Effect of weight, split-weaning, and nursery feeding programs on performance responses of pigs to 105 kilograms body weight and subsequent effects on sow rebreeding interval.

An experiment using a total of 288 crossbred pigs from sows of two parties (1 or 3) were used in a 2 x 2 factorial arrangement of treatments in a randomized complete block design conducted in 12 replicates to evaluate pig weight and split-weaning on performance response to 105 kg BW. Pigs were allotted to two weight groups (4.1 to 5.5 kg or 6.8 to 8.2 kg) at 23 d of age and weaned at two ages (23 or 30 d). The lightweight pigs weaned at 23 d were fed a high-nutrient-dense diet (HNDD) for a 2-wk period, whereas those weaned at 30 d were fed the HNDD for 1 wk. Both groups were fed a corn-soybean meal-dried whey (C-SBM-DW) and a C-SBM diet, each for a 2-wk period. The heavyweight group weaned at 23 d was fed the HNDD for 1 wk, followed by the C-SBM-DW and C-SBM diet, each for 2 wk, whereas those weaned at 30 d were fed the C-SBM-DW diet and the C-SBM diet, each for 2 wk. From 20 to 105 kg, pigs of all groups were fed C-SBM diets that met or exceeded nutrient requirements. Sows that lactated for the additional week had litters of four pigs and were allowed to consume a 15% CP lactation diet ad-libitum, whereas sows weaned at 23 d were fed 1.8 kg/d of a 14% CP diet.(ABSTRACT TRUNCATED AT 250 WORDS)