The Coopworth was developed between about 1956 and 1968 at Lincoln College (now Lincoln University), near Christchurch in the Canterburyregion of the South Island by researchers under Ian Coop.[4]: 788 [2] The aim of the project was to increase the prolificacy or lambing percentage of ewes.[4]: 788 To this end, New Zealand Romney ewes were put toBorder Leicester rams; the Border Leicester was at that time the most prolific breed in New Zealand. Successive generations were then selectively bred based on strict performance recording for factors including fertility, maternal qualities, rate of growth and fleece weight.[5][3]: 28 Results came fast – by about the fourth generation the cross-bred line was thought better than a direct Romney–Border Leicester cross, despite the benefit of heterosis in the latter.[4]: 788 [5]Abreed association, the Coopworth Sheep Society of New Zealand, was formed in 1968 after a meeting of breeders.[4]: 788
The Coopworth soon became widespread. By 1984 it was the second-most numerous breed in New Zealand after the Romney, constituting almost 20% of the national flock and almost half the number of Romneys; in 2000 it represented about 10% of the whole population, while the Romney made up almost 60%.[3]: 20
It was soon exported to Australia (from 1975), to the United States (from 1970) and to some European countries.[4]: 788 [3]: 28
The Coopworth looks much like the Romney, but is rather larger.[3]: 28 It is of medium size: mature ewes weigh about 55 kg,[4]: 788 rams some 50–70 kg.[3]: 16 It is polled, white-faced and white-woolled; the face and legs are free of wool.[3]: 16 It is a lowland sheep, more suited to improved lowland pasture than to hill country.[3]: 28
The Woodlands Coopworth is a strain within the Coopworth breed, characterised by an X-linked gene which increases ovulation by about 40%, and so contributes to greater fecundity.[4]: 788
The Coopworth is reared for both meat and wool. Fleeces weigh about 5 kg; staple length is in the range 200–230 mm, with a fibre diameter of about 35μm (Bradford count 48/46s). The wool is used for clothing, for hand-spinning, and in carpet blends.[3]: 16
V. R. Clark (1994). Evolution and establishment of the Coopworth breed 1950–1991. In: George H. Davis (editor) (1994). Lab Coats to Gumboots. New Zealand Society of Animal Production, Occasional Publication No. 13. 1994: 107–133.
