Experimental canines have wide usage. Experimental surgery is widely used in all aspects of experimental surgery, such as cardiovascular surgery, brain surgery, limb replantation, organ or tissue transplantation, etc. The medical experimental research canines are one of the most commonly used animals in basic medical research and teaching, especially in physiological, pharmacological, pathophysiological and other experimental studies. For chronic experimental research, due to canines' well cooperation with experiments through short-term training, they are very suitable for chronic experiments, such as conditioned reflex experiment, observation of therapeutic effect of various experiments, toxicology experiment, endocrine gland removal experiment, etc. About Pharmacological toxicological research and drug metabolism research, there are researches like the study on metabolism of sulfonamides and as well as the toxicity test of various new drugs before clinical use. Common experimental canines include beagles, 4-way hybrid canines, Mexican hairless canines and domestic canines (such as Chinese hounds, Tibetan shepherd canines, wolf canines, four eyed canines, North China canines, and northwest canines).