The symptoms are characterized by severe lesions and scarring along the animals back typically at the age of two or generally when the horse is being broke to the saddle. There is no cure for the condition and horses with the disease are euthanized because they are unable to be ridden and, of course, are not suitable for breeding. Breeding with an infected horse have at lease a 25% chance of producing an infected foal.

Because other skin conditions can mimic the symptoms of HERDA, a DNA test for HERDA has been developed by genetics researchers at Cornell University and is now available to the public. . An additional DNA test is also available from UC Davis that aids the veterinarian in diagnosis. Breeding of carrier horses have a 25% chance of producing an infected animal. Mating between normal and carrier horses will not produce a HERDA foal although 50% of the foals may be carriers.

Dr Ann Rashmir-Raven at the University of Michigan State University’s Animal Husbandry Research department have traced possible carriers back as far as the famous “POCO BUENO.” There are probably some other famous stallions that may have been the initial carriers.

(Dr Ann Rashmir-Raven, DVM, may be reached at Michigan State’s Clinical Sciences, Office of the Dean @ 517-355-1886. Her address is College of Veterinary Medicine, G209 Veterinary Medical Complex, East Lansing, MI 48824-1314. Dr Raven-Rashmir would be a wealth of the latest information plus she’s a delight to talk to!)