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Reproductive Concerns When Grazing or Feeding Small Grain Forage

Livestock Update, June 1998

John Hall, Animal and Poultry Sciences, Virginia Tech

Recently, a large advertisement was placed in a Virginia agricultural magazine warning that grazing or feeding rye forage would cause abortions and infertility in cows. Although this ad was directed primarily at dairy farmers, the inference was that beef cows could be affected also.

I contacted the individual who placed the ad. Although he recounted several anecdotes, he did not send me any data even though I requested it. Personally, I strongly question the cause and effect relationship between rye and the reproductive failures claimed.

However, a brief review of the effects of feeding or grazing small grains may supply you with research based information to answer your clients questions. The results from the published literature are as follows:

  1. Small grain forage and other extremely digestible forages contain high levels of rumen degradable protein.

  2. When these proteins are rapidly degraded in the rumen, they produce high levels of ammonia.

  3. In dairy cattle, high levels of rumen degradable protein and ammonia are associated with increased early embryonic mortality. The increase in early embryonic mortality appears to be a result of a uterine environment that is unsuitable for the embryo.

  4. The problem of high rumen degradable protein or ammonia is increased in cows that are in negative energy balance (thin or losing weight). It takes energy to rid the body of excess ammonia or protein.

  5. Cows on small grain forage or high levels of protein DO cycle properly and express heat normally. They DO NOT have uterine infections, abort already implanted fetuses (30 days + after conception) or become sterile. Few direct studies have been performed in beef cows on this subject.

If you have clients that believe their herds have reproductive problems as a result of grazing small grains, you should follow the same basic procedure as you would for any reproductive problem. First gather as much background information as possible including nutrition program, cow body condition score, stage of production, breeding programs, and bull fertility. Contact Dr. Dee Whittier or me if you need additional assistance with these calls.

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