Effect of the feeding level during rearing on performance of Large White gilts. Part 1: growth, reproductive performance and feed intake during the first lactation

Fifty pure-bred Large White gilts were allocated to two feeding levels from 28 kg until service. They were fed a standard growing diet (13.4 MJ digestible energy (DE) per kg; 18.1 % crude protein, CP; 0.96 % lysine) either to appetite (AP) or at 80 % of the AP level (R). Growth rate was reduced by about 20 % in R gilts, whereas feed conversion ratio was unaffected by rearing treatment. First oestrus was detected earlier in AP gilts (234 versus 247 d of age). At service, AP females had larger body weight (190 versus 150 kg) and thicker backfat (20.9 versus 13.4 mm). After service, the reproductive performances of 30 of these gilts were studied during the: first reproductive cycle. All gilts received 2.6 kg/d of a standard diet (12.6 MJ DE/kg; 13.9 % CP; 0.59 % lysine) during pregnancy and were fed ad libitum a commercial lactation diet (13.1 MJ DE/kg; 17.1 % CP; 0.90 % lysine) from day five after farrowing. At farrowing, AP females were larger (257 versus 225 kg) and had more backfat (23.7 versus 17.4 mm) than R ones. Reproductive performance during the first lactation was not affected by rearing treatment, and weaning to oestrus interval was similar in both groups (4.8 d, on average). During lactation, R sows consumed significantly more feed (+ 650 g/d) and lost less backfat depth (1.5 versus 3.8 mm) than AP ones. (C) Inra/Elsevier, Paris.