Historical document of the Coopworth Sheep Society of New Zealand

Coopworth Breeding Stock

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Yarn

The Coopworth Breed

Coopworth Sheep
Produced by the Coopworth Society of New Zealand

The Coopworth is a new breed of sheep developed from crossing the Border Leicester and the Romney and then interbreeding the progeny of this cross.

There are accounts of Border Leicesters having been used for crossing in the early days of the sheep industry but there is little recorded information about their virtues.

The first scientific study of the Border Leicester cross ewe was initiated in 1950 on the Ashley Dene property of Lincoln College. Further extensive investigations were carried out at the Whatawhata Hill Country Research Station, to be followed by an intensive study of interbreeding the Border Leicester x Romney at the Lincoln College Research Farm. The purpose behind these experiments was the realisation by research workers and some farmers at that time that the New Zealand lambing percentages were not high enough. Raising the percentage must be one of the prime objectives of sheep research in the future, and crossing existing breeds with the Border Leicester, which was known to be of high fertility, might offer at least one solution to the problem.

Experiments showed that the first cross ewe by the Border Leicester ram gave a lambing percentage which was 15-30 percent above that of the parent ewe breed. Favourable results raised the question of whether Border cross sheep and Border-Romney in particular, could be interbred to fix a stabilised purebreeding sheep having the desirable characteristics which the first cross sheep undoubtedly had.

The breeding policy at Lincoln was to select for fertility as the interbreeding went on, and to make comparisons with the original F1 ewes and a Romney flock. The comparison suggested that there was a slight decline in fertility from the F1 to the F2 and F3, but there remained a very substantial advantage over the Romney. Meanwhile some interested sheepbreeders continued to interbreed and select very strongly for fertility. Although they had no control flock, their lambing percentages have shown no decline with interbreeding, in fact they claim that it has increased, and their percentage has remained very much higher than their neighbours' or their district average. Encouraged by the results a number of flocks commenced selling interbred rams throughout New Zealand. The breeders concerned believed by the late 1960s that they had third generation (F3) sheep which were of high performance, retaining the desirable characteristicss of the first-cross Border-Romney. A small meeting of those concerned called a general meeting of interested persons in November 1963, at which a Society was formed and after a vote on possible names, the name Coopworth was adopted.

Productive Breed
The Coopworth is a highly productive sheep, bred for high fertility and high lamb growth rate while still producing an 8-12 lb fleece of good crossbred wool. To obtain the most from this potential the Coopworth will show up to greatest advantage on the flat or rolling country where nutrition is good and management is intensive, in which case 130-150 per cent (see Note 1) lambing can be expected and on the better class of hill country where the better growth rate and fertility of the Coopworth means better grown two-tooths, fewer barren ewes and enough twins to put the lambing percentage well over the 100 per cent and up into the 120s. In spite of the higher proportion of twins born to Coopworths, lamb mortality is not increased due to the vigour of the lamb at birth and the very good mothering ability and milk production of the ewe. The excellent performances by Coopworth ewes indicate that the superiority of the Border-Romney has been carried over to the interbred Coopworth, though part of the superiority may be due to the higher inherent growth rate of the Coopworth itself.

The effect of higher growth rates is that drafting percentages are not lowered by the increased