Feed conversion efficiency in livestock production has welfare implications — selective breeding for rapid growth and high output strains physiological systems and compromises animal health.
Feed efficiency in farm animals illustrates the tension between productivity and welfare in selective breeding. Animals selected to convert feed to product with maximum efficiency have been pushed toward physiological limits that compromise health and welfare across multiple systems. High-producing dairy cows experience ketosis and liver disease from negative energy balance; fast-growing chickens suffer leg disorders and cardiac failure. Breeding programmes that incorporate welfare traits alongside productivity are beginning to address these trade-offs, recognising that long-term efficiency is best served by physiologically resilient animals.