Breeding Policy for the Devon Rex
This document is seen as a way of ensuring breeders observe what is considered 'best practice' in their involvement with Devon Rex and particularly in their Devon Rex breeding programmes.
Devon Rex, unlike most breeds, owe their origin to one cat - Kirlee. It should always be remembered that most of the females bred to Kirlee were very closely related as well as being immediate descendants of Kallibunker - the original Cornish Rex, as at that time it was assumed Kirlee resulted from the same mutation as Kallibunker.
Inbreeding was then carried out in the ensuing generations to produce the three generations of Rex to Rex breeding needed to obtain breed recognition. This practice of inbreeding has continued. From the beginning, serious health problems have beset Devon Rex, i.e. Luxating Patellae, Coagulopathy and Inherited Myopathy (Spasticity), now known as CMS.
Two blood types have been confirmed in Devon Rex - type A and type B. Type A is dominant over type B. This means that a cat with type B blood is homozygous for B. Type A cats can either be homozygous for A or heterozygous (carrying the B gene). Cats with type B blood have strong antibodies against type A red blood cells. These anti-A antibodies can cause two serious problems : Neonatal Isoerythrolysis (Fading kitten syndrome) and transfusion reactions.
It is vital regular selective out-crossing be introduced and maintained to increase the gene pool and improve stamina and health. This is 'best for the breed' in its ongoing development.
Devon Rex are not compatible with Cornish Rex, Selkirk Rex or LaPerms. Such matings are therefore highly undesirable. The product of such matings will be registered on the Reference Register and cannot be considered to be variants.
They cannot be used in ANY GCCF Rex breeding programme and should be placed on the non-active register. It is considered to be in the best interest of the Devon Rex breed to keep it entirely separate from other incompatible Rex mutations.
Under no circumstances should any cat with Sphynx ancestry be introduced into the Devon Rex breed. Selection for hairlessness contradicts the coat quality requirements for Rex cats. The product of any matings between Sphynx and Devon Rex will be registered on the Reference Register. They cannot be considered to be variants nor be used in any Devon Rex breeding programme and should be placed on the non-active register.
Breeders are recommended to DNA test their breeding cats for the known Longhair genes. Longhair Devon Rex or Devon Rex variants with Longhair may be used for breeding but should be mated to cats which do not carry one of the Longhair genes. The long-hair gene/s has been present in the breed since the beginning, as Kirlee was a proven Longhair carrier. Outcrosses made to breeds with Longhair ancestry should be undertaken with caution and where possible only to cats proven by DNA test not to be carriers of the long-hair gene/s.
Breeders shall ensure that any Devon Rex or Devon Rex Variants from which they breed, shall be registered with the GCCF in accordance with the Rules in force at the time.
Breeders and owners of Devon Rex and Devon Rex Variants are recommended to blood type test all their cats but more especially all breeding animals. Blood type A kittens resulting from a mating between a type A stud and a type B queen may die within the first few days of life if allowed to suckle their mother's colostrum.
It is also important to know that cats with the relatively rare type B blood can die if given a transfusion of the common type A blood.
All cats used for out-crossing should be thoroughly researched, of sound temperament and free from any hereditary defects.
Breeders should ensure, to the best of their knowledge, that any Devon Rex or Devon Rex Variants from which they breed are of sound temperament, free from any hereditary defects, (including those listed in the GCCF Standard of Points), and conform as closely as possible to the Standard of Points (excluding the coat description where variants are concerned).
It is recommended that the progeny from any matings that are not required for Devon Rex breeding, should be placed on the Non-Active Register, to avoid the introduction of the Devon Rex gene into other varieties of pedigree cats.
The majority of matings are most likely to be between Devon Rex x Devon Rex and Devon Rex x Devon Rex Variant, but to ensure maximum benefit from outcrossing Devon Rex Variant x Devon Rex Variant matings are also necessary.
Normal coated progeny from Variant x Variant matings cannot be considered variants unless DNA tested to be carrying the DRX gene.
Breeds which have been approved for use in outcrossing are: Abyssinian, Asian Shorthair, British Shorthair, Burmese, Korat.
All other breeds are listed as non-approved.
Breeders will be encouraged to take advantage of any relevant official scheme, which may be devised by the Joint Rex BAC to test the soundness of the Devon Rex breed.
Note: Devon Rex and Devon Rex Variants may be registered on the Active Register only if they have themselves been genetically tested as normal for the CMS gene, or their parents have been tested normal, or cats on every pedigree line in previous generations have tested normal.
Note: It is recommended where the colour of a cat is in question a DNA test, (where such a test exists), be arranged.