New stallions entering the Westfalen Warmblood books are now required to have WFFS (Warmblood Fragile Foal Syndrome) test results on file, along with the standard DNA Parentage Verification. German Riding Pony stallions must now have DNA test results on file for CA (Cerebellar Abiotrophy), as well as Myotania if descending from any New Forest Pony lines. Carrier result status will not affect registration eligibility and will be recorded in the German VIT database.
Horse breeding does not only mean looking at the genetic abnormalities of a horse. There are many other factors that play a role in horse breeding and help to achieve the breeding goals. Incidentally, one should look at hereditary defects, but the stallion choice should not be based on it. It is not good to discriminate stallions only based on their WFFS status. WFFS is not the only gene defect that we know of. If you want to exclude all stallions with the various gene defects, then there will be no breeding stallions at any given moment. At present, the population with WFFS carriers is ten percent. We do not know whether this has been the percentage for some time, or whether this value increases exponentially. Fortunately, ten percent is still small enough that having public status is sufficient. Due to the mandatory specification of stallions and the breeders who have their mares tested, we are getting more results and we can observe how the genetic defect spreads in the future, and in case of necessity make a plan to influence it later.
A topic in the news causing significant concern among breeders for the past 18 months, Warmblood Fragile Foal Syndrome (WFFS) is a genetic disorder which can affect warmbloods whose parents are carriers of the recessive gene. Carriers themselves are not affected, but can pass the defective gene on to their offspring. Foals receiving a copy of the gene from both parents are affected by extremely fragile skin and connective tissue and cannot survive.
Westfalen NA offers the WFFS, CA and Myotonia DNA tests either as a stand-alone test or in combination with parentage verification through our partnership with UC Davis Veterinary Genetics Lab. Horses with DNA samples already on file may have a carrier test done on existing hairs already at the lab. The cost is $35 for these additional tests.
Cerebellar abiotrophy is a degenerative disease affecting the cerebellum, the portion of the horse’s brain responsible for basic balance and coordination. Just like the WFFS condition, CA is Autosomal Recessive transmission – meaning both parents must be carriers in order to produce an affected foal. Cerebellar abiotrophy most frequently affects foals one to six months old . Symptoms progressively worsen in most cases and include loss of balance, head shaking and tremors, disorientation and affected gait. This condition is generally associated with purebred Arab horses or those that have Arab blood, which includes the German Riding Pony population.
Just as DNA record-keeping in breeds such as New Forest Ponies has helped control the risk of producing foals affected by Myotonia, so will identification of carriers of WFFS help breeders make educated breeding decisions, as more is learned about this disease. Learn More about WFFS