A COMPARATIVE TRIAL OF CROSSBRED EWES BY FINNISH LANDRACE AND OTHER SIRES

A comparison lasting 3 years has been made of 5 types of crossbred ewes produced by mating Border Leicester, Clun Forest, Dorset Horn, Finnish Landrace and Tasmanian Merino rams to Scottish Blackface ewes. Data from a total of 576 ewe years became available. 2. In body weight at mating time when they were 7, 19 or 31 months old, the Border Leicester and Dorset Horn crossbred ewes were heaviest, followed by Cluns. Finnish and Merino crossbreds were about 15–20% lighter than the Border Leicester crossbreds. 3. In fleece weight, Finnish crossbreds were lower by about 1·0—1·5 lb relative to Border Leicester crossbreds. 4. In fertility, Finnish crossbreds were highest with 1·5, 2·0 and 2·3 lambs born per ewe lambing at ages 1, 2 and 3 years respectively. The corresponding averages for the combined Border Leicester, Clun and Dorset Horn crossbreds were 1·1, 1·6 and 1·6 and for Merino crossbreds 1·0, 1·1 and 1·2. Numbers weaned were similarly ranked. 5. Lambs out of crossbred ewes showed a sequence of group differences in weight at birth and at weaning corresponding to those shown by their mothers at mating time. The heaviest lambs were produced by Dorset Horn and Border Leicester crossbreds, and the lightest by Merino crossbreds. As a percentage of ewe weight at mating, lamb weight at weaning was highest for the Finnish group. 6. In terms of litter weight at weaning, fitted values for the Merino group were the lowest while those for the Finnish group were the highest. The other three groups gave similar and intermediate values. © 1968, British Society of Animal Science. All rights reserved.