Effect of Nursery Lactose Concentration and Feeding Duration on Subsequent Growth Performance, Fecal Dry Matter, and Fecal Scores in PIC 800-sired Wean-to-finish Pigs

Abstract A total of 1,080 pigs (initially 5.4 ± 0.09 kg) were used in a 160-d study to evaluate the effect of five lactose programs on growth performance and fecal dry matter (DM) in wean-to-finish pigs. Pens of pigs were blocked by body weight and randomly assigned to one of five dietary treatments in a randomized complete block design with 26 pigs per pen and eight pens per treatment. Treatment programs varied in lactose levels and feeding duration. The high lactose program included 18% lactose from d 0 to 7 and 9% lactose from d 7 to 21. The moderate lactose program provided 12% lactose from d 0 to 7 and 6% from d 7 to 21. The low lactose program consisted of 6% lactose from d 0 to 7 only. The no lactose program received lactose-free diets throughout the entire nursery period. The extended lactose program provided 12% lactose from d 0 to 7, followed by 6% from d 7 to 28. Following these lactose-feeding phases, all pigs were transitioned to a common phase 3 nursery diet and subsequent grow-finish diets. Whey permeate served as the lactose source across all dietary treatments. For the nursery period (d 0 to 42), a marginal response in favor of the moderate or low lactose programs (P 0.10) was observed for ADG and ADFI compared with other programs; however, no mean separation was observed in either of the performance criteria. No differences were observed for G:F. Overall (d 0 to 160), a marginal response (P = 0.065) was observed for ADG, where pigs fed the low lactose program had greater ADG than those fed the high lactose program, with other dietary treatments intermediate. No statistical differences between lactose programs were observed for overall ADFI, G:F, removals, mortality, total removals and mortality, or fecal DM on d 6 and 20. In conclusion, increasing lactose intake during the first 4 weeks post-weaning did not improve overall performance or fecal DM. Based on the conditions of this experiment, utilizing 6% lactose during the first week post-weaning was adequate to maximize overall ADG.