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a small to medium-sized dog with long hair, particularly under the body and from behind the legs, a short, docked tail, and low set, long ears. There are two varieties, usually regarded as distinct breeds: The English Cocker spaniel is larger and taller (15 to 16 inches), and a longer muzzle, somewhat like that of a setter. The American Cocker spaniel is smaller (14 to 15 inches tall), has a short muzzle, large, prominent eyes and profuse coat. The breeds are, among other things, affected by an inherited renal cortical dysplasia, seborrhea, glaucoma, progressive retinal atrophy, cataracts, neuronal ceroid lipofuscinosis, hemophilia A, factor X deficiency, patent ductus arteriosus and intervertebral disk disease.