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A GettingReadyFor
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Experts Preparing
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Q: Why is tall fescue pasture bad for my broodmare?
A: Tall fescue is a species of grass that is used in pastures be-
cause of its ability to withstand the grazing pressures of livestock. Some tall fescue varieties have an endophytic fungus invisible to the human eye that produces toxins. If the toxins are ingested, they can cause reproductive problems in your broodmare that can ultimately lead to the death of your mare, foal, or both. One action of the toxins is to interfere with normal dopamine secre- tion in the brain, which prevents the broodmare from producing milk prior to foaling. This is a bad situation because the newborn foal needs to drink colostrum to ingest important antibodies im- mediately following birth to help it fight infection during the early months of its life. Another problem associated with mares ingesting endophyte-infected tall fescue is a prolonged gestation period. The longer gestational period allows the foal and the pla- centa to grow larger in the mare, contributing to a difficult birth known as dystocia, which makes an unassisted foaling difficult for the mare. When the placenta grows, it gets thicker and heavi- er, which can cause it to separate from the uterus, cutting off the foal’s oxygen supply, leading to suffocation. Also a heavier pla- centa may be retained in the mare after foaling, which may cause There are precautions that every horse breeder should take at least 6 months prior to the mare’s expected foaling date. First, breeders should examine their pastures for tall fescue and if pres- ent, have it tested for the fungus. Maryland Cooperative Ex- tension agricultural educators in the counties can help with this process. If endophyte-infected tall fescue is present in the brood- mare’s pasture, eliminate the broodmare’s exposure to it at least 60–90 days prior to foaling. Ways this can be accomplished are to move broodmares to pastures free of tall fescue or feed hay not containing tall fescue on a dry lot. Serious horse breeders should reestablish pastures without infected tall fescue. There are endo- phyte free and safer endophyte varieties of tall fescue not associ- ated with causing reproductive problems available on the market. If the broodmare has been exposed to endophyte-infected tall fescue and is past her foaling date, tall fescue should be removed from her diet and the vet should be contacted immediately. A drug called domperidone will most likely be given by the veteri- narian to initiate milk production. Parturition may need to be ini- tiated depending on how many days the broodmare is overdue.
Prevention is the best key to avoiding tall fescue toxicosis in broodmare. For more information, call your local county MCE agricultural educator or your veterinarian.
Got a Question? Get an Answer! Equiery readers can
ask questions about their horses or horse farms and a panel of experts with the
University of Maryland and Cooperative Extension Services will answer them. If
you would like the panel to answer your question directly, you must e-mail
it to Dr. Amy Ordakowski Burk at [email protected] or Erin Petersen at
[email protected] or, you can fax your question to 410-489-7828 or mail
it in to P.O. Box 610, Lisbon, MD 21765, and the questions will be forwarded to
the panel, but only e-mailed questions will be answered directly. Written ques-
tions only will be accepted, and select questions may be used for publication
in an upcoming Equiery.
www.equiery.com | 800-244-9580 MARCH 2004 | THE EQUIERY | 23

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