Tendon contracture and laxity problems in foals common, but still serious
Tendon contracture and laxity in foals is not an uncommon problem and one that most equine practitioners routinely deal with just about every foaling season.
There always seems to be at least one foal that is born with one of its parts too tight, too loose or somehow out of place.
Ears, noses, tongues and tails have also all been reported to have suffered some degree of contracture or laxity in young foals. Most owners are quite concerned about the abnormal appearance of their recent arrivals and an explanation and treatment options are usually sought.
This explanation is reasonable for contracture, but does little to explain laxity. Occasionally, some foals may be born with both contracture and laxity, which makes the pathogenesis of these conditions even harder to explain.
"Uterine malposition is the most plausible explanation, and the one most readily accepted by clients," says Dr. Andrew Parks, professor of surgery at the University of Georgia College of Veterinary Medicine. "However," adds Dr. Parks, "it is the explanation that is probably the most difficult to support from a research standpoint." Many veterinarians now believe that there are a host of factors, many probably interactive, that all contribute to cases of congenital contracture and laxity. Veterinarians seeking to assist their clients in determining the causes of these problems and in reducing the chances of reccurrence in breeding programs, need to be complete in their investigation of other possible factors.
Plants and toxins Numerous case reports in the literature describe tendon contracture in foals born to mares that were exposed to various plants and toxins. Locoweed, Sudan grass and other plants have been reported.
Genetics may be more of a factor than was previously thought, and there is hope that new advances in gene mapping will shed some light on the exact reasons for the development of contracture and laxity. Until then, it is important to control those factors that have already been identified and to aggressively treat these twisted foals when they occur.
Weak flexor tendons Many foals are born with flaccid or weak flexor tendons. The hind feet of these foals are usually affected, though the front feet can be involved as well.
The typical foal is bright and alert, but when it stands it places the palmar (plantar) surface of the hoof on the ground and the toe does not bear weight. In severe cases, the caudal surface of the fetlock may actually contact the ground.
There is a relatively rare condition of extreme laxity in the interphalangeal joints of young foals. The cause of this condition is unknown, and these foals do not respond to treatment. Dr. Ted Stashak, professor of surgery at Colorado State University College of Veterinary Medicine, advises that the only way to differentiate this rare condition from the more commonly seen laxity is to monitor improvement in each foal. Digital photos allow an accurate measurement of angulation changes so that even very slow positive improvement can be noted.