How do ruminant animals turn forage into meat, milk, and wool?

Ruminants, such as cattle, sheep, and goats, do not have four separate stomachs; rather, they possess a single stomach divided into four specialized compartments: the rumen, reticulum, omasum, and abomasum.12

This system allows them to derive energy from cellulose, a fibrous plant material that most animals cannot digest. The process works as follows:12

• Fermentation: Ingested forage enters the rumen, which acts as a fermentation vat. Microorganisms break down cellulose into volatile fatty acids, which serve as the animal's primary energy source.32
• Rumination: To further break down tough fibers, the animal regurgitates the material as cud and chews it again, increasing the surface area for microbial action.13
• Digestion: The food moves through the reticulum and omasum, where water and nutrients are absorbed. Finally, it reaches the abomasum—the true stomach—where enzymes and acids digest proteins, including microbial protein, before absorption in the small intestine.23

This efficient conversion of fibrous plants into high-quality protein and energy supports the production of meat, milk, and wool.2