U researchers discover gene that kills baby horses

The genetic disease occurs in quarter horses and similar breeds.

Hayley Odom

Horses are professor Stephanie Valberg’s passion.

For the last five years, she and other veterinary medicine researchers at the University have been working to find out why some horses die shortly after birth.

This summer, they identified the cause as a genetic disease which occurs in quarter horses – small horses known for their sprinting ability – and similar breeds. It causes blood sugar in baby horses, or foals, to drop, causing them to die.

The discovery led to a new test that can screen horses for disease-causing traits.

“We have an explanation for owners about the cause of the problem,” Valberg said. “It provides them with information on an inherited disease Ö and it gives them the ability to never have this happen again.”

The disease occurs when two horses mate and both

carry the recessive trait that causes the disease, said Jim Mickelson, researcher and professor of veterinary biosciences.

For $35 per horse, breeders can test their stallions and mares for the trait and prevent mating in horses that could pass the traits on to their offspring, Valberg said.

She said the discovery will save horse breeders from emotional and economic loss.

“Most breeders look at it as a way to avoid this traumatic death and emotional connection,” she said. “The biggest financial impact is knowing that a stallion has it and could pass it on. You can find out if the animal has the trait and not use it for breeding anymore.”

She said horses born with the disease could appear normal for up to two months and then suddenly die. Others, she said, might be born weaker than normal or have crooked legs.

Mickelson said breeders often attribute the deaths to nature.

“Genetics doesn’t always leap into people’s mind as a cause of a foal dying, so this information will take a while to sink in,” he said. “But people are making use of it. We’re getting samples in every week.”

Ten percent of all quarter horses in the United States are carriers of the defective gene, Mickelson said.

He said 50,000 horses per year could be affected by this disease.

Buddy Fisher, a horse breeder and trainer in Abilene, Texas, said that as far as he knows, his foals have never died of the disease. But the test will be a valuable tool for breeders experiencing the problem, he said.

“If people are losing foals, it would be a great benefit to them,” he said. “By the time you get ready for that baby to be born, you already have a year invested in it. A test like that is a great test.”