FOUNDATION OF THE COOPWORTH BREED
PROFESSOR I.E. COOP
Patron, N.Z. Coopworth Society.
The Coopworth breed had its origins in the immediate post-World War II years when scientists considered that every endeavour should be made to improve lambing percentages, which they considered were much too low. Research was initiated to improve fertility levels through nutrition, reproduction, disease control and breeding.
Lincoln College chose to examine crossbreeding to replace some of the traditional straightbred Romneys and Corriedales with first-cross ewes. The Border Leicester was chosen as the crossing sire, for despite some faults, it was known to have the highest lambing percentage of all breeds available in New Zealand, had good mothering ability and milk production and white wool. Experiments begun in 1950 established that the F1 Border X Corriedale and Border X Romney produced 20-30% more lamb weaned than the straightbreds. These results were adopted and led to the now common use of Border cross ewes.
But there is a limit to the number of such ewes, given the need to have pure Border Leicester and Romney parent flocks. It was thought that if a purebreeding interbred Border Romney could be produced having the characteristics of the first-cross the impact would be far greater. The College, and two or three individual breeders, set about this task. Border Leicester sires and Romney ewes from a range of sources were carefully selected on the basis of production data available. They were crossed to form the foundation F1 stock and then interbred. An essential feature of the whole process was performance recording, with selection (and culling) on the basis of measured performance - number of lambs born or weaned, adjusted weaning weight, fleece weight and quality and easy care. Continuous recording and analysis monitored progress during the interbreeding. To widen the range of environments used, F1 and F2 rams were distributed to first-cross breeders for assessment by them.
By the late 1960s farmers involved in interbreeding programmes believed that their stabilised interbred Border Romneys at the F3-F4 level were at least equal to the first-cross sheep and certainly superior in overall performance to the original Romneys used. This led in 1968 to the formation of a Breed Society, which became known as Coopworth.