Flexure Tendon Laxity in The Newborn Foal

Musculoskeletal abnormalities are often present in the newborn foal. Many of these abnormalities are self-limiting and benefit from benign neglect. The problems become more serious when the deformity inhibits the foal's ability to seek and receive colostrum and nourishment. Some of the most common deformities that we see involve the flexure tendons.

Lax flexor tendons are the most common disorder seen in the newborn foal. It may be a misnomer to call this problem a tendon laxity. The laxity originates in the muscles rather than the tendons. The laxity can vary in degree from a slight dropping of the fetlock to a severe weakness with the foal walking on the back surface of the fetlock with the toes pointing into the air. Tendon laxity can be present in all four limbs. Though most commonly seen in the fetlock and pastern, it can also be seen in the carpus (knee). It appears to involve the rear limbs with greater frequency.

The cause of this congenital weakness is unknown. Lack of musculoskeletal stress or tension in utero may play a role in its development. Premature foals are more likely to have lax tendons. Foals that are born without laxity can acquire it if they become debilitated for some other reason.

Diagnosis

The diagnosis of this problem is evident on examination of the foal. No special tests are necessary. If the foal appears premature you may wish to radiograph the limbs to determine if the carpal bones are completely ossified.

Treatment

No specific treatment is needed in the first week or two of life. As the foal becomes more coordinated and agile, the muscle tone increases and tightens the tendinous structures. In the cases where the foals are walking on the bulbs of their heels or on the back of the pastern, a light tape bandage may be needed to prevent abrasions to these regions. Heavy bandaging of the legs is not indicated. Bandaging or splinting will result in disuse of the leg muscles, weakness and increased laxity.

If time and increased muscular activity does not resolve the laxity, then corrective trimming and shoeing may be appropriate. Often the heels of the foot have overgrown and need shortening. This can be done with a few passes with a hoof rasp. A small shoe with a 1.5-inch heel extension can be applied to the foot. This will effectively lower the toe and raise the fetlock. The size and softness of the hoof wall makes attachment of the shoe to the foot difficult. Temporary heel extensions can be devised out of tongue depressors and taped to the hoof wall with duct tape. It has been recommended to fashion the shoe out of plywood and attach it via wires placed through holes drilled into the hoof wall. I have had better luck with the newer glue on shoes, which can be made to fit the foal's foot.

Home Care and Prevention

Foals should be allowed controlled exercise. A few hours of turnout in a small paddock daily will help to strengthen muscles, which in turn will appear to tighten the tendons. Check the bulbs of the foal's heels and the back of her pasterns for any abrasions or sores. If there is any wounds they should be cleaned with a mild soap and then protected with a light bandage held on by a piece of duct tape. Do not apply a leg wrap. Support wraps will actually increase the laxity instead of improving it.

If the tendon laxity interferes with the foal standing and nursing on her own, then you may need to intervene until the foal is able to stand without assistance. It is very important that the foal receives the mare's first milk, colostrum, which is rich in necessary antibodies for the foal. The foal should receive colostrum within the first three hours of birth.

There is no way known to prevent this problem.