Scrapie: A point of view

Abstract

Extract

It will probably never be known why New Zealand sheep up to 1952 remained free from the particular slow virus disease called scrapie. Scrapie has occurred for many years in European countries from which many of our earlier sheep breeds were imported. Between 1870 and the early part of this century a wide variety of British breeds of sheep were imported into New Zealand: these included, English Leicesters, Border Leicesters, Lincolns, Shropshires, Suffolks, Scottish Blackfaces, Norfolks, Wensleydales, Cotswolds, Dartmoor sheep, Ryelands, Dorset Horns, Hampshires, Romney Marshes and probably others. However, the main breeds upon which our sheep industry was founded were the Merino and the Romney Marsh. The Merinos came in large numbers from Australia, particularly following the Victorian droughts of 1851–1852. These sheep had been derived from Spain, North Africa, Germany and France. The Romney Marsh sheep, in direct contrast, came from a restricted part of England, namely the south-east counties of Kent and Sussex. The latter breed, either as a pure breed or as one of its main derivative breeds — the Perendale and the Coopworth, now makes up over ninety percent of our sheep population. A most interesting fact is that, in England where scrapie is widely endemic in many breeds of sheep, the Romney Marsh breed is reputed to be relatively free from this disease as a pure breed, but not as a cross-breed.