Suffolk lambs, weaned at 60 days, were raised in slatted floor pens and fed corn silage, sorghum silage or Coast cross hay (Cynodon dactylon L. Pears) plus concentrate ration (3,5% of live weight) to evaluate their performance, proportion of non-carcass components and carcass dressing and traits. A completely randomized design in a factorial arrangement (tree roughage feed X two sexes) was used. Lambs fed corn silage or sorghum silage showed greater (P<0.05) daily gain (292 and 294g) and smaller (P<0.05) age at slaughter (119 and 118 days) than hay fed lambs (241g and 129 days). Male lambs showed greater (P<0.05) daily liveweight gain (301 and 252g) and smaller (P<0.05) slaughter age (117 and 127 days) than females. The non-carcass components, carcass dressing and joints percentage, subcutaneous fat thickness and fat score did not show differences (P>0.05) between feeds, although, lambs fed corn silage showed greater (P<0.05) percentage of fat (18.7, 16.7 and 17.5%) and more compact (P<0.05) carcasses (241, 232 and 231g/cm) than the other two feeds and smaller (P<0.05) percentage of lean (59.5, 61.1 and 60.6%) than lambs fed sorghum silage. Female lambs showed greater (P<0.05) percentage of fat (19.0 and 16.3%) and smaller (P<0.05) percentage of bones (21.0 and 22.9%) in carcasses than males, without effect (P>0.05) in proportion of muscle (60.0 and 60.7%). Sorghum silage can replace corn silage for feedlot lambs, but grass hay feeding worsens their performance.
feeding; hay; live weight gain; sheep; corn silage; sorghum silage
