MADAM,

I WOULD like to raise a number of concerns about the article “Warmblood Fragile Foal Syndrome – a dilemma for breeders and sport?”, by Anne Hughes.

1. When this disease was first diagnosed, and the molecular basis of this defect was identified by my friend Dr. Nena Winand of Cornell University, the word “warmblood” was included in its name because early research found the mutated allele in warmblood horses. We now know that the mutation is found in a variety of breeds, some of which have no warmblood genetics including Thoroughbred. Therefore while the abbreviation “WFFS1” is commonly used and should continue to be used, WSI has dropped the word “warmblood” from the name of the syndrome and we refer to it simply as “Fragile Foal Syndrome”.

2. Proclaiming the source of the mutation to be a Holsteiner horse -- and a specific Holsteiner horse -- is neither logical nor scientific. As mentioned above, the mutated allele has been found in non-warmblood breeds including Thoroughbred. To the best of my knowledge, Holsteiner horses have not been used in Thoroughbred breeding; therefore it is impossible for the source of the mutation to be a Holsteiner (or to be solely a Holsteiner). It is much more likely that the source is a Thoroughbred or Arabian horse that was used, or whose descendants were used, in warmblood and other breeding. And this means that Thoroughbreds, Traditional Irish Sport Horses, Connemara Ponies, and other Irish breeds or types with Thoroughbred genetics also are at risk.

3. Dr. Hughes very briefly mentions WSI’s testing programme but mischaracterises its scope. Readers should be aware that to date 81 (hardly a “small number”) Approved Stallions, Approved Mares, Studbook Mares, and foals have been tested, and testing continues on a weekly basis. All horses have been declared non-carriers of WFFS1. WSI was the second studbook in the world to announce a testing program, the third to announce a mandatory testing program, and the first to announce a mandatory testing regime for all actively breeding horses in the population, and their foals. Our mandatory testing regime for stallions, breeding mares, and foals was approved by our membership in a referendum with 100% support, and has been approved by DAFM. WSI’s testing regime is the most comprehensive in the world.

4. Dr. Hughes reports that few jumping stallion have been tested, and this simply is not accurate. WSI, KWPN, NRPS, and Westfalen studbooks, and an increasing number of other studbooks and stud farms on the continent, in North America, and in Australia, have tested active approved stallions; to my knowledge 19 showjumping stallions have tested as carriers.

5. For Dr. Hughes to single out untested stallions such as Cavalier Royale, Luidam, and Big Star is uncalled for. Call out the owners for not testing or for not disclosing test results; that is fair. But to call out stallions because of inferences made from an uninformative pedigree analysis is unfair.

6. Dr. Hughes’ statement that certain “WFFS carriers appear to be a special bunch” with respect to elasticity is making an inference from a handful of horses. This is unscientific: the hypothesis that there is a relationship between being a carrier and having overly elastic connective tissue is simply that – a hypothesis. To date this issue has not been studied and to make any policy recommendations on the basis of speculation is ill advised and dangerous. Therefore it is unreasonable to call for a ban of carriers from high-level sport on the basis of conjecture. While WFFS1 is a serious issue for sport horse breeding it is not, and most likely never will be, an issue for sport.

7. Finally, all studbooks that have Thoroughbred genetics in their population should join WSI in implementing a testing program, and this is the policy recommendation that Dr. Hughes should have made. For Dr. Hughes to state that it is “inevitable that there are numerous carriers of WFFS competing and breeding in Ireland” because of the presence of KWPN and Holsteiner in the ISH population is off target: the most likely source, as mentioned above, of the mutated allele is Thoroughbred or Arabian blood, which was introduced into the ISH population decades before the first warmblood stallion or mare was imported into Ireland. Every population with Thoroughbred genetics needs to test, not every population with warmblood genetics.

At a minimum all stallions must be tested, and test results must be disclosed to breeders. Studbooks are invited to join WSI in breeder education initiatives that call on mare owners to test their mares and to ensure that they do not use carrier stallions with their carrier mares. Some mare owners may decide to cull their carrier mares but that choice is up to them. WSI’s advice to breeders is: Do not use a stallion unless the stallion’s WFFS1 status has been disclosed, and you know the status of your mare. To date, the only stallions in Ireland whose status has been disclosed are WSI Approved Stallions. Hopefully 12 months from now, that statement will be incorrect.

Yours etc,

Thomas Reed, Ph.D.

Breeding Director

Warmblood Studbook of Ireland

Scarriff, Co Clare