What is "grunting cow"

Yak \Yak\ (y[a^]k), n. [Tibetan gyag.] (Zo["o]l.) A bovine mammal ( Po["e]phagus grunnies) native of the high plains of Central Asia. Its neck, the outer side of its legs, and its flanks, are covered with long, flowing, fine hair. Its tail is long and bushy, often white, and is valued as an ornament and for other purposes in India and China. There are several domesticated varieties, some of which lack the mane and the long hair on the flanks. Called also chauri gua, grunting cow, grunting ox, sarlac, sarlik, and sarluc.

Yak lace, a coarse pillow lace made from the silky hair of the yak.