Lavender foal syndrome or LFS is a newly classified genetic condition that exists in the Arabian horse breed. It is caused by an autosomal recessive gene, which means that it is directly inherited from each of the parents. Both the sire and dam must have the recessive gene for LFS and must pass it to the foal in order for the foal to have the defect. A horse, either male or female, that has only one copy of the gene for LFS will not exhibit any signs or problems throughout their life, it will only be their foal, if they are crossed with another LFS recessive horse that will have the risk of being born with the syndrome.
The most telling diagnosis of LFS is the unique color of the foal. He or she will be born with a lavender, silver or pinkish tinge to the coat that is different from a gray or roan coloration, it is very abnormal in color. The eyes may also be somewhat bluish to gray in color, but this is often not as noticeable. The mare will usually have troubles during the delivery of the foal and the foal will be unable to stand or move his or her legs. The difficult delivery is due to the rigidity of the foal that often includes having the head and neck arched backward.
Once born the foal will have muscle spasms and be unable to get to his or her feet. Often they will struggle but seem unable to coordinate their movements. They will suckle if bottle fed but usually die within one to three days of birth. While alive the foal will have rapid, abnormal eye movements and may also have respiratory problems. Researches that have autopsied these foals have found that there are lesions on the brain that affect the functioning of the central nervous system. There appears to be no sex-linked genetic component to the rare condition as both male and female foals have been diagnosed with the fatal syndrome.
In more recent studies it is noted that some of the light colored Arabian foals are more prone to epilepsy and other seizure disorders, so researchers are working to discover if both these conditions may be related, with foals with LFS being the more severe expression of the genetic component.
Breeding a mare and stallion that has produced a LSF foal means that there is a two in four chance that any offspring from the mating will have the LSF gene in their makeup. Many breeder voluntarily pull any mares or stallions that produce a LFS foal out of breeding programs, but others are not as responsible so the gene is likely to continue on in the breed. Since a clear horse can breed with a recessive horse with no problem, they are not worried about the condition occurring. The problem could, however, occur should that offspring ever be bred to another recessive LFS carrier.
More research in to trying to identify and test for the genetic marker that causes LFS will be needed in the future to try to establish guidelines for Arabian breeders.
|
