Intensive selection for production traits in modern dairy breeds has reduced genetic diversity, increasing disease susceptibility with welfare implications.
Genetic diversity loss in modern dairy breeds has welfare consequences through reduced immune function and increased susceptibility to mastitis, ketosis, and other production diseases. The welfare costs of inbreeding depression are distributed across millions of individual animals. Conservation of genetic diversity through heritage breed programmes, semen banking, and informed crossbreeding provides insurance against vulnerability to emerging diseases. Selecting bulls for health traits alongside production traits is increasingly feasible with modern genomic breeding value estimation.