Contracted Tendons in Lambs: Bent Legs, Knuckling, and Treatment

Contracted tendons in lambs are usually described as a flexural deformity of one or more limbs. In practical terms, the tendons and surrounding soft tissues are too tight, so the lamb cannot fully straighten the affected joint. Pet parents and producers often notice bent front legs, tiptoe standing, or knuckling over at the fetlock or carpus soon after birth.

Severity varies. A mildly affected lamb may still stand and nurse, although awkwardly. A more severely affected lamb may struggle to rise, bear weight on the front of the pastern or fetlock, or develop skin sores from abnormal pressure. Some lambs improve quickly with early support, while others need more hands-on veterinary care.

This problem can be congenital on its own or part of a broader developmental issue. It is important not to assume every weak or bent-legged newborn has contracted tendons. Lambs with fractures, nerve injury, selenium deficiency, infection, or more generalized congenital abnormalities can look similar at first, which is why a veterinary exam matters.

There is not one single cause. In some lambs, the deformity appears to be an isolated congenital problem affecting the flexor tendons and nearby soft tissues. In others, it may be linked to fetal positioning in the uterus, inherited tendencies, developmental mismatch between bone growth and soft tissue length, or reduced movement before birth. Merck also notes that some congenital anomalies in sheep and goats can involve musculoskeletal abnormalities, and environmental teratogens can cause fetal contracture defects in ruminants.

Your vet may also consider maternal toxin exposure during pregnancy. Merck lists poison hemlock as a cause of contracture defects in cattle, goats, sheep, and pigs. Infectious causes of congenital deformity are also part of the differential list in some regions, especially when there are multiple affected newborns or other birth defects in the flock.

Not every lamb with bent legs has true tendon contracture. White muscle disease from low selenium and possibly vitamin E can cause stiffness and weakness in lambs, which may make them stand abnormally. Trauma during a difficult birth, fractures, septic joints, and neurologic disease can also mimic contracted tendons. That is why treatment should be based on an exam, not appearance alone.

Diagnosis starts with a hands-on newborn exam. Your vet will watch the lamb stand and walk, feel the joints and tendons, check whether the limb can be gently extended, and look for pain, swelling, instability, or skin injury. They will also assess whether the lamb is bright, warm, nursing well, and has received colostrum, because supportive care can be just as important as the limb problem itself.

The key question is whether this is an uncomplicated flexural deformity or something else. Your vet may recommend radiographs if there is concern for fracture, angular deformity, or joint malformation. If the lamb is weak or stiff overall, bloodwork or flock-level history may help evaluate for nutritional muscle disease, infection, or congenital syndromes.

In more complex cases, diagnosis also includes looking beyond the individual lamb. If several lambs are affected, your vet may review breeding history, ewe nutrition, mineral program, pasture and weed exposure, vaccination status, and regional infectious risks. That broader picture helps guide both treatment and prevention.

Prevention starts before lambing. Work with your vet to review ewe body condition, trace mineral program, forage testing, and regional deficiencies, especially selenium status where deficiency is known to occur. Merck notes that white muscle disease in sheep is caused by low selenium and possibly vitamin E, and preventive mineral planning may include properly formulated trace mineral supplementation or, in deficient areas, vet-directed vitamin E/selenium strategies.

Pasture and hay management also matter. Pregnant ewes should be protected from known teratogenic plants, and Merck specifically lists poison hemlock as a cause of fetal contracture defects in sheep and other livestock. If you have repeated cases, ask your vet to review grazing areas, stored feed contamination, and any medications or unusual exposures during gestation.

At the flock level, keep records. Note whether affected lambs are tied to a specific ram, ewe family, pasture, or lambing group. Recurrent cases can point toward heritable risk, nutritional imbalance, or a shared gestational exposure. Early lambing checks are also preventive in a practical sense: the sooner a bent-legged lamb is identified, helped to nurse, and examined when needed, the better the chance of a functional recovery.