Abstract
Lactose is a critical nutrient in post weaning diets to help pigs transition from sows’ milk to dry feed. The objective of this study was to evaluate the effects of increasing dietary lactose level on nursery pig performance. For this trial 1,080 weaned pigs (PIC 359 x 1050; BW = 6.24 kg; 21 d) were fed 5 lactose programs using a feed budget. Program A = 24, 18, 7%; B = 20, 14, 5%; C =16, 10, 3%; D = 12, 6, 1%; and E = 8, 2, 0% lactose for Phase 1, 2, and 3; respectively. The feed budget for Phase 1 (d 0–7), 2 (d 7–14), and 3 (d 14–20) was 0.91, 3.4, and 4.5 kg/pig; respectively. A common Phase 4 (d 20–48) diet (0% lactose) was fed ad libitum. There was a quadratic response to lactose level in treatments A through E for Phase 1 ADFI (89, 71, 73, 73, 89 g/d; respectively, P = 0.034) and G:F (1.09, 1.33, 1.14, 1.15, 0.91; respectively, P = 0.042). Treatment A through E Phase 1 ADG was 100, 95, 91, 82, and 82 g/d, and Phase 2 ADG (Linear, P = 0.023) was 322, 313, 318, 304, and 295 g/d; respectively. The result was a linear trend for increased BW at the end of Phase 2 (P = 0.10) for treatments A through E (9.21, 9.10, 9.16, 9.00, 8.86 kg; respectively). Although feed cost/pig increased as lactose level increased (Linear, P = 0.041), there was no significant response in margin over feed cost/pig during the overall nursery period for treatments A through E ($15.31, $16.41, $16.22, $15.87, $16.04; respectively). In conclusion, pig performance improved during Phase 1 and 2 with increasing level of dietary lactose. These results confirm previous research showing the importance of dietary lactose in weaned pig diets.