Foal Immunodeficiency Syndrome

First identified in Fell Ponies, and later in Dales. 

The syndrome is an inherited disease (it cannot be caught, foals are born with it).  If a syndrome foal is born, BOTH its parents MUST be carriers, as the faulty gene is recessive –(it takes two carriers mated together to produce the condition).  The foals affected have a defective immune system and cannot resist disease properly – they die, usually within the first month or two of life, of problems including pneumonia, scouring and anaemia.  The condition is invariably fatal if usual treatments are employed. Not every foal of two carrier parents are born with the syndrome – the chance of a syndrome foal from each mating of two carrier ponies is 1 in 4.  However, other unaffected foals may well be carriers.

Carriers are ponies that carry the faulty gene, and when crossed with another carrier, produce the 1:4 chance of a syndrome foal. Crossing a carrier with an unaffected pony will give a 50:50 chance of the foal being a carrier of the gene, although it will not be affected with syndrome.

Thanks to the wonderful work from the team at Liverpool Veterinary Hospital there is now a test to identify carriers and therefore affected foals are not seen in the Dales Pony. 

All colts now must be tested Clear to be eligible for licensing and have been since 2012. Mares, however, may be carriers and the only way to know is by testing which can be done through the society which holds hair samples for all registered ponies – please contact the Secretary

The current cost of a FIS test is £55. 


Does my pony have FIS?
If your pony is older than 3 months of age then NO, It will not develop signs of FIS, although it could be a carrier

I want to buy a weanling, could it have the syndrome?

If it is old enough to be weaned then NO, although again it could be a carrier.

What is a carrier?

A carrier is a pony who is outwardly normal and healthy but whose DNA contains the gene for FIS. If a carrier mare and a carrier stallion are bred then there is a 1 in 4 chance of breeding an affected foal.

How many ponies could be carriers?

Unfortunately we just don’t know. It has been suggested in Dales to be 12-15% although this has not been proven.

I want to breed from my pony, could he/she be a carrier?

Unfortunately the only answer to this is possibly yes. If they have previously bred a foal with FIS then the pony IS a carrier.

I want to breed from my pony, how can I tell if the stallion or my mare is a carrier?

Ask the stallion owner to see a Certificate to see if he is FIS Clear, if the certificate can’t be produced assume he is a carrier and only use him on a Clear mare. Your mare can be tested; contact the Secretary for details.

Should I avoid breeding from my Carrier pony?

No, but you must ensure that any stallion you use is clear to avoid breeding an fatally affected foal. Breeding from a carrier and a clear pony will give you a 50% chance of breeding another carrier and also 50 % chance of breeding a clear pony. The Dales Pony Society will not license carrier colts but a clear colt or a clear filly will continue your bloodline and be your future breeding prospect.