Virginia Tech researchers reduce embryonic mortality in beef cattle
BLACKSBURG, Va. — Researchers in the Department of Animal and Poultry Sciences at Virginia Tech believe they have found a way to reduce embryonic mortality rates for cows bred by timed-AI. This finding is expected to help beef cattle producers immediately.
Dr. Vitor Mercadante and his doctoral student, Claire Timlin, have been looking at possible feed supplements to be given following timed-AI in B. taurus beef cows. They are collaborating with Dr. Reinaldo Cooke at Texas A&M University.
The problem researchers looked at was an increased loss of embryos in cows within 30 days of being bred. The research has discovered that the problem is occurring between 14 and 16 days of breeding. Their goal, according to Mercadante, was to figure out how to improve the embryo-maternal crosstalk to ensure pregnancy establishment.
The answer they found seems to be supplementation with Calcium salts of soybean oils. They were able to increase pregnancy rates by nine percent, he reported.
During an interview here he reported that Timlin did several studies supplementing omega-6 fatty acids to cows post-AI.
“What we’ve seen when cows are fed some supplement rich in omega-6 is that uterine environment is improved and embryos are better at signaling their presence to the cow, which improves pregnancy establishment, reduces embryonic mortality and increases pregnancy rates after AI,” he said.
Two studies of about 1,000 cows located were located in Virginia and Oregon.
Timlin conduced two experiments dealing with this problem during her research and collaborated in another with the researchers at Oregon State University and Texas A&M. In one of the studies performed in Virginia a total of 771 lactating multiparous Angus cows. They were divided into 22 groups of approximately 35 cows per group.
Some received the omega-6 supplement mixed with half-pound of cracked corn used as a carrier to ensure consumption and some received the carrier but not the supplement of omega-6. The supplements were fed 21 days starting at the day of AI.
At day 30 the cows underwent transrectal ultrasonography which showed those receiving the soy oil supplement had a higher pregnancy rate than those that did not. There was a nine percent improvement in pregnancy rates.
In the second, she used 90 multiparous Angus x Hereford cows housed in 18 drylot pens and given the same time-AI and treatments as those in the first experiment. In this one, the cows were subjected to several medical procedures to determine hormone levels, signs of pregnancy and confirmation of pregnancy.
The researchers concluded from the experiments that post AI CSSO supplementation to beef cows improved the embryo’s ability to signal its presence to the cow, as well as the uterus receptivity to the embryo, resulting in increased pregnancy rates to timed-AI compared to non-supplemented cows.
“My job is to make cows happy,” Mercadante said, maintaining that a pregnant cow is a happy cow and a pregnant cow means a happy farmer.
Additional information on using this supplement in beef cattle herds can be obtained through local Virginia Cooperative Extension offices across the state.
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