365 Effects of weaning ages on growth performance of nursery pigs fed diets with increasing lactose levels during at 7 to 11 kg body weight

摘要

Lactose is an effective carbohydrate source for nursery pigs. Weaning age could influence needs for lactose. Weaning ages can vary among producers depending on preferred management programs. This study aimed to evaluate optimum levels of lactose for pigs at 7 kg BW weaned at different ages. A total of 1,632 pigs were weaned at d21 (d 21.2 ± 1.3) or d25 (d 24.6 ± 1.1). Pigs had a common diet until they reach 7 kg BW. Within a same weaning age group, when pigs reached 7 kg body weight, they were allotted to 4 dietary treatments with 6, 9, 12, and 15% lactose. Feed intake and BW were measured after 10d feeding when pigs reached 11 kg BW. Data were analyzed using the MIXED procedure of SAS for a slope ratio analysis to test effects of lactose levels on growth performance of pigs influenced by their weaning ages. Pigs weaned at d21 had Phase 1 for 11 days whereas pigs weaned at d 25 had Phase 1 for 2 days to reach 7 kg BW. According to the slope ratio analysis, as increasing lactose intake, ADG of pigs weaned at d21 responded greater (P < 0.05, 68.5%) than growth of pigs weaned at d25. There was no change of slope in feed intake of pigs weaned at d 25 by increasing lactose intake. However, G:F of pigs weaned at d 25 responded greater (P < 0.05, 250%) than G:F of pigs weaned at d21. In conclusion, pigs weaned at d21 grew faster from 7 to 11 kg BW as lactose intake increased compared with pigs weaned at d25 potentially because pigs weaned at d21 had an extended time for adaptation and recovery from weaning stress until they reached 7 kg BW.