old English sheepdog, breed of large, wiry working dog developed in England in the early 19th cent. It stands from 21 to 25 in. (53.3-63.5 cm) high at the shoulder and weighs from 55 to 65 lb (24.9-29.5 kg). Its double coat is composed of dense, water-resistant underhairs and a profuse, harsh, curl-free outercoat. It may be any shade of gray, grizzle, blue, or blue-merle, with or without white. The tail is bobbed to approximately 11/2 in. (3.8 cm). The old English sheepdog was originally raised in W England as a drover of sheep and cattle. Today it is popular as a farm dog and show dog and as a pet. See dog.