Cattle, sheep and goats, as well as other ruminant animals, are useful as subjects in certain special research projects. Polygastric animals utilize large populations of microorganisms, which break down cellulose to form short-chain, volatile, fatty acids commonly called VFA. These volatile fatty acids provide the ruminant with 60-80% of its energy needs.

Break down of the cellulose walls of plants by bacteria makes the other cellular food constituents such as fat, starch and protein available for further digestion as they move through the gastrointestinal tract. Ruminants are not popular laboratory research animals because they are expensive to maintain.

The size of the animals increases their cost of maintenance due to:

  • Space allocation per animal
  • Feeding cost per animal
  • Value of each animal
  • Labor and maintenance time

However, these domesticated animals are easy to work with because of their gentle dispositions and consistency of their biological performance. They are also more conducive to long-term research studies because they have a much longer life span than rats and mice.