Question

My horse has started eating another horse’s manure. Last week, I took him off his omeprazole granules as he is spelling (resting) for two weeks, and I thought I would see if he could cope without the medication. Do you think it's related? He’s been on the same balanced diet for 18 months, and other than this, he’s doing well.

Answer

Coprophagy, or eating manure, is not uncommon in young horses. Foals are thought to eat manure to populate their hindgut with beneficial bacteria. Mature horses that ingest manure are less ordinary, and the behavior is often associated with a lack of long-stem fiber in the diet.

Horses that consume a low-fiber, high-grain diet or a protein-deficient diet may engage in coprophagy.  When grass begins to grow in the spring, it provides abundant forage that is high in moisture and carbohydrates but low in fiber. An easy dietary adjustment is to increase the amount of forage by increasing hay intake to at least 1.25% of body weight per day.

A possible link could be made between the removal of the ulcer treatment and the increased probability of gastric discomfort. It may be a good idea to add some alfalfa (lucerne) hay to his ration.

Alfalfa provides greater buffering capacity compared to grass forages for two reasons: (1) alfalfa contains higher levels of protein and calcium, both of which buffer gastric acid; and (2) alfalfa contains certain indigestible compounds such as lignin that gives it a greater buffering capacity than grasses.