Cattle were originally identified by Carolus Linnaeus as three separate species - Bos Taurus (European domestic cattle, including his kind in Africa and Asia), Bos indicus ( zebu ) and the extinct Bos primigenius ( wild European tour . Nowadays it is considered that the tours are ancestors of European cattle and zebutata, and increasingly all three forms are identified as subspecies of one species, Bos primigenius (respectively Bos primigenius Taurus , Bos primigenius indicus and Bos primigenius primigenius ).
Systematics of domestic cattle is complicated by the ability to roam successfully with related species. There are hybrid individuals and even breeds derived from crosses of European cattle not only zebu but also with other animals of the genus Cattle by yak , banteng and Gaur . It is even possible hybridization with one of the two types of bison that are not usually included in the genus Cattle. At the same time domestic cattle can not be crossed with some more distant members of the subfamily of cattle as kafarskiya and domestic buffalo . The hybrid origin of some forms of domestic cattle is not obvious. For example, genetic studies have shown that breed Dwarf Lulu , the only cattle without hump in Nepal are a hybrid of European cattle, zebu and yak.
Originally the tour, the supposed ancestor of domestic cattle is widespread in Europe , North Africa and much of Asia . Historically, extending range is limited to a part of Europe, the last known specimen died in Poland around 1627. Attempts by hybridization to create a home ox-like appearance of the tour, the result of which breed Heck .