Effects of an abrupt change between diet form on growth performance of finishing pigs

A total of 200 finishing pigs (PIC TR4 × 1050; initially 60 ± 4.7 kg) were used in a 58 days growth assay to determine the effects of an abrupt change in diet form from meal to pelleted and pelleted to meal diets on growth performance and carcass measurements. The experiment was designed as a randomized complete block design with 5 pigs per pen and 10 pens per treatment. Diets were fed in 2 phases, day 0-36 and day 36-58 for phase 1 and 2, respectively. Treatments were meal to meal, meal to pelleted, pelleted to meal, and pelleted to pelleted diets for Phases 1 and 2 of the experiment, respectively. For Phase 1 (day 0-36), pigs fed the mean of the pelleted diet had increased (P < 0.01) ADG and G:F compared to pigs fed the mean of the meal diet. For Phase 2 (day 36-58), pigs fed the pelleted diet had increased (P < 0.01) ADG and G:F compared to pigs fed the meal diets. Pigs fed the pelleted diet from day 0 to 58 had increased (P < 0.01) ADG and G:F compared to pigs fed the meal diet from day 0 to 58. For day 0-58, pigs fed the pelleted diet for either Phase 1 or 2, but not both, tended to have decreased (P < 0.11) ADG and G:F compared to those fed the pelleted diet for the entire experiment. Pigs fed the meal then pelleted diet did not differ (P > 0.27) in performance compared to those fed the pelleted then meal diet. No differences (P > 0.19) were observed in dressing percentage, fat thickness, loin depth, or percentage fat free lean index. In conclusion, pigs fed the pelleted diet the entire experiment had increased ADG compared to pigs fed the meal diet. Pigs fed the pelleted diet had the greatest G:F, pigs fed meal the worst, and pigs fed pellets for only part of the grow-finish phase fell between the other treatments.