Management of genetic defects in breeding programs of species with high prolificacy

Advances in animal breeding have improved productivity but have led to concerns like reduced genetic diversity and the augmentation of the frequency of genetic defects. This increase of the frequency of genetic defects can be attributed to a hitchhiking effect or to genetic drift in populations with small effective population size. The aim of this study was to compare strict culling of carriers of a genetic defect with balanced selection strategies aimed to reducing the frequency of a genetic defect while maintaining genetic diversity and genetic gain in breeding programs of species with high prolificacy. A simulation-based approach was employed to model breeding programs considering different initial frequencies of a genetic defect, selection pressures, and correlations between the genetic defect and a productive trait. Results indicate that a balanced approach can effectively eliminate the defect with no severe consequences on the outcomes of the breeding program but a slight reduction in the genetic progress and the genetic diversity. A high initial allele frequency of the genetic defect and a correlation between the defect and the productive trait makes more complicated to eradicate the genetic defect.