Hoof Wall Separation Disease (HWSD)
Hoof Wall Separation Disease or HWSD is a condition that has been identified in Connemara ponies and horses that have been crossed with Connemara ponies. HWSD is an autosomal recessive genetic disorder that affects the coronary band causing cracks to form. All four feet will be affected by the disease. Damage can be seen in affected ponies as young 2-3 weeks of age. In rare cases some affected ponies develop less severe form of the disease. This is due to the fact that the mutation is not fully penetrant. In very few case the disease can be managed but in other case the ponies must be euthanized. Studies estimate that in the general population the percent of horses carrying a single copy of the disorder is around 15%.
Unfortunately, there is no cure of HWSD. As the condition worsens, the foal will begin to develop severe infections, as well as suffer from increasing pain and discomfort.
HWSD is a recessive trait, meaning a foal can only be affected if the foal inherits the disease from both parents. Parents that are carriers do not have any symptoms associated with HWSD. However, they will pass on a copy of the defective gene to their offspring 50% of the time. If breeding two carriers the foal has a 25% chance of being affected and a 50% chance of being a carrier.
Testing for Hoof Wall Separation Disease in Connemara ponies and horses that have been crossed with Connemara ponies.
Animal Genetics UK offers DNA testing for Hoof Wall Separation Disease (HWSD). The genetic test verifies the presence of the dominant HWD mutation and presents results as one of the following:
|HD/HD||Affected||The horse carries two copies of the HWSD mutation and is homozygous for HWSD. The horse is affected with the HWSD genetic disorder associated with your breed.|
|n/HD||Carrier||Both the normal and mutant alleles were detected. Horse tested heterozygous for HWSD and is a carrier of the HWSD mutation associated with your breed.|
|n/n||Clear||Horse tested negative for HWSD and does not carry the HWSD gene mutation. The horse will not pass on the defective gene to its offspring.|