Effect of Phase Feeding, Space Allowance and Mixing on Productive Performance of Grower-Finisher Pigs

SIMPLE SUMMARY: Low space allowance and mixing may affect productive performance in pigs, but it is not clear whether space allowance and mixing interact with each other during the grower-finisher period. In addition, phase feeding is a good strategy used to reduce feed costs and improve feed efficiency, but it may result in nutrient limitations in suboptimal production conditions, e.g., high stress. This study investigated the effect of space allowance, mixing and phase feeding on productive performance of grower-finisher pigs. Three trials were conducted. Space allowance did not affect productive performance in any of the trials. Non-mixed pigs were 5.40 and 5.25 kg heavier than mixed pigs at 21 weeks of age in trial 1 and trial 2. Introducing a second diet with lower lysine/energy ratio from 0.95 to 0.82 g/MJ at 15–16 weeks of age reduced productive performance of pigs by 3.45 and 4.05 kg at 21 weeks of age in trial 1 and trial 2, but not in trial 3 where all pigs were mixed. In conclusion, mixing and reducing lysine/energy ratio from 0.95 to 0.82 g/MJ at 15–16 weeks of age, had a more marked impact on productive performance than a reduction in space allowance from 0.96 to 0.78 m(2)/pig. ABSTRACT: This study investigates the effects of space allowance (SA), mixing and phase feeding (PF) on performance of grower-finisher pigs. Three trials (T) were conducted. In T1 and T2, 345 pigs/trial were moved to finisher stage at 11 weeks of age and assigned to two SAs: 0.96 (n = 15 pens; 10 pigs/pen) and 0.78 (n = 15; 13 pigs/pen) m(2)/pig. Mixing was applied to 5 pens of each SA leading to a 2 × 2 factorial arrangement (SA × Mixing). For PF, 2 diets with 0.95 and 0.82 g SID Lys/MJ NE were applied to 5 pens of each SA (not mixed) leading to another 2 × 2 factorial arrangement (SA × PF). In T3, 230 pigs were moved to the grower-finisher stage at 11 weeks of age, mixed, and assigned to 4 treatments (SA × PF; n = 5 pens). Data were analyzed using general linear mixed models. SA did not affect performance (p > 0.05). Non-mixed pigs were 5.40 (T1) and 5.25 (T2) kg heavier than mixed pigs at 21 weeks of age (p < 0.001). PF reduced performance of pigs by 3.45 (T1) and 4.05 (T2) kg at 21 weeks of age (p < 0.001). In conclusion, mixing and reducing SID Lys:NE ratio from 0.95 to 0.82 g/MJ at 15–16 weeks of age, have a more marked impact on performance than reducing SA from 0.96 to 0.78 m(2)/pig.