With time the breed type changed, according to changes in demand. When the need for working oxen declined during the 19th century, the breed became smaller, bulkier and put on more meat and fat. The back-fat could grow to 15 cm. (...) In the sixties the extremely well-fleshed bulls averaged 835 kg only, standing 135 cm at the withers. During the seventies the Hereford was bred for larger size and longer bodies were achieved through selection and by the use of American Herefords. The Polled Hereford imported from the USA is responsible for the polled condition in 85% of the British Herefords of today. The cows average 140 cm and weigh 600-800 kg; the bulls average 152 cm and weigh 1,000-1,200 kg. The highly hereditary colour pattern of the light to dark red Hereford - the white face, withers, chest, bottom line, tail switch and feet - make Herefords and their offspring easily distinguishable from other cattle; for this reason the breed is popular in commercial crossbreeding with dairy cows. At an age of 21 months the Hereford weighs 540 kg, thus it is ready for slaughter six months earlier than continental breeds.
The North-American Hereford is of large stature. Indeed, by using these sires the British Hereford has been re-bred to its original large size. Today, with no evident distinction between the British and the American Hereford, the external description of the breed corresponds with the original Hereford.