Arthrogryposis Multiplex in Cows

Arthrogryposis multiplex is a congenital birth defect in calves. The name describes multiple joints that are fixed or contracted at birth, so the legs may look bent, twisted, or locked in place. In cattle, the condition is often noticed at calving because the calf cannot extend its limbs normally, may be unusually small and thin, and may have other body abnormalities.

This is not one single disease with one single cause. In some herds, arthrogryposis multiplex is linked to an inherited recessive defect, especially the well-known AM defect in Angus and Angus-influenced cattle. In other cases, it can happen when a fetus is exposed during pregnancy to infections that damage the developing brain, spinal cord, or muscles. When fetal movement drops during development, joints can become fixed in abnormal positions before birth.

For the cow, this condition can also create a calving problem. A malformed or rigid calf may not pass normally through the birth canal, increasing the risk of dystocia and the need for prompt obstetric help. That means the condition affects both calf welfare and the dam's safety.

If you suspect this problem in a newborn calf or during a difficult delivery, contact your vet promptly. Early assessment helps your vet guide humane care for the calf and next-step herd decisions for breeding and prevention.

Arthrogryposis multiplex develops when the fetus does not move normally during pregnancy. That reduced movement is usually a downstream effect of abnormal development of the nervous system, muscles, tendons, or joints. In practical terms, the calf's limbs stay in one position too long while growing, and the joints become fixed.

One important cause in cattle is genetic inheritance. The best-known example is the Angus AM defect, an inherited recessive condition recognized in Angus cattle and Angus-influenced lines. Affected calves are often born dead or die soon after birth, with crooked or twisted limbs, fixed joints, poor muscle development, and sometimes a cleft palate. Because it is recessive, normal-appearing carrier animals can pass the mutation to offspring if both parents contribute the defective gene.

Another major cause is fetal infection during pregnancy. Merck Veterinary Manual notes that viruses such as Akabane virus, Schmallenberg virus, bluetongue virus, and bovine viral diarrhea virus can cause congenital defects in calves, including arthrogryposis, especially when infection happens during specific windows of gestation. These infections can damage the fetal brain and spinal cord, which then reduces fetal movement.

Less commonly, arthrogryposis can appear as part of broader congenital syndromes involving pituitary, spinal, or skeletal abnormalities. Your vet may look at breed, breeding history, geography, insect exposure, vaccination history, and whether one calf or multiple calves are affected to narrow down the most likely cause.

Diagnosis usually starts with a physical exam of the calf and a careful review of the calving event. Your vet will look for fixed joints, twisted limbs, spinal curvature, poor muscle mass, cleft palate, and signs that the calf also has neurologic or brain abnormalities. If the problem is discovered during dystocia, the delivery findings themselves can be an important clue.

Your vet may also ask about breed and family history, especially if the calf is Angus or Angus-influenced. If an inherited defect is possible, DNA testing of the calf, sire, dam, or related animals may be recommended through approved cattle genetic testing programs. This can be especially useful when herd breeding decisions need to be made quickly.

If the calf is stillborn or dies shortly after birth, a necropsy often provides the most useful information. Postmortem examination can document the pattern of limb contracture and identify associated defects in the brain, spinal cord, palate, or skeleton. In some situations, your vet may also submit tissues for laboratory testing to investigate infectious causes such as pestiviruses or arboviruses.

A confirmed diagnosis is not only about naming the defect. It helps your vet advise on the dam's recovery, the chance of recurrence, whether herd mates are at risk, and what prevention steps make sense for the next breeding season.

Prevention depends on the underlying cause. If your vet suspects a genetic form, the most important step is to avoid mating two carrier animals. In Angus or Angus-influenced herds, that may mean reviewing registration records, defect status, and DNA test results before breeding decisions are finalized. A single affected calf can be the clue that a hidden recessive mutation is present in the herd.

If your vet suspects an infectious cause, prevention focuses on herd health and pregnancy management. That can include reviewing vaccination protocols, limiting exposure to replacement animals from unknown health backgrounds, and strengthening biosecurity around breeding females. For vector-borne viruses, your vet may also discuss seasonal breeding strategies and ways to reduce exposure to biting insects where those diseases are relevant.

Good calving management also matters. While it does not prevent the defect itself, close monitoring of late-gestation cows and heifers can reduce harm from dystocia when a malformed calf is present. Prompt intervention helps protect the dam and may lower the risk of severe postpartum complications.

The most effective prevention plan is herd-specific. Work with your vet to connect the calf's findings, breeding records, geography, and diagnostic results into a practical next-step plan for future pregnancies.