Sheep and goats are considered small ruminants. They digest food just like cows and other large ruminants. Goats, like all ruminants, have a four compartment stomach consisting of the rumen, reticulum, omasum, and abomasum.

The reticulum and rumen form a large fermentation vat that contains microorganisms, mainly bacteria, that breakdown and digest feedstuffs, including the fibrous component of grass, forbs, and browse that cannot be digested by monogastric animals. Some of the breakdown products produced through digestion of feed by bacteria are absorbed by the animal through the rumen wall and can supply a large part of the energy needs. The rest of the byproducts of digestion, undigested feed and ruminal microorganisms flow out of the reticulo-rumen into the omasum where large feed particles are trapped for further digestion and water is reabsorbed. Material then flows into the abomasum where acidic digestion takes place and then to the small intestine for further enzymatic digestion and nutrient absorption.

The greatest asset goats have is the ability and tendency to utilize woody plants and weeds, not typically consumed by other species of animals like cattle and sheep, converting these plants into a saleable product. These plant species can be inexpensive sources of nutrients and make for a very profitable goat enterprise. Goats typically consume a number of different plant species in any one day and can utilize some poisonous plants because they do not consume levels high enough to be toxic. Similarly, goats are believed to have a relatively high ability to detoxify absorbed anti-nutritional factors. Goats are more resistant to bloating than other ruminants and after a brief adaptation may graze alfalfa without bloating.

Goats are unique in the fact that they require large amounts of copper, which is typically a trace mineral. Goats need about the same amount of copper as a cow, even though they are significantly smaller.

Sheep however are sensitive to copper and can easily consume toxic amounts. Care should be taken when supplementing copper in small ruminant diets.