A veterinary patient is an animal that is being treated by a veterinarian. The term 'PET' is often used to refer to a domesticated animal kept as a companion, such as a dog or cat. Veterinary patients can include any type of animal, including those kept as pets, as well as animals kept for agricultural or other purposes. Veterinary patients may require medical care for a variety of reasons, ranging from routine check-ups to more serious illnesses or injuries.