Ruminant. Animal Nutrition. Herbivores. How do herbivores eating grass/ plant material digest this food? Grass is low in energy – how does this affect their eating habits? Cellulose cell wall – need access to the energy store. Ruminants.
“Ruminants are earth’s dominant herbivores, due in part to the evolution within this group of a mechanism utilizing microorganisms to digest plant components not susceptible to attack by ruminant enzymes.” (Hungate 1975)
deer, moose, antelope, giraffe, caribou, cow, sheep, goat
Food passes the reticulum and enters the rumen
Fermentation occurs in the rumen
Food passes back into the reticulum
Sent up the oesophagus to be re-chewed
Passes back down oesophagus into the reticulum
Moves into the omasum
Passes into the abomasum
Mouth, esophagus, liver, pancreas, gall bladder, small intestine, and large intestine have functions similar to monogastrics.
Lined with millions of papillae (short projections on wall of rumen) needed for absorption.
The fermentation reaction:
cellulose --> acetate, propionate, butyrate, CO2, CH4, H2O
three main products that benefit the animal
i) Volatile fatty acids: acetate, propionate, butyrate
these pass through the rumen wall and are absorbed
propionate – used for carbohydrate biosynthesis
acetate, butyrate – used for energy
ii) microbial cells – contributes protein to ruminant’s diet – probably the main source of protein
many rumen bacteria can use urea as a sole N source; often part of cattle feed to promote protein synthesis (cheap meat)
iii) Heat – important to the ruminant’s thermoregulation
The rumen contains bacteria and protozoa