Dateline: November 23, 2006

Toxin in corn may be deadly to horses

By Roger Estlack, Clarendon Enterprise

AMARILLO – Conditions in corn fields across the High Plains were right this year to produce a deadly toxin already responsible for the death of two horses in the Panhandle, said a Texas Veterinary Medical Diagnostic Laboratory official in Amarillo.

Dr. John Haliburton, head of diagnostic toxicology for the vet lab, said fumonisin has been found in a random sample of corn by the Texas State Chemist Office at Texas A&M University in College Station, and in two samples he tested in Amarillo. 

Fumonisin comes from a mold in corn. The fungus that produces the toxin is found in every corn field, however the toxin only materializes under ideal conditions.

“This past growing season, the temperatures and ample moisture early were ideal to produce the toxin,” he said. 

Horses are the most sensitive to this toxin, with pigs the next most sensitive. Cattle are not as sensitive, and therefore, can eat corn that is not suitable for horses or pigs.

Corn that is going into a horse ration should not have more than 5 parts per million of the toxin. The total ration that includes the corn cannot have more than 1 part per million, Haliburton said. The three corn samples he tested had more than 20 parts per million. 

Horses that eat the toxic corn develop lesions in their brains, causing blindness that can occur overnight, staggering, extreme depression or extreme agitation and finally death, he said. In pigs, the toxin affects the lung and causes massive edema.

“It’s 99.9 percent fatal. We’ve already had two horses die from this disease,” Haliburton said. “My concern is with the problems we’ve been having with horses and West Nile Virus, this might get misdiagnosed. I’m advocating anyone who is feeding corn from the Texas High Plains to horses should get it tested.”