Determining the Effects of Energy Concentrations and Diet Forms on Growth Performance of Nursery Pigs

Abstract Our objective was to determine the effects of two different dietary energy concentrations and diet forms on growth performance of nursery pigs. Barrows and gilts (n = 1,300 PIC337×Camborough, initial BW = 6.7±1.40 kg) were used in a 35-day growth trial with 52 pens in two rooms, 13 pens per treatment, and 25 pigs per pen. At the beginning of the trial, pens within each room were formed by segregating pigs into three body weight (BW) categories and gender, and then randomly allotted to one of four treatments in a randomized complete block design. Pigs were fed in three dietary phases and phase changes occurred based on assigned feed budget (Phase 1: 2 kg/pig, Phase 2: 4 kg/pig, and Phase 3: ad libitum until 35d post-weaning). Treatments consisted of a 2 x 2 factorial arrangement with one factor being the energy concentration of the diets with 2 levels (low and high) and the other factor being the diet form with 2 plans (mash throughout phases 1 to 3 or mash in phase 1 and 2 then pelleted in phase 3). Pellet size was 4 mm, and PDI measurements averaged 84.0 and 83.4% in the low and high energy diets, respectively. Growth performance data were analyzed using a generalized mixed model in Minitab and considered pen as the experimental unit. The statistical model considered fixed effects of BW category, energy, diet form, and their interaction, and random effects of room. All data are reported as least square means and considered statistically significant at P < 0.05. There was no evidence for a significant interaction between energy level and diet form (P > 0.10) for any response criteria. Increasing energy of the diet fed to nursery pigs did not result in significant differences (P > 0.10) in overall average daily gain (ADG; 356 and 367 g/d), average daily feed intake (ADFI; 501 and 510 g/d), or feed efficiency (G:F; 711 and 719 g/kg) between low and high energy, respectively. Feeding a pelleted diet in the last nursery phase resulted in increased (P = 0.004) overall ADG (368 vs 355 g/d), increased (P = 0.018) final BW (19.6 and 19.2 kg), and improved (P = 0.002) overall G:F (727 and 702 g/kg) compared with pigs fed mash diets throughout the entire nursery period. There was no evidence for differences in ADFI due to diet form. In addition, no evidence for treatment differences were observed for overall removal and mortality rates. In conclusion, under the conditions of this study, there was no evidence for an energy impact in nursery pig growth performance. Feeding a pelleted diet in the last nursery phase resulted in improvements in overall ADG, G:F, and final BW of nursery pigs.