Clemson University Discovery Could Be Used For Fescue Toxicosis

A medication used to treat nausea is now helping horse breeders produce healthier mares and foals and may someday help address problems of infertility in humans. Dee L. Cross, a Clemson University animal scientist, hypothesized that the medication, now patented as Equidone, could be useful in treating a condition called fescue toxicosis in pregnant mares.

Fescue toxicosis is caused by a fungus that infects fescue grass pastures and results in severe reproductive problems, including spontaneous abortions, prolonged pregnancy, difficulty giving birth, and no mild production. Many times the foal is stillborn or dies shortly after birth; the mare can also die or have to be destroyed because of complications during delivery.

In the horse racing industry, where stud fees are measured in six figures and sale prices can reach several million dollars, there is little margin for error in breeding programs. Aside from the investment aspect, both professional breeders and private individuals want to protect the health and well-being of their horses.

“We studied the cellular action of the alkaloids produced by the fungus-infected fescue grass,” Cross said. “The alkaloids were activating dopamine receptors that this drug was known to block when used to give relief from nausea in humans.”

The researchers tested their theory in the laboratory and found that Equidone did in fact block the activity of alkaloids extracted from the contaminated grass. They then moved to testing the treatment on horses grazing on fescue pastures and got positive results in the very first study.

The medication is now being tested by veterinarians around the country under an experimental permit from the federal Food and Drug Administration.

The results are very promising. Mares treated with the medication for 10-15 days before their anticipated foaling date are delivering healthy foals without complications and producing a normal mild supply after delivery. The medication also increases milk production in mares not suffering from fescue toxicosis.

“We think Equidone has implications for medical uses beyond horses, including humans,” Cross said.

The medication has the added benefit of stimulating production of follicles on the ovaries, suggesting that it could be used to treat problems of infertility in humans, as well as to increase the reproduction rate in horses and other livestock.

The Food and Drug Administration is now reviewing research results, with the possibility of full approval by the end of the year. A new company, called EquiTox, has been formed to continue development of the medication under an agreement between the company and Clemson University. This research is funded through Clemson's Agriculture and Forestry Research System, as well as by the company.

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