Why are poultry and swine collectively called non-ruminant animals?

Poultry and swine are collectively referred to as non-ruminant animals because they lack a rumen, which is a specialized compartment of the digestive system found in ruminant animals such as cattle, sheep, and goats.

The rumen is a large, sac-like organ that houses a complex microbial ecosystem. Microorganisms within the rumen break down and ferment plant materials into volatile fatty acids, which can then be absorbed and utilized by the animal as energy and nutrients.

Poultry, which typically includes chickens, turkeys, ducks, and geese, have a relatively simple digestive system that lacks a rumen. Their diet consists mainly of grains and seeds, which are mechanically broken down in the gizzard, a specialized muscular stomach.

Swine, which includes pigs and hogs, also lack a rumen. Their digestive system is relatively short compared to ruminant animals, and it functions primarily to break down and absorb digestible nutrients from grains, legumes, and other feedstuffs.

The absence of a rumen in poultry and swine means that they cannot efficiently digest and utilize certain types of complex plant materials, such as cellulose, which is the main component of plant cell walls. As a result, their diets must be supplemented with nutrients that they cannot obtain from plant sources alone.