1. Popular Sires – in a breed with a relatively small breeding population where only 10 litters are bred a year, if any one bitch or dog is responsible for a large proportion of the litters bred then the gene pool will be reduced. Bitch owners and stud dog owners should therefore consider whether repeated use of the same sire (same is true for a bitch) will have a positive effect on the breed, or whether it will simply reduce the options for future generations
2. Repeat matings – many geneticists advise that whilst repeating a mating may add to the breeders own stock of ‘winners’ it has little benefit to the breed’s gene pool, simply reducing the variation available. Also if you are repeating a mating simply because one of the pups was outstanding, and the rest were not – why should repeating the mating produce any others of the high quality. Often you will understand more about a dog/bitches genetic potential by selecting an alternate breeding partner to see how the puppies from a different litter compare. The advice often given is that a repeat mating is only worthwhile if the first litter produced a very small number of pups, say 2-3, and therefore it was hard to gauge the value of the mating as a whole. (Also should be noted that two litter sisters mated to brothers from a different line will also on paper be repeat matings, as would a single dog to two sisters).
3. Inbreeding/Line Breeding/Out Crossing – before a mating takes place both the bitch owner and stud dog owner should be aware of any doubling up of ancestors in the pedigree of a prospective litter. Because of the limited dogs in the UK in the early years a number of dogs are fairly closely bred, and when breeding them to other relatives sharing same grandparents/Great grandparents etc this will concentrate the genes involved, and this may increase the likelihood of the pups inheriting the same genes from both parents. For some breeders, inbreeding increases the chance a ‘type’ being defined on a pup for others it is seen as a way to increase the risk of genetic conditions which are harmful, as two copies of a deleterious gene maybe inherited. To put this in perspective, in humans the highest inbreeding legally possible is first cousin matings which gives 6.25% inbreeding. It is therefore suggested that all breeders and stud dogs owners familiarise themselves with the Coefficient of Inbreeding for any potential mating (COI) and take this into consideration. NB in some countries the respective Kennel Clubs restrict COI to less than 6%, the KC will not register litters produced from a mating between father and daughter, mother and son, or brother and sister . The SFLS is more than happy to calculate the COI for any mating – please request details from the Health Coordinator. The KC have a wealth of information about COI and health.
4. General health – it is all too easy for breeders to become complacent about the diseases which may affect our breed. The introduction of a gene test for prcd-1 gives some degree of security that dogs with this specific condition will no longer be produced if breeders observe care to gene status for this condition, but the breed does exhibit a number of other genetically inherited conditions (for some the mode of inheritance is likely to be complex); HC (hereditary cataracts), MRD(Multifocal Retinal Dysplasia), PHTVL/PHPV (Persistent hyperplastic tunica vasculosa lentis /Persistent Hyperplastic Primary Vitreous, congenital) for more info see : http://inpractice.bvapublications.com/cgi/reprint/30/1/2?ijkey=nj1eCEHCqrI3g&keytype=ref&siteid=bvajnls and idiopathic epilepsy. In many of these conditions the age of onset can be varied – and therefore if breeding from older dogs there maybe increased confidence that breeding stock having been screened for such conditions maybe free of the disease. Conversely when breeding from young dogs there maybe increased risk of breeding from a dog which will go on to develop such a late onset condition. Therefore the respective age of dam and sire may be a reasonable consideration when planning a litter.