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.