Sixty Merino lambs were randomly allotted to one of six feeding levels. The feeding levels were: ad libitum (control) and 0,82; 0,72; 0,65; 0,55 and 0,45 of ad libitum. Feeding levels were calculated from the average weekly feed intake of the ad libitum group. From 25 to 33 kg live mass, the lambs received restricted feeding except for the control group. At 33 kg live mass, half of each group were slaughtered, whilst the remainder were fed ad libitum up to 45 kg live mass when they were slaughtered. The 0,55 and 0,45 groups were prematurely put on ad libitum at 31 and 28 kg live mass respectively because the ad libitum group reached 45 kg live mass before the 0,55 and 0,45 groups reached 33 kg live mass. Individual feed intakes and live masses were determined weekly. With the aid of the allometric-autoregression model, daily feed intake, growth rate and efficiency of feed utilization were calculated during the restriction and realimentation phases. During the restriction phase digestibility of the diet increased, whereas growth rate and efficiency of feed utilization decreased progressively with increasing restriction. During the realimentation phase there were progressive increases in feed intake, growth rate and an improvement in feed utilization from the 0,65 and to the ad libitum group. More severe restrictions decreased feed intake, growth rate, and efficiency of feed utilization progressively.