Selective breeding of livestock for production traits has introduced genetic diseases that cause significant welfare harm across large populations.
The intersection of genetics and welfare in livestock is complex. Breeding for production traits — growth rate, milk yield, muscle mass — has inadvertently introduced or intensified health problems that cause chronic suffering in large populations. Double muscling produces cattle with extraordinary muscle mass but frequent dystocia that harms both calf and dam. Genomic selection tools now make it possible to screen for welfare-relevant traits alongside production, but economic incentives must align with welfare goals for this to happen at scale. Welfare genetics is an important emerging field.