Abstract
Seventy-eight gilts in replicates of three litter-mates were allocated at 135 days of age and 65·4 kg live weight among three treatments. Between allocation and mating gilts were given either 1·78 kg/day (LL) or 2·72 kg/day (LH) diet containing 12·3 MJ digestible energy (DE) per kg and 5·3 g lysine per kg or 2·57 kg/day (HH) diet containing 12·6 MJ DE per kg and 8·1 g lysine per kg. More gilts in the LH and HH groups attained puberty within 200 days of age than LL gilts (41/52 v. 72/26, X2 = 8·9, P < 0·01). Live weight at conception was 93·8, 105·3 and 108·9 kg for LL, LH and HH gilts respectively at a mean age of 203 days. Subsequent reproductive efficiency and sow body weight and backfat changes were not significantly affected by treatments imposed during the early stages of reproductive life.