Many definitions are used to describe animal welfare. The definition by the American College of Animal Welfare is that animal welfare “refers to the state of the animal.” Definitions often include the different aspects of animal welfare, as for the definition by David Fraser, which includes an animal's physiology, ability to perform species-typical behavior, and the animal's emotional state, where good welfare is a combination of satisfactory levels in all of these realms. Welfare is on a continuum and may be considered poor, adequate, or good.
"Animal shelter medicine," or simply "shelter medicine," traditionally refers to veterinary practices used to manage the health of populations of animals handled by municipal animal shelters (“pounds”) and private animal welfare or adoption agencies.
Companion animals are commonly considered to be family members, and "human-animal bond" has become a household term. More than half of all households in the US have at least one pet, with dogs and cats remaining the most popular species, although specialty and exotic animals continue to become more common as pets. Results of a 2016 study indicated that dogs were examined by a veterinarian more than twice as often as cats and that about half of cat owners did not obtain routine/preventive care for their cats, compared with 21% of dog owners.