Comparison of three terminal sire breeds for weaning weight of lambs kept under upland grassland conditions in the Northeast of England.

Crossbred females and castrated male progeny of three terminal sire breeds, namely Charollais, Suffolk and Texel, out of Mule ewes (Bluefaced Leicester sires x Scottish Blackface or Swaledale dams) were compared. Analysis of variance revealed that breed, sex and the year of birth were significant sources of variation (P≤0.05) for weaning weight. Suffolk sired lambs were significantly heavier than the Texel sired lambs at weaning (35.78 ± 0.18 versus 35.16 ± 0.18 kg), whereas they were not significantly heavier than the Charollais sired lambs (35.78 ± 0.18 versus 35.37 ± 0.18 kg). There was no significant difference between the weaning weights of Texel and Charollais sired lambs. The lambs born during 1989 were significantly heavier (36.97 ± 0.22 kg) than the lambs born during 1987 (35.96 ± 0.16 kg) and 1988 (33.81 ± 0.18 kg). Birth date and birth weight were significant sources of variation as well. The lambs belonging to fat class 2 were significantly (P<0.05) heavier by 1.05 and 1.65 kg at weaning than lambs belonging to fat class 3L and 3H. The lambs classified as 3L and 3H were weaned at similar weights. This study suggests that breed of sire can affect the weaning weights of lambs and this factor should require careful consideration in practical lamb husbandry.