Effects of Texel or Rouge de l'Ouest genes in lowland ewes and rams on eweprolificacy, lamb viability and weaned lamb output

An evaluation of the effects of the proportion of Texel or Rouge de l'Ouest (Rouge) genes in ewes (0, 0.5 or 1.0; the remainder being Greyface (Border Leicester X Scottish Blackface)) on prolificacy, lamb viability and lamb o utput was undertaken. A comparison of Texel and Rouge sires was carried out on Greyface, Texel and Rouge ewes. Prolificacy was higher in Greyface comp ared with Texel ewes (P = 0.06) but was lower in Greyface compared with Rou ge ewes (P < 0.001). Prolificacy was similar in Greyface and Texel X Greyfa ce ewes mated to Texel rams and in Greyface and Rouge X Greyface ewes mated to Rouge rams. The level of dystocia was similar in Greyface and Texel X G reyface ewes but significantly higher in Texel ewes (P<0.001). The proporti on of Rouge genes in the ewe had no effect on the level of dystocia. Litter weight of lambs at birth was significantly heavier in Greyface (P < 0.001) and Texel X Greyface (P < 0.01) ewes compared with Texel ewes. The proport ion of Rouge genes in the ewe had no significant effect on litter weight. L amb mortality (no. of lambs born dead and died birth to weaning) was signif icantly greater with Rouge ewes compared with the other ewe breed types (P < 0.001). The number of lambs which died from birth to weaning was lower wi th Texel X Greyface compared with Greyface ewes (P < 0.01). Expressed on a unit metabolic weight basis, Greyface ewes produced a significantly greater weight Of lamb compared with Texel (P < 0.05) and Rouge ewes (P < 0.001). Texel X Greyface cu,es produced a significantly greater weight of Texel-sir ed lamb compared with Greyface (P < 0.01) and Texel ewes (P < 0.001). Sire had a significant effect on a number of parameters. The number of prod uctive ewes was significantly lower in ewes mated with Texel sires (P < 0.0 01). Lamb birth weights and pre-weaning growth rates were greater with Roug e sires (P < 0.05). Number of lambs weaned per ewe lambed was significantly greater with Tex-el sires (P < 0.01). Overall weight of weaned lamb produc ed per ewe was not significantly affected by sire breed.