INFLUENCE OF WEANING ON CARCASS QUALITY, FATTY-ACID COMPOSITION AND MEAT QUALITY IN INTENSIVE LAMB PRODUCTION SYSTEMS

This study investigated the effects of weaning and sex on various aspe cts of production and quality characteristics in 22 male and 18 female lambs of the Rasa Aragonesa local meat breed. Half the lambs were wea ned (W) at 38 to 40 days and half were left unweaned (UW). Both groups were given ad libitum concentrates and cereal straw. Average farm wei ght was 22.1 kg at 78.3 days. Live-weight gain was significantly diffe rent between sexes but not bet il,een W and UW lambs. Dressing proport ion was higher in UW lambs. Significant differences in fatness were fo und between W and UW lambs and between sex of lambs. Among the meat qu ality traits, W lambs had redder and UW lambs paler meat judged by col our a(star) and haem pigment concentration. No statistical differences were found in the other traits except flavour intensity, which was hi gher in UW (66.8) than in W (63.6) lambs on a 1 to 100 scale. All othe r eating quality aspects, in grilled m. longissimus lumborum slices, t ended to be higher in UW lambs. The fatty acid composition of subcutan eous and intramuscular fat depots differed significantly (intramuscula r fat was more unsaturated and polyunsaturated). There were also diffe rences between Wand UW lambs in subcutaneous fat (higher unsaturated i n W lambs). However in intramuscular fat composition only differences in polyunsaturated fatty acids (higher in UW lambs), but not in total unsaturated or saturated, were observed. Fatty acids of less than C16 chain length were higher, in both fat depots, in UW lambs than in W la mbs reflecting greater incorporation of milk fatty acids. Palatability characteristics were not closely associated with fatty acid compositi on except that flavour intensity was correlated with total saturated f atty acids.