Warmblood Foal Disease Spreads To USA

Foals born with WFFS are unlikely to ever get into a paddock
Credit : Lulu Kyriacou

Friday 25 May - 02h21 | Stephanie Sieckmann & Lulu Kyriacou

Warmblood Foal Disease Spreads To USA

Warmblood Fragile Foal Syndrome (WFFS) has quickly become a hot topic in the US this spring after a stallion keeper in  the US-American Hanoverian Association announced publicly that one of his stallions had been identified as a carrier of the gene. The genetic disorder is fatal to new born foals who carry it, and appears to be on the increase.

First seen in 2014, an affected WFFS foal is born with a two copies of the mutated LHl gene, one coming from each parent. The affected foal will display extreme skin fragility characterised by tearing and ulceration from contact with normal surroundings. Small skin lesions can occur anywhere on the body, but are most noted on pressure points such as the joints.. In addition to skin wounds, lesions may also be found on the gums and other oral cavity mucous membranes. The limb joints are lax and hyperextensible. Fetlocks are the most dramatically affected generally preventing a foal from standing normally. Unfortunately there is no cure and all affected foals must be euthanized soon after birth on humane grounds.

​The disorder is completely preventable if parents are tested for being carriers of the defect and are not mated with another carrier. A similar issue used to affect the British Fell Pony  but has been almost eradicated through selective breeding.  A foal produced by the mating of two carriers has a 25% chance of being born affected and 50% of being a carrier even if showing no outward signs.

Dr Richard Newton of the Animal Health Trust said: “As Warmblood Fragile Foal Syndrome has a simple recessive mode of inheritance, DNA testing both potential parents prior to breeding will quickly, and easily, identify carriers of the mutation. This should reduce the incidence of the disease quite quickly as affected foals are only produced when two carriers of the genetic mutation are mated. Over the longer term, use of the DNA test could eventually eradicate Warmblood Fragile Foal Syndrome without adversely affecting the breed, as carriers can still be bred with, as long as they are bred to a genetically clear horse. The Animal Health Trust developed a DNA test for Fell Pony Syndrome in 2009 and with effective use of the DNA test, this disease appears to be under control in Fell ponies.”


Several European studs have announced that they will also be testing their breeding stock. The Glock Horse Performance Center in Austria  announced on their social media pages that,  \"The stallions of Gaston Glock have been examined for the genetic defect WFFS. Now the results are available, as the Center announces on its Facebook page. Romanov as well as Zonik, Voice, Toto Jr. and Johnson are not carriers and therefore can be easily used for all mares. The situation is different with Total U.S. The test has shown that this son of Totilas  from a Sir Donnerhall I mare carries the gene. Therefore, only mares may be matched with him for which evidence can be provided certifying that the mare is not a WFFS bearer.\" 

The Dutch Warmblood Breeding Society (KWPN) has stated it will start mandatory testing in it's approved sstallions but as yet there is no official advice in the UK but Sports Horse Great Britain said that they will be discussing the situation in a meeting in June.  

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