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The Coopworth breed of sheep was developed by a team of scientists at Lincoln College (now Lincoln University) in Canterbury, New Zealand, to increase lambing percentages of Romney ewes when mated with Border Leicester rams. The breed makes up the second largest flock in New Zealand. It is also bred in Australia, parts of Europe, and the United States. The Coopworth is used for both meat and wool. An average fleece weighs 5 kg with a fibre diameter of about 30 to 35 microns〔''Preparation of Australian Wool Clips'', Code of Practice 2010-2012, Australian Wool Exchange (AWEX), 2010〕〔 〕 being in the coarser range of wools with a staple length of between 125 and 200 mm. The live weight of an adult is about 55 kg. ==History== 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% 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. The New Zealand Coopworth Sheep Society controls the selection standards based on recorded performance standards. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Coopworth sheep」の詳細全文を読む スポンサード リンク
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