30 June 2000

Crooked joint infirmity hereditary

ARTHROGRYPOSIS, a congenital malformation which cause animals to have crooked joints, is an inherited deformity, according to a study at University College Dublin.

When 58% of lambs were born with malformation of the fore limbs in a Suffolk flock, Michael Doherty and colleagues tested the ram to discover if the condition was inherited.

These malformations are usually rare and can be associated with intrauterine or viral infections, but it has been reported as an inherited condition in Australian Merino sheep, according to their report in the Vet Record.

Using embryo transfer, the researchers bred from the ram, two ewes that had produced malformed lambs and four daughters of the test ram born with abnormal forelimbs. Of the 12 live lambs born from these ewes embryos, 10 were affected by the deformity.

The data collected from this and a control study using unrelated ewes sired by the affected ram, which all had normal lambs, shows that the condition is inherited as the result of a recessive gene.

Researchers conclude the ram and a high proportion of ewes in the flock carried the arthrogryposis gene.