The Leonberger dog breed has lost considerable genetic diversity due to a bottleneck in the last century despite its increasing size in recent years. The heavy use of popular sires led to high levels of relatedness among breeding dogs, resulting in high rates of inbreeding and the spread of undesirable genetic traits within the breed’s gene pool, explaining the high prevalence of certain neurodegenerative disorders and cancer. Preserving the current genetic diversity is possible by increasing the number of individuals in breeding programs while restricting the number of litters per sire/dam as well as the number of repeated matings, and minimizing coancestry among the selected parents. In addition, careful outcrossing might help optimize long-term genetic diversity and contribute to the sustainability and health of the population.
