Forty Najdi ramlambs weighing 26.6±0.3 kg were utilized in this experiment to determinethe effects of feed restriction followed by realimentation and body weight atthe onset of feed restriction (30 and 36 kg body weights) on performance andcarcass characteristics; feeding and restriction levels were ad libitum,0.75 and 0.60 of the ad libitum intake. All lambs were slaughtered after14 weeks of experimentation. The results showed that, during the feed restrictionphase, average daily gain (ADG) and feed efficiency decreased as the level ofrestriction increased. During the realimentation phase, the 30 kg lambs gainedweights and consumed dry matter (DM) similarly to the ad libitum group,whereas the ADG for the 36 kg lambs of both 0.75 and 0.60 ad libitumgroups were 20 and 43.8% faster than the ad libitum group, respectively.At the end of the trial, final body weight and overall ADG of the realimented30 kg groups were lower than ad libitum group, whereas the ADG of the36 kg groups were not different compared with the ad libitum group. Althoughempty body, hot and cold carcass, empty stomach compartments, empty intestinesand liver weights for the 36 kg groups were not affected by feed restrictionfollowed by realimentation, weights of visceral fat depots, subcutaneous fatand tail fat decreased much more than those of the ad libitum group.Carcass composition of the realimented 0.75 and 0.60 ad libitum groupstended to have 5.1 and 8.8% less lean tissue than the ad libitum groupwhen the restriction started at 30 kg, respectively. On the other hand, therealimented lambs of both 0.75 and 0.60 ad libitum groups tended to be5.1 and 2.8% leaner than those of the ad libitum group when restrictionstarted at 36 kg body weight, respectively. Feed restriction of up to 40% fora 5-week period followed by a 4-week period of refeeding in 36 kg lambs is economicallyfeasible and does not offset production.
