase the caloric density of his feed without increasing the bulk of his feed. Average sized horses (500kg) can be fed as much as 2 cups of oil per day. When adding fat to the diet it must be done gradually like any feeding change.