Two experiments are described to investigate the effect of different weights of pigs at 56 days of age on live-weight gain, efficiency of feed utilisation and bacon carcass quality.1. In Experiment I a comparison was made between 32 pairs of weaners, reared on the sow, which weighed 31·0 1b. and 45·4 1b. respectively at 56 days of age. After separation into heavy and light groups the pigs were group fed to bacon weight.The heavy weaners reached 200 1b. eighteen days earlier than the light weaners but this difference was due completely to the slower rate of growth to 50 1b. live-weight. The heavy weaners required 3·59 1b. of meal per 1b. live-weight gain from 56 days of age to bacon weight compared with 3·50 1b. for the light weaners but there was no difference in efficiency of feed utilisation during the period taken to grow from 50 to 200 1b. There were no significant differences between the carcasses apart from an increased flare weight in the light weaners.2. In the second experiment both suckled and early-weaned pigs were reared to 30, 40 and 50 1b. at 56 days of age and then fed individually to 200 1b.The number of days taken to reach 200 1b. was 168·6 for the 50 1b. pigs, 176·6 for the 40 1b. pigs and 182·1 for the 30 1b. pigs; there were no differences due to the methods of rearing. The efficiency of feed utilisation from 56 days to 200 1b. was not affected by method of rearing but as weight increased from 30 to 50 1b. at 56 days, the meal required for a pound of subsequent live-weight gain increased from 3·06 to 3·24 1b.The number of days to increase from 50 to 200 1b. live-weight was 110·4 for the 50 1b. pigs, 109·3 for the 40 1b. and 106·3 for the 30 1b. pigs, again there being no differences due to the methods of rearing. There were no differences in efficiency of feed utilisation from 50 to 200 1b.Neither weight at 56 days nor method of rearing markedly affected the quality of the carcass but there was an indication that 56-day weight caused greater differences in the early-weaned treatments than in the suckled treatments.
