Ruminants

RUMINANTS, Ruminantia, a group of even-toed mammals (Artiodactyla) belonging to the order of ungulates (Ungulata). The legs of even-toed ungulates bear an even number of toes due to the reduction of the first toe; the second and fifth toes are usually developed more weakly than the others, and in some ruminants, they are reduced entirely. The dentition in ruminants is incomplete due to the absence of incisors and upper canines in many of them. There are 20–28 molars of the chewing type, which, thanks to their folded surface, serve to grind plant food during the lateral movements of the lower jaw. They chew cud, hence the name Ruminants. They possess a complex quadruple or triple stomach. Food chewed in the mouth is swallowed into the first section of the stomach—the muscular rumen (rumen, or ingluvies); here it is ground by the walls of the rumen and passed further into the "reticulum" (reticulum, or ollula); after staying here for some time, the food is regurgitated back into the mouth and ground a second time by the molars ("cud"). After such mechanical processing, the food is swallowed again and passes along the esophageal groove directly into the third section of the stomach, which has a mucous membrane lying in folds like the leaves of a book—hence the name "omasum" (omasus, or psalterium). Further, the food enters the fourth section of the stomach—the abomasum (abomasus), which is rich in pepsin glands. In the triple stomach, the "omasum" is absent. In the strongly developed cellular rumen of camels, the water they drink is preserved. The intestine of ruminants, in connection with their diet of plant food, is very long and many times exceeds the length of the body. Many domestic animals domesticated by man belong to the ruminants. The most important families of ruminants are: the family of bovines (Bovidae): bull, bison, muskox; the family of sheep and goats (Ovidae); the family of antelopes (Antilopidae). All of them belong to the hollow-horned ruminants (Cavicornia); their horns are formed by hollow conical horn sheaths mounted on an outgrowth of the frontal bone; as a rule, hollow horns are not shed but grow gradually as they wear down. The family of true deer (Cervidae) has solid, periodically replaced antlers. The young, not yet hardened antlers of the Siberian maral (Cervus canadensis var. asiaticus), called velvet antlers, enjoy fame in China as an aphrodisiacum. The family of musk deer (Moschidae): the musk deer, Moschus moschiferus, has some medical significance, as it provides musk, which is a secretion of the glands of the musk sac; the latter is located in the male anterior to the opening of the prepuce. Musk is used as a stimulant for exhaustion.