Bovid hybrid
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[edit] Intraspecific Bos hybrids
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 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.
[edit] Bison/Domestic cattle hybrids
American Bison bulls (American "Buffalo") have been crossed with domestic cattle to produce Beefalo and Cattalo. These are variable in type and colour depending on the breed of cattle used e.g. Herefords and Charolais (beef cattle), Holsteins (dairy) or Brahmin (humped cattle). Generally they are horned with heavy set forequarters, sloping backs and lighter hindquarters. Beefalo have been back-crossed to Bison and to domestic cattle; some of these resemble pied Bison with smooth coats and a maned hump. The aim is to produce high protein, low fat and low cholesterol beef on animals which have "less hump and more rump". Although Bison bull/domestic cow crossings are more usual, domestic bull/Bison cow crossings have a lower infant mortality rate (cow immune systems can reject hybrid calves). Modern Beefalo include fertile bulls, making the Beefalo a variety of "improved cattle" with a dash of Bison. There were suggestions of crossing the beefalo to Cape buffalo. Bull and cow cattalos are reported in Wonders of Animal Life edited by J A Hammerton (1930).
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.
[edit] Cattle/Yak hybrids
Among the mountains of Nepal, 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.[1]
[edit] Water buffalo/Domestic cattle hybrids
Water buffalo and domestic cattle cannot hybridize. In laboratory experiments, the embryos fail around the 8-cell stage.
[edit] Bison/Yak Hybrids
The Bison (American "Buffalo") has been bred with the domestic Tibetan Yak to create the Yakalo. In Nepal, Yak/Cow hybrids are bred using Yak bulls on domestic cows or, less often, domestic bulls on Yak cows. The Yak-Cow females are fertile, the males are sterile and the meat is considered superior to beef. In Nepalese, the hybrid is called a Khainag or Dzo (male)/Dzomo (female). A Dzomo crossed with either a domestic bull or yak bull results in an Ortoom (three-quarter-bred) and an Ortoom crossed with a domestic bull or yak bull results in a Usanguzee (one eighth bred). Continued interbreeding means many supposedly pure Yak and pure cattle carry a dash of each other's genetic material.
[edit] Intra-specific bison hybrids
The American bison and European bison (wisent) have been hybridized. This was originally done in a mid-20th century program to reinvigorate the declining wisent population. Modern herd keep hybrids well isolated from pure wisent.
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 hybridised 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.
[edit] References
- ^ Mitochondrial DNA analysis of Nepalese domestic dwarf cattle Lulu, http://www.ingentaconnect.com/content/bsc/asj/2004/00000075/00000002/art00003, TAKEDA K.; SATOH M.1; NEOPANE S.P.2; KUWAR B.S.2; JOSHI H.D.2; SHRESTHA N.P.2; FUJISE H.3; TASAI M.4; TAGAMI T.4; HANADA H., Animal Science Journal, Volume 75, Number 2, April 2004, pp. 103-110(8)
