Being unfamiliar with “Khainag”, of course we went to Google.  Abridged from Wikipedia, “A dzo (Standard Tibetan) 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 a khainag (хайнаг). There is also the English 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, while dzo are sterile.”  All clear now?  Unused Mongol Post card.  Grade: 1