Equine Science Update
Reports from the world of equine research.
Fell ponies are not the only breed to be affected with an immunodeficiency / anemia syndrome. Now a similar condition has been reported in a Dales pony
Fell Pony Syndrome is a fatal condition that affects the immune system of young foals.
Affected animals are unable to respond adequately to infection. Signs usually appear first when the foal is a few weeks old. They include loss of condition, diarrhea, coughing and weight loss. As the condition progresses, the foal develops anemia, immune dysfunction, and wasting. Foals die, usually before they reach three months of age, from infectious diseases that they cannot overcome.
The condition is not only found in the Britain. Affected Fell pony foals have been reported in the Netherlands and the USA. However, until recently the syndrome had not been identified in other breeds of pony.
A report in the Veterinary Record describes a case in a Dales pony that showed characteristic signs of “Fell pony syndrome”.
The report’s authors, based at the Animal Health Trust in Newmarket and the Liverpool Veterinary School, describe a female Dales pony foal with marked anemia, diarrhea and pneumonia, that failed to respond to treatment. The foal was euthanased at nearly 6 weeks of age. Post mortem signs were typical of Fell pony syndrome.
In Fell ponies, analysis of the pedigrees of affected foals strongly suggests that the condition is caused by a single autosomal recessive genetic defect. This means that foals are only affected if they inherit a defective gene from both parents.
It is not known how many animals are carriers. Research, funded by The Horse Trust, aims to develop a test to identify carrier animals. Until that is available, a “best guess” based on the number of affected foals, suggests that probably between 60 -90% of the breed carry the defective gene.
Although the Dales and Fell ponies are closely related, the report’s authors suggest that it is unlikely that the disease has been present in the Dales pony going back many years. No cases have been identified previously in the breed, despite close monitoring by the breed society.
They explain that all cases in the Fell pony can be traced back to a common ancestor in the 1950s. It is more likely that the defective gene passed to the Dales pony by cross-breeding with the Fell pony after that date.
The scientists, who are already studying Fell pony syndrome, are now widening their scope to pay close attention to the Dales pony as well.
They suggest that, although there are other causes of anemia in foals, the anemia/immunodeficiency syndrome should be considered in any young foal with marked anemia (PCV < 20%) and relevant clinical signs.
They urge owners, breeders and veterinarians dealing with Dales ponies to be aware of the disease, and ask that any suspect cases be referred to the research team at the Animal Health Trust or the Liverpool University Veterinary School.
For more details see:
Immunodeficiency / anaemia syndrome in a Dales pony.
L Fox-Clipsham, JE Swinburne, RI Papoula-Pereira, AS Blunden, F Malalana, DC Knottenbelt, SD Carter.
Veterinary Record (2009) 165, 289 -290.
Fell Pony Syndrome is a fatal condition that affects the immune system of young foals.
Affected animals are unable to respond adequately to infection. Signs usually appear first when the foal is a few weeks old. They include loss of condition, diarrhea, coughing and weight loss. As the condition progresses, the foal develops anemia, immune dysfunction, and wasting. Foals die, usually before they reach three months of age, from infectious diseases that they cannot overcome.
The condition is not only found in the Britain. Affected Fell pony foals have been reported in the Netherlands and the USA. However, until recently the syndrome had not been identified in other breeds of pony.
A report in the Veterinary Record describes a case in a Dales pony that showed characteristic signs of “Fell pony syndrome”.
The report’s authors, based at the Animal Health Trust in Newmarket and the Liverpool Veterinary School, describe a female Dales pony foal with marked anemia, diarrhea and pneumonia, that failed to respond to treatment. The foal was euthanased at nearly 6 weeks of age. Post mortem signs were typical of Fell pony syndrome.
In Fell ponies, analysis of the pedigrees of affected foals strongly suggests that the condition is caused by a single autosomal recessive genetic defect. This means that foals are only affected if they inherit a defective gene from both parents.
It is not known how many animals are carriers. Research, funded by The Horse Trust, aims to develop a test to identify carrier animals. Until that is available, a “best guess” based on the number of affected foals, suggests that probably between 60 -
Although the Dales and Fell ponies are closely related, the report’s authors suggest that it is unlikely that the disease has been present in the Dales pony going back many years. No cases have been identified previously in the breed, despite close monitoring by the breed society.
They explain that all cases in the Fell pony can be traced back to a common ancestor in the 1950s. It is more likely that the defective gene passed to the Dales pony by cross-
The scientists, who are already studying Fell pony syndrome, are now widening their scope to pay close attention to the Dales pony as well.
They suggest that, although there are other causes of anemia in foals, the anemia/immunodeficiency syndrome should be considered in any young foal with marked anemia (PCV < 20%) and relevant clinical signs.
They urge owners, breeders and veterinarians dealing with Dales ponies to be aware of the disease, and ask that any suspect cases be referred to the research team at the Animal Health Trust or the Liverpool University Veterinary School.
For more details see:
Immunodeficiency / anaemia syndrome in a Dales pony.
L Fox-
Written by Mark Andrews. Published online 14.11.09.
© Copyright Equine Science Update 2009
© Copyright Equine Science Update 2009
Immunodeficiency/anemia
in Dales pony
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