ECOLOGICAL AND MORPHOLOGICAL CHARACTERISTICS OF THE YAK‘S INTESTINE IN ONTOGENESIS
The article presents yak's intestine’s growth and development data during ontogenesis, which are subject to the General laws of development of mammalian. During the uterine period the mass and length of the intestine grows faster than the body weight. In the second half of uterine period the development and specific differentiation of intestinal wall membranes is continues. In the postnatal period continues further differentiation and development of morphological and functional structures of the intestine, increase the growth of mass and length of the intestine. The results of studies have shown that a large length of the intestine of the Yak in comparison with cattle is a consequence of the inaccessible pastures, the vegetation of which contains more fiber, less digestible protein and minerals, which causes elongation of the digestive process in the intestine and difficulties in extracting nutrients from such feed.