Some Top Race Horses Are Proving to Be Duds as Studs

Increasing numbers of high-priced breeding stallions are turning into duds as studs, suffering from sexual problems that appear to be caused by drugs and unnaturally stressful training programs, researchers say.

Between 20% and 25% of the stallions brought to the University of Pennsylvania for stud evaluation exhibit mating behavior problems, many of which mimic human sexual dysfunction, said Sue McDonnell of the veterinary school’s reproductive studies program.

“It appears to be pretty common and probably is on the increase,” McDonnell said. “We’re seeing a lot of stallions who either have no interest in mares--stargazers we call them.” McDonnell, speaking at the annual meeting of the American Veterinary Medical Assn., said the situation was a serious one because much of horse economy depends on the best stallions being able to procreate.

“These are very expensive animals,” McDonnell said. “The dud stud problem has really caused quite a bit of concern in the circuit, even though it’s something trainers and owners are really reluctant to talk about.”

Fortunately, the horses respond well to the same kind of treatments that sometimes work for humans--appropriate behavior therapy and the use of antidepressants and anti-anxiety drugs, she said.

“It’s a very delicate situation for the horse, just like it is for humans,” McDonnell said. “One negative sexual encounter can create something in a stallion that looks like frank neurosis.

“But once a stallion has a happy, successful breeding, they’re usually cured.”

McDonnell said the most common problem among stallions is simple lack of interest.

“They’ll be presented with a mare in estrus (heat), and they’ll just stand in the corner and paw at the ground,” she said. “It’s a pathetic sight, and sometimes owners and trainers will completely disassociate themselves from the animal after something like that.”

The root of the problem appears to be the use on racing circuits of anabolic steroids, artificial hormones that boost performance but suppress the animal’s own natural hormones, McDonnell said.

Giving the stallions tricyclic anti/depressants appear to restore their libido, just as it does in some humans who take the drugs. However, in humans, tricyclic anti-depressants also sometimes reduce libido.

Another major breeding difficulty is that many stallions are forced into premature and stressful training programs, making them nervous and uncomfortable around mares. Diazepam, a tranquilizer best known under its trade name Valium, often calms the stallions enough to facilitate mating.

“But you have to be careful not to give them too much,” McDonnell said. “Horses need to keep all their wits about them in order to achieve intercourse.”