Should Angular Limb Deformities In Foals Cause Concern?

Learning how to identify and effectively monitor angular limb deformities in foals may help save you money while creating a stronger athlete.

More often than not, a foal has some degree of angular limb deformity at birth. But will the issue resolve itself naturally, or does it require assistance? Evaluating the degree of severity of the deformity within the first few weeks of the foal’s life helps an owner develop a plan for treating the afflicted limb.
   
Angular limb deformities take two forms—those that are congenital and those that are acquired. Acquired deformities occur sometime after the foal is born and can be the result of an injury or inflammation of the growth plate or just the natural conformation the foal will develop. Congenital deformities are present at birth and may be the result of how the foal is positioned in the uterus. These deformities are then further categorized as either valgus (the limb below the joint described deviates laterally, or to the outside of, the axis of limb) or varus (the limb below the joint described deviates medially, or to the inside, of the axis of the limb).
   
Due to a foal’s cramped placement within the mare’s uterus, it is not unusual for a newborn to exhibit a varus or valgus deformity, and some of these foals will naturally correct without human assistance. An example of one such deformity is carpal valgus (knock kneed), which, if not severe, can straighten without medical intervention. However, some deformities, such as fetlock varus (bow legged), require immediate medical attention.

Evaluating The Foal

“Most foals are not born straight,” said Alan Ruggles, DVM, ACVS, who, since starting his work in veterinary medicine more than 20 years ago, has treated thousands of foals with angular limb deformities at Rood And Riddle Equine Hospital in Lexington, Ky. “Limb deformities result from a combination of muscular and ligament weaknesses, so it is necessary to be cautious in labeling a foal within the first two weeks of life because most limbs change dramatically once they become weight-bearing.”
   
Brooke Royster, owner of Chance Farm in Gordonsville, Va., has been breeding Thoroughbreds for three decades and has seen hundreds of foals born.
   
“When I see a foal born with certain more minor deformities like slightly knock kneed, I tend not to worry too much because I know that if the deformity is not too severe that it is apt to correct in time,” he said. “But if I don’t see improvement in the first month or so then I might consider a more aggressive approach.”