What is Connemara Pony Hoof Wall Separation Disease or HWSD?
The following information comes from the UC Davis Veterinary Genetics Laboratory
"Hoof Wall Separation Disease (HWSD) is a genetic defect characterized by a hoof wall that easily breaks and cracks, and a normal appearing coronary band. The breaks and cracks begin to occur in young ponies. In severe cases the pony bears weight entirely on the sole of the foot which can lead to severe lameness. HWSD is inherited as an autosomal recessive trait. This means that carriers are completely normal and only animals with two copies of the mutation will show clinical signs of the disease. HWSD appears to occur only in the Connemara pony and the carrier frequency has been estimated to be about 14.8%. A DNA test for this specific mutation can determine if ponies are normal or if they carry one or two copies of the mutation. Ponies that carry two copies of the mutation are highly likely to be affected with
"the disease. Some cases are milder while others are more severe. We have identified at least one case where the pony does not appear to have clinical signs associated with having two copies of the mutation. This indicates that the mutation is not fully penetrant; however it has very high penetrance of 96.8%.
"The VGL offers a DNA test for HWSD to assist owners and breeders in identifying affected and carrier ponies. The test uses DNA collected from mane hair thus avoiding invasive blood collection. Breeders can use results from the test as a tool for selection of mating pairs to avoid producing affected foals."
To learn more about HWSD, visit these Web sites: UC Davis VGL and the Connemara Pony Research Group
*Smaragaid Cliff tested N/N for HWSD, which means that he is normal and does not carry the gene for the disease. His test results are on file with both the American Connemara Pony Society and the Connemara Pony Research Group.
Cliff will breed QUALITY purebred Connemara mares that are HWSD carriers and HWSD affected. Why?
The answer comes from the Connemara Pony Research Group in its April 15, 2015, blog:
"If genetic diversity is not encouraged in the here and now, then the future for the breed is grim and increasingly at risk. Exclusion of carrier ponies and affected females from the breeding herd will spell doomsday."
A note to breeders with part-bred Connemara mares: Research and testing shows that part Connemaras also can carry the HWSD gene, so your best choice is to test before breeding to a Connemara (purebred or part bred) stallion. If you choose not to test your mare, make sure you choose a stallion that is not an HWSD carrier.
". . . I the LORD have spoken, and I will do it. . . And so I will show my greatness and my holiness, and I will make myself known in the sight of many nations. Then they will know that I am the LORD." Ezekiel 36:36; 38:23