What do you think when you hear that the Thoroughbred has a narrow gene pool? Perhaps you are as skeptical as I was. I was skeptical because of my two decades’ involvement with rare breeds of livestock where we think about the size of gene pools often. But Deb Bennett makes a convincing case in the most recent of her series of articles on the history of the Thoroughbred in Equus magazine. Of particular interest in this recent article is her discussion of the impacts of breeding winners to winners on characteristics of the breed. Fell Ponies provide a notable contrast so far.
Bennett has laid out how the Thoroughbred gene pool has been narrowed by selection towards horses that can sprint. She has also documented how race distances have decreased since the establishment of the breed. By selecting for sprinters, Bennett suggests that other characteristics that have historically been important in the breed, including stamina, balanced conformation, disease resistance, and soundness, have been lost. (1)
In the Spring 2014 newsletter of The Fell Pony Society, David Murray states, “The Rare Breeds Survival Trust believes that the Fell pony has suffered no such genetic erosion during the last century.” (2) Murray is referencing studies that have shown that the Fell Pony gene pool is indeed healthy compared to other breeds, including the Exmoor. (3) The context for Murray’s comment is the topic of conservation grazing where Exmoor ponies are sometimes chosen instead of the Fell.
In his discussion Murray points out that while Exmoors were naturally selected for survival in harsh environments, the current breed is “the product of circa only 50 individuals.” (4) In contrast, while Fell Ponies have in theory, based on the stud books, been similarly genetically limited in the past, DNA research has shown that Fells have “comparatively high genetic and phenotypic diversity” that may mean Fells have “retained more genetic grazing characteristics required for successful adaptation to climate and land changes…” (5)
The most recent Conservation Priority List from The Livestock Conservancy has moved the Dales Pony to Critical status. “The closely related Fell Pony is more popular and remains in the Watch category.” (6) The Fell was moved to Watch status in 2010. It is of course a testament to the hardiness of Fell Pony stewards that the breed’s conservation status has improved.
However, as the situation with the Thoroughbred demonstrates, any breed can lose genetic diversity. With regard to the Fell Pony, in the North American population, currently 23% are related to a single, still-living, imported stallion. (7) Bennett states that live cover requirements have kept the narrowing of the Thoroughbred gene pool from being worse than it is. Her point is well taken: artificial insemination (AI) is allowed in Fell Ponies, and some progeny of that imported stallion that is related to so many ponies here were conceived via AI. Hopefully Fell Pony stewards will refrain from over-using particular stallions so that our gene pool remains diverse and all breed characteristics are retained.
- Bennett, Deb, PhD. “The Thoroughbred Gene Pool,” Equus #452, May 2015, p. 81.
- Murray, David. “Letter to the editor,” The Fell Pony Society Newsletter Spring 2014 Volume 28, Appleby, Cumbria: The Fell Pony Society, p.12.
- See for instance the discussion in Morrissey, Jenifer. “Fell Pony Genetic Diversity 3,” Fell Ponies: Observations on the Breed, the Breed Standard, and Breeding, Walden, Colorado, Willowtrail Farm, 2013, p. 99.
- Same as #2.
- Same as #2.
- The Livestock Conservancy. “2015 Conservation Prioity List Released,” The Livestock Conservancy News, Winter 2015, Volume 32, Issue 1, p. 1.
- Morrissey, Jenifer. “Stallion Genetic Concentration in North America,” Fell Pony News from Willowtrail Farm, January 2015.
© Jenifer Morrissey, 2015
If you like articles like this one, you’ll also like the book Fell Ponies: Observations on the Breed, the Breed Standard, and Breeding, available internationally by clicking here.