In most cases, coprophagy is not an illness, per se, but a habitual behavior. For this reason, treatment usually focuses on altering the environment instead of the animal itself. In older horses, such behavior may indicate some type of deficiency, one that has to be corrected through changes to diet or supplementation. Once the minerals or vitamins that they are lacking are restored, the coprophagy is likely to cease. However, in some cases, if the coprophagy has continued for a long period of time, it becomes a habit and may not stop if only the deficiency is corrected.
If your horse persists with the dirt eating or manure eating past the time when it is acceptable, something will need to be done to change the situation before it causes problems with the health of the horse. Removing the horse from the area where it has access to manure, or where the dirt may be tainted by manure may work in cases that are more difficult to resolve. Your equine veterinarian will have more information to share with you on the topic, and will be able to determine which behavioral modification methods will work best for you and your individual horse.
Keeping stalls and small paddocks free of excessive manure accumulation will help reduce the temptation of coprophagy in a horse. Also providing a complete horse feed that has been formulated to ensure proper mineral balance along with plenty of roughage will help keep your horse on an excellent plane of nutrition. Providing proper mental stimulation by interacting with your horse on a regular basis and ensuring he has enough space to exercise himself and graze will help decrease the chances of developing a stereotypic behavior, such as what coprophagy can become in the older horse.
A type of animal feed that is high in fiber; may include hay or pasture crops
The eating of grasses and plants that are low to the ground
The name for the species of horses, donkeys, mules
The feces of an animal; excrement or manure