Dorset Down sheep are thought to have evolved in the early 1800's when Southdown rams were crossed with Berkshire, Wiltshire or Hampshire ewes, according to some historians. Other commentators point to the introduction of Hampshire Down and Southdown blood along the way. Early on, the breed was predominantly distributed throughout areas such as Dorset and Somerset.
It is known for its productivity in cross-breeding programs, where its bloodlines can enhance leanness and growth rates. Their rapid growth rates ensure early mature lamb production. For example, within 10 weeks, some lambs can be bought at up to 18 kilograms dressed carcass weight. Dorset Downs are predominantly bred as terminal sires for prime lamb production. They are a medium-sized breed with grey-brown coats.
The ewes are recognised for their prolific breeding behaviour, as well as desirable mothering traits. Dorset Down fleece is spring and full handling, with average staple lengths between 50-88 mm, and fineness of 26 microns. This wool is ideal for hosiery or added blends as it improves elasticity and handling quality.
On average, rams generally weigh around 100 kilograms and some remain productive until 9 years of age. Dorset ewes can reach weights of around 70 kilograms and can procreate every year, often producing twins.
Dorset Down sheep were introduced into Australia in 1939, however their popularity here has been somewhat minimal. Since their introduction, flocks have been infused with semen from New Zealand. Flocks are distributed throughout Australia in areas ranging from Back Plains in Queensland, to various parts of central and northern Victoria, as well as parts of South Australia, and Western Australia.