Gene Test, Research Unravel Severe Skeletal Atavism Limb Deformity in Shetland Ponies

Limbs of a 16-week old Shetland pony with Skeletal Atavism, often described as "bow legs". (Left) caudal view when standing; (center) caudal view when walking and (right) view from the front when standing square.  Complete, or "fused", fibulas and ulnas cause instability in the tarsocrural and antebrachiocarpal joints respectively; the angular limb deformity becomes more severe at the walk. Photo: Ove Wattle

Skeletal Atavism is a genetic defect that can cause skeletal deformities in Shetland ponies. The deformity has now been genetically identified by researchers at Uppsala University and the Swedish University of Agricultural Sciences (SLU), in cooperation with colleagues in the USA at Texas A&M University, the University of Kentucky's Gluck Center, and the University of Washington, as well as at the University of Qatar in the Middle East. The discovery means that healthy carriers now can be identified for better breeding decisions with the use of a gene test.

Polydactyl Horses (and People): Why Are Some Horses Born with an Extra Hoof?

This polydactyl was found in British Columbia by one of the farrier students at Kwantlen College. Gerard Laverty, the instructor at Kwantlen, sent these images to me, which started my collection. Image © Hoofcare Publishing and Gerard Laverty.

If you visit farms and horse barns in New England, you'll sooner or later find one with a clan of double-pawed cats. Their owners are usually quite proud of them and love to show off their big mitts. The condition is so common around here that most people don't give it a second thought. A lot of people actually prefer them, especially if they are Maine Coon Cats.

But when the equivalent of a "double paw" shows up on a giant Shire draft horse, people notice.