Date: Around 1993
How long it takes for the digestive process to work in a
ruminant? With the various chambers and would digestion take longer than in
A friend in animal nutrition is looking up an exact figure, but
as he does, here are a few guidelines: Time of digestion largely depends on
the type of food an animal ingests:
CARNIVORES: short, uncomplicated digestive systems. They eat very high on
the food chain (other animals), which provide food stuff which is relatively
easy to digest. Hence, rapid digestion.
OMNIVORES: medium length, medium complex digestive systems. We eat at all
levels of the food chain, and so need a balanced system. Medium time of
digestion (roughly 2-10 hours per meal, depending on proportions of
carbohydrates, fats, proteins).
HERBIVORES: (ruminants): long, complex digestive systems. They eat very
low on the food chain (plants), and require more elaborate digestive
capabilities (even help from microorganisms). Hence, longer digestion.
Here is what Dr. Ingalls and his colleagues discovered from deer: Time for
passage of food from rumen:
alfalfa dry matter: 15 hr
trefoil: 15 hr
timothy: 20 hr
canary grass: 23 hr
(Ingalls JR, Thomas JW, Tesar MG, Carpenter DL. Relations between ad libitum
intake of several forage species and gut fill. Journal of Animal Science.
25(2):283-289. That is a long time just to get past the first stage of
digestion! Another researcher, Dr. Church, discovered that many factors
controlled the passage rate of food in ruminants: physical nature of the
food, particle size, digestibility, specific gravity, and amount eaten.
Smaller particles passed through more quickly. When the animal ate more food
at one time, this also increased passage time. Generally, passage rate
through the entire digestive system took twenty-four to forty-eight hours.
Also, remember that ruminants include a wide variety of animals, which differ
widely in many ways. They range from the diminutive mouse deer (rabbit-sized)
to the middle-sized deer to the large-- sized cattle and giraffes. Their
digestive capabilities and diets are as varied, so digestive times vary, too.
A good book discussing ruminant digestion and nutrition: Wildlife Ecology, by
Aaron N. Moen, Publisher: W. H. Freeman & Co., 1973
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Update: June 2012