Dzo Dzo A dzo (Tibetan མཛོ་ mdzo) (also spelled zo, zho and dzho) is a hybrid between the yak and domestic cattle. The word dzo technically refers to a male hybrid, while a female is known as a "dzomo" or "zhom". In Mongolian it is called khainag (хайнаг). There is also the English language portmanteau term of yattle, a combination of the words yak and cattle, as well as yakow, a combination of the words yak and cow. Dzomo are fertile (or, fecund) while dzo are sterile. As they are a product of the hybrid genetic phenomenon of heterosis (hybrid vigor),
Bovid hybrid also cross with bison; the hybrid offspring are occasionally kept by farmers in northern Alberta where the snowy, cold winters necessitate a cold-hardy animal. In Tibet and Mongolia, yaks are quite often crossbred to dairy cattle, the result being known as "dzo" or "zho". The offspring are used as milk cows, if female, or as oxen, if male. In "The Variation of Animals and Plants under Domestication" Charles Darwin wrote: "Bos primigenius" and "longifrons" have been ranked by nearly all palaeontologists as distinct species; and it would not be reasonable to take a different view simply because their domesticated descendants