By our standards dogs are disgusting. Eating their own or other animal droppings is high on the disgust list, but is a natural activity in a scavenging species especially when there is nutritional value in the scavenged stool, which there is in herbivore droppings, from horses, rabbits and deer.
This doesn't explain the dog's predisposition to look upon the carnivorous cat's litter tray as a gourmet treat. Reasons for eating stools include residual puppy behaviour and boredom. A minority of pets have medical reasons for this behaviour including malabsorption conditions, intestinal parasites, diabetes and overactive adrenals (Cushing's syndrome) or thyroid (hyperthyroidism).
Visit us to ensure there are no medical reasons for the behaviour no medical reasons for the behaviour. Clear all droppings from your pup's environment. Alternatively, this may sound strange but, inject something unpleasant but safe, like Tabasco Sauce, into a piece of stool your pet is likely to eat. The experience of eating it will be unpleasant and unlikely to be repeated. This is called "aversion therapy".