Page 56 - New Mexico Winter 2021

by Megan Petty, DVM
It’s that time of year again; time to start planning and preparing for foaling season. Doesn’t it feel like we just wrapped up
the 2021 foaling season? Yet here we are,
on the cusp of 2022. Angular and flexural
limb deformities, and laxity are common conformational problems seen at or soon after birth in foals. Previously, I have discussed neonatal illnesses and foaling complications and you’ll likely see crossover and correlation to points from those previous articles here as well. The following is provided in hopes that you’ll feel more comfortable in knowing how to proceed should you have a foal born with any combination of these issues.
Angular limb deviation or deformity
(ALD) is not an uncommon problem. In
fact, most foals are born with some degree
of limb deviation. This deviation, usually referred to as “crooked legs”, is often due
to ligament laxity or muscle weakness in newborn foals and will resolve on its own
as the foal exercises and becomes stronger.
As with most congenital issues in our foals, there are numerous potential causes. In the
case of ALD, the causes fall into 2 categories: perinatal and developmental. According to
the American College of Veterinary Surgeons (ACVS), the perinatal causes include premature birth, twin pregnancy, placentitis (infection/ inflammation of the placenta), perinatal soft
Above, left: Limb deviation, usually referred to as “crooked legs,” is often due to ligament laxity or muscle weakness in newborn foals and will usually resolve on its own as the foal exercises and becomes stronger. Above, right: A knock-kneed foal is referred to as having a “carpal valgus” angular limb deviation (ALD) since “valgus” refers to an outward angulation where the limb below the knee is angled out. – Photos provided
tissue trauma and flaccidity, or laxity of the soft tissue around the joint.
Developmental causes include imbalanced nutrition, excessive exercise and trauma.
Thankfully, diagnosis of an angular limb deformity is quite simple. When viewed from either the front, back or side, you should be able to draw an imaginary line from the top of the leg to the ground straight through the limb. If there is a break and change in direction of that imaginary line, you’ve found an ALD. Since
these deviations involve the change in direction
of the limb toward or away from midline, these angulations are referred to as either varus (inward) or valgus (outward). The affected joint is included in this description, so you’ll hear a knock-kneed foal referred to as having a “carpal valgus” ALD. The carpus (what we horse owners call the knee) appears to be angled in, but the portion of the limb below the knee is angled out.
Diagnostics performed by your veterinarian will determine the location and degree
“Remember, time and your veterinarian are your friend when dealing with limb abnormalities in your newborn foal.”
54 New Mexico Horse Breeder
Common Limb Abnormalities Of Newborn
Foals