Toxin Topic: Slaframine Intoxication

The wet spring weather and abundant clover growth in Central Kentucky has made 2010 a bumper year for slaframine toxin, or "slobber toxin."

Slaframine is a mycotoxin produced by the fungus Rhizoctonia leguminicola. This fungus can be present on clover, alfalfa, and other legumes. Cool, wet, humid weather promotes growth of the fungus and production of slaframine. Many cases of slobber syndrome are associated with feeding affected legume hays. All animals are sensitive to the toxin's effects. In horses, excessive salivation is usually the first sign of slaframine exposure. Signs typically develop within hours of exposure. Other signs include feed refusal, diarrhea, colic, and decreased milk production in lactating animals. Signs are usually mild to moderate and generally do not result in any life-threatening problems. Slaframine's effects are caused by stimulation of the parasympathetic nervous system (PNS, the part of the nervous system responsible for the "rest and restore" response). Most cases resolve quickly after removal of the contaminated feed source, but more severe cases might require treatment such as supportive fluids and the drug atropine.

If slaframine intoxication is suspected, the hay or forage can be examined for evidence of Rhizoctonia leguminicola contamination and can also be tested for slaframine. Rapid recovery from clinical signs after hay removal or removal of the animal from a pasture containing clover or other legumes supports a presumptive diagnosis of slaframine intoxication. Owners should contact their veterinarian right away if they notice animals with excessive salivation, because many other causes of hypersalivation exist.

Cynthia Gaskill, DVM, PhD, clinical veterinary toxicologist at the Livestock Disease Diagnostic Center provided this information.

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