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Yak/Angus Cross Ideal For High Elevations
University of Wyoming researcher Mark Stayton is adding Yak genes to Angus to better tolerate high altitudes. Conventional cattle breeds often contract brisket disease at altitudes above 6,000 ft. Stayton thinks one answer is to crossbreed them with yaks native to Tibet.
  “Yaks live on the Tibetan plateau with an average elevation of 14,500 ft.,” says Stayton. “They have multiple mechanisms to provide altitude resistance. We are trying to capture some of them to give our cattle a few thousand feet more resistance.”
  Stayton explains that as North American beef breeds have been bred up for increased meat production, they appear to have become more sensitive to high altitudes. Bovine high-mountain disease or brisket disease is the result. Arteries in the lungs close off in cattle at high altitudes. As blood pressure builds, unable to push blood through the lungs, fluid collects around the lungs, and cattle die of congestion of the lung or pneumonia. In humans, a similar condition is pulmonary hypertension.
  “In the past, we looked for the disease at altitudes of 6,000 ft. or higher, but as cattle have become blockier over the years, the problem altitude appears to be creeping lower,” says Stayton.
  Yaks lack the hyper sensitive reaction. Stayton, an associate professor of Molecular Biology, suspects that fewer genes are involved in it than in other altitude resistant mechanisms. He has crossbred Angus cows with Yak semen to produce a first generation cross. This summer, crossbred heifers will be taken to high elevations and tested for pulmonary pressure.
  “The most resistant will be bred back to Angus bulls and the quarter-yak heifer calves again tested and selected for resistance,” says Stayton. “Eventually we hope to breed out all the yak DNA except for resistance.”
  When the traditional crossbreeding and selection reaches the third or fourth generation, Stayton will begin using a high tech approach. Bioinformatics will be used to analyze and compare each animal’s DNA with mapped genomes of yak and bovine.
  “This will let us identify the regions of the genome we are selecting for, as certain DNA sequences are more prevalent in later generations,” he explains.
  The reason Stayton is attempting to eliminate most yak DNA is to maintain bovine productivity. Yaks are slower growing, are smaller, and mature a year or two after bovines. They are heavily horned and have a long outer coat and a more wool-like undercoat.
  “Meat processors don’t like to deal with the heavy hair coat, which tends to get matted,” says Stayton.
  Contact: FARM SHOW Followup, Mark M. Stayton, Ph.D., Department of Molecular Biology, Dept. 3944, 1000 E. University Ave., University of Wyoming, Laramie, Wyo. 82071 (ph 307 766-4025; stayton@uwyo.edu).


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2017 - Volume #41, Issue #3