Lamb survival, growth characteristics, carcass weight and GR values in pure Corriedale and Texel, Hampshire Down, Southdown and Suffolk sired heavy lambs

Abstract

The effect of the sire bre (Corriedale: C; Texel: TX; Hampshire Down: HD; Southdown: SD and Suffolk : SF) on the performance of 500 C sheep lambing and growth rate, live weight, fat score, hot and cold carcass and tissue thickn s in the GR point of heavy lambs was evaluat . Sheep were mat in autumn. From lambing and until shipment , the animals graz in a pasture of Trifolium repens, Lotus corniculatus and Festuca arundinacea. Death rate of lambs was low (9%) and proportion of assist deliveri was l s than 4 %. For both variabl the higher values were for the SF mated ewes . The crossbreeding show comparative advantages over the pure breed concerning born live weight (3,5; 3,6; 3,9; 4,0 and 3,4 kg; SD, TX, HD, SF, C, respectively; P£ 0,01), growth rate (220, 231, 234, 248 and 206 g day; TX, SD, HD, SF, C, respectively) and finish live weight (33,4; 34,7; 35,2; 37,3 and 31,5 kg, TX, SD, HD, SF and C, respectively; P£ 0,0001), particularly HD and SF rams. SD, HD and SF crossbred animals had a carcass weight superiority varying from 11 to 20% relat to pure Corriedale lambs (16,4; 16,9; 17,8 vs 14,8 kg, respectively; P£ 0,0001), TX crossbr animals which was similar to the pure on (15,9 vs 14,8 kg, respectively; P 0,16). At constant carcass weight SF sir lambs had the lower GR tissue depth (9,4 vs. 12,7; 12,3; 11,6 y 12,6 mm; SF, C, TX, HD, SD, r pectively; P£ 0,01). The practical implications of these results are discuss .