Information on siblings of an individual animal, plus information on the siblings of parents and grandparents, makes it possible for the breeder to apply greater selection pressure against the disease. This results in selection of animals with more ideal breeding values and provides a more rapid reduction of the undesirable trait in the breeding program.

The following breeding selection criteria have been demonstrated to more rapidly and effectively reduce the frequency of undesirable traits:

Breed only normal dogs to normal dogs--using hip displaysia as an example, Table 1 illustrates the outcome of matings based on information extracted from the OFA database. A total of 152,589 progeny were identified where both parents had hip conformation ratings. The percentage of dysplastic progeny increased as the sire's and dam's phenotypic hip ratings decreased from excellent through dysplastic. Reed (2000) reported equal genetic contribution on progeny hip scores from the sire and dam.

T=total number of progeny; N=number and percent of normal progeny; D=the number and percent dysplastic progeny