People feel that they have obligations to the animals that they use and show some degree of care behavior toward them. In addition, animal welfare is an aspect of our decisions about whether animal-usage systems are sustainable. A system that results in poor welfare is unsustainable because it is unacceptable to many people. The quality of animal products is now judged in relation to the ethics of production, including impact on the animal's welfare on immediate features and on consequences for consumers. Because genetic selection and management for high productivity may lead to more disease and other aspects of poor welfare, consumers demand some major changes in animal-production systems. In teaching animal welfare, a clear definition that can be related to other concepts such as needs, health, and stress is needed. The methodology for the scientific assessment of animal welfare has developed rapidly in recent years and has become a major scientific discipline. No veterinary degree course should be approved unless a full course on the science of animal welfare and relevant aspects of ethics and law have been taught. Each country should have a national advisory committee on animal-welfare science, made up of independent scientists, including veterinarians, who can write impartial reviews of the state of scientific knowledge.
