European Bison (Wisent) have been crossed with domestic cattle to produce the Zubron. These were first bred in Poland in 1847 as hardy, disease resistant alternatives to domestic cattle. Breeding was discontinued in the 1980s. The few remaining zubron can be found at Bialowieski National Park. First generation hybrid males are sterile, but females may be crossed back to either a wisent or domestic bull to produce fertile males.
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 now intercross with the utmost freedom. All the European breeds have so often been crossed both intentionally and unintentionally, that, if any sterility had ensued from such unions, it would certainly have been detected. [...]The late Lord Powis imported some zebus and crossed them with common cattle in Shropshire; and I was assured by his steward that the cross-bred animals were perfectly fertile with both parent-stocks. Mr. Blyth informs me that in India hybrids, with various proportions of either blood, are quite fertile; and [...] are allowed to breed freely together.
The zebu, now called Bos taurus, is the common domestic cow in much of Asia. They have been interbred with other domestic cattle over thousands of years. Some zebu breeds are derived from hybrids between zebu and yak, gaur and banteng. Zebu breeds have been widely crossed with European cattle. In Brazil, the Chanchim breed is 5/8 Charolais and 3/8 Zebu and combines the Charolais' meat quality and yield with the zebu's heat-resistance.
In Nepal, Tibet, and Mongolia, cattle are crossbred with yaks. This gives rise to the infertile male Dzo as well as fertile females which are bred into cattle breeds. The "Dwarf Lulu" breed of cattle was tested for DNA markers and found to be a mixture of both types of cattle with yak genetics.
A herd of hybrid plains bison x wood bison lived wild in the Yukon, Canada. The Wood bison is a distinct subspecies that almost became extinct in the 20th century. In an attempt to save the Plains bison subspecies, between 1925 and 1928, thousands of Plains bison were released into Wood Buffalo Park (a preserve for the Wood buffalo subspecies). They readily interbred and produced a 12,000 strong herd by 1934. The Wood bison was nearly hybridized into extinction. A small genetically pure herd was recovered from an isolated area in 1959 and is now being kept isolated from introduced Plains bison.