From pedigrees to practicality: an interactive tool for cat breeding

Breeding programs for companion animals are increasingly relying on accurate inbreeding coefficients to maintain genetic diversity and limit the occurrence of deleterious traits. To bridge the gap between advanced genetic tools and everyday breeder practice, we developed pawlineR, a streamlined, browser-based application that leverages R libraries to automate pedigree entry, validate parent-offspring relationships, and calculate the inbreeding coefficient (F) in real time. A historical dataset of 70 cats was used to evaluate the tool (pawlineR). Among these animals, 24 showed moderate to high inbreeding values (0.063-0.375). "Virtual breedings" allow users to simulate hypothetical offspring and test potential inbreeding risks before committing to real matings, promoting proactive decision-making. Manual validation using Wright's formula confirmed the accuracy of the tool's calculations. Accuracy depends on pedigree completeness. By offering user-friendly interfaces and stable, long-term pedigree storage, this application helps cat breeders track F across generations. Overall, the tool reduces technical barriers, supports routine breeding management, and can be extended to other species.