Answer» What is Foal Immunodeficiency Syndrome mean?
Foal immunodeficiency syndrome (FIS), originally known as Fell pony syndrome, mainly affects two breeds of ponies: the Fell and Dales. FIS is a recessive genetic disease. Affected foals appear normal at birth, but become weak, and either die or are euthanized by three months of age due to persistent infections caused by immunodeficiency.