Popular sire effect

For example, in Staffordshire Bull Terriers there are several popular sires who are used by breeders to produce specific colours that are not favoured in the show ring.

The accumulation of these recessive mutations in the reproducing individuals of a population can cause breed-related diseases in future generations through a phenomenon known as the founder effect.

[6] Diseases attributed to the popular sire effect include copper toxicosis in Bedlington Terriers, rage syndrome in English Springer Spaniels, and histiocytic sarcoma in Bernese Mountain Dogs.

Also known as Impressive syndrome, HYPP causes heavy muscling in carrier horses, which is a desirable trait in the show ring.

However, homozygotes can suffer from severe disease, which manifests as attacks of muscle twitching, weakness, collapse, and death.

[11] Studbooks and other forms of pedigree tracking can be useful tools to combat the problem of the popular sire effect and advise breeding decisions that will enhance genetic diversity.

In any population that is overly-inbred and at risk, breeders should run pedigree analyses and genetic testing for deleterious alleles in each individual before making their breeding decisions.

[12] Actions to limit the use of popular sires have been recommended to reduce the loss of genetic diversity in individual breeds.

[13] The Norwegian Kennel Club recommends that no individual dog should have more offspring than the equivalent of 5% of the number of puppies registered in its breed during a five-year period.