Ruminant
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A ruminant is any hooved animal that digests its food in two steps, first by eating the raw material and regurgitating a semi-digested form known as cud, then eating the cud, a process called ruminating. Ruminants include cattle, goats, sheep, camels, llamas, giraffes, bison, buffalo, deer, wildebeest, and antelope. The suborder Ruminantia includes all those except the camels and llamas, which are Tylopoda. Ruminants also share another anatomical feature in that they all have an even number of toes.
Ruminants have a stomach with four chambers, which are the rumen, reticulum, omasum, and abomasum. In the first two chambers, the rumen and the reticulum, the food is mixed with saliva and separates into layers of solid and liquid material. Solids clump together to form the cud (or bolus). The cud is then regurgitated, chewed slowly to completely mix it with saliva, which further breaks down fibres. Fibre, especially cellulose, is broken down into glucose in these chambers by symbiotic bacteria and protozoa. The broken-down fibre, which is now in the liquid part of the contents, then passes through the rumen into the next stomach chamber, the omasum, where water is removed. After this the digesting food is moved to the last chamber, the abomasum. The food in the abomasum is digested much like it would be in the human stomach. It is finally sent to the small intestine, where the absorption of the nutrients occurs.
Almost all the glucose produced by the breaking down of cellulose is used by the symbiotic bacteria. Ruminants get their energy from the volatile fatty acids produced by these bacteria: acetic acid, propionic acid and butyric acid.
Trivia
- One of the requirements of kashrut for a land animal is that the animal chews its cud.
Other uses
The verb "to ruminate" has been extended metaphorically to mean "to thoughtfully ponder" or "to meditate" on some topic. Similarly, ideas may be "chewed on" or "digested".
See also
External links
- [Digestive Physiology of Herbivores] - Colorado State University
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