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Saturday, 27 September 2008

Devon Rex cat breeding

Devon Rex cat kitten
Devon Rex kitten - Tilba - aged 13 weeks
Photo by petrichor
His health has no connection to this post.

Current Devon Rex cat breeding is or perhaps should be focused to at least a certain degree on hybridization and outcrossing to entirely different breeds when bearing in mind the history of the Devon Rex cat.

This cat breed started life from a single discovered cat, Kirlee in 1959 (see Devon Rex cat). That automatically meant a very small gene pool from which to breed. The gene pool remained small. Because the gene that makes the Devon Rex what he/she is (the curly coat) is recessive the gene pool was expanded by inbreeding at the early stages.

Inbreeding can (will?) eventually cause genetic problems (genetic diseases) and this was and is the case with the Devon Rex cat. This breed has a larger than normal number of genetic diseases (see Genetic Diseases in Purebred Cats for a comparison). A notable and distressing genetic disease is Spasticity, which prevents swallowing.

As I understand it Richard Malik of the University of Sydney who did work on this believes that the Spasticity that rarely occurs in the Devon Rex is a form of muscular dystrophy. The kittens die when choking on food - most distressing. The signs and symptoms include:
  • head sinking to chest when in the litter box
  • slow use of litter box
  • bobbing head
  • gait has a high step
  • chin rests on chest
  • biting is painful
  • enlarged esophagus that traps swallowed food

Devon Rex cat breeding includes outcrosses to the British Shorthair and American Shorthair under CFA rules. Other outcrosses have been used in the past. As mentioned the gene that produces the curly coat (signified by the symbol re) will only produce curly coats in second generation outcrossed kittens and then only 50% will be curly. This is not useful economically to a breeder and is a barrier to hybridization. It is the classic commerce -v- health argument for breeders.

In addition to the above genetic disease a blood type problem has been encountered. When a male with type A blood in mated with a female with type B blood the mother creates antibodies that can kill her kittens. Under these circumstances the breeder hand feeds the kittens until the kitten gets used to the antibodies. This would seem to prevent the death of the kitten. Blood typing is carried out to avoid the problem happening in Devon Rex cat breeding.

Breeders are doing all they can I understand to resolve these matters in their Devon Rex cat breeding programs.

From Devon Rex cat breeding to home page

Devon Rex cat breeding - Source of info on Spasticity: www.pandecats.com - source of blood type disease: CFA.

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