This breeding season we have had a lot of responsible breeders testing for Fragile Foal Syndrome (aka Warmblood Fragile Foal Syndrome or WFFS). Well done to those breeders.
The horses we have tested are mostly Warmbloods and related breeds, but we have also tested some Thoroughbreds and Australian Stock Horses.
The overall carrier rate for Fragile Foal Syndrome for horses we have tested is over 11%. This carrier rate is higher than our initial estimate of 7-8%.
Our testing has identified a couple of Australian Thoroughbreds as carriers for Fragile Foal Syndrome. Fortunately Fragile Foal Syndrome does not seem to be as common in Thoroughbreds as it is in Warmbloods.
At this point almost all breeders who choose to test don’t know which of their horses may be carriers. This means that the carrier rate we have seen is likely to be similar to the overall carrier rate in the general population, because we are not being sent biased samples (yet!). In future years we will see more positives as owners test foals produced by carriers. These foals have a 50% chance of being carriers like their parents.
Click here to order a test for your horse http://practicalhorsegenetics.com.au/index.php?dis=wff
We encourage breeders to test their horses and avoid breeding carrier to carrier. When a carrier is bred to a carrier there is a 1 in 4 chance of an affected foal. There are no known examples of foals with Fragile Foal Syndrome surviving to adulthood. For more information about Fragile Foal Syndrome see our archives https://horse.practicalhorsegenetics.com.au/wpr/2018/09/18/fragile-foal-wffs-or-ffs-update/