A comparison of choice and phase feeding for growing–finishing pigs

Abstract

A growing-finishing trial using 72 crossbred gilts (19.7 kg initially) was conducted to evaluate the effectiveness of choice feeding in the production of pigs. Six pens of three gilts were assigned to each of the following feeding systems: (1) conventional three-phase feeding (18–16–14% crude protein; P3), (2) one-phase feeding (16%; P1), (3) three-phase choice feeding (24–14, 22–12, 20–10%; C3) of two diets differing in protein level, and (4) one-phase choice feeding (24–10% throughout; CI). The three growth periods were 20–50, 50–70 and 70–105 kg live weight. All diets were based on barley and soybean meal and contained the same energy level (13.7 MJ DE kg−1). Choice feeding systems (C1 and C3) during the grower period (20–50 kg) increased (P < 0.05) feed intake (1.52 vs. 1.33 kg d−1) and weight gain (801 vs. 731 g d−1) compared with those of phase feeding (P1 and P3). In the 50–105 kg growth phase, feeding systems had no effect on pig growth performance. Feed intake over the entire period (20–105 kg) was higher (P < 0.05) with choice feeding (2.55 kg d−1) than with phase feeding (2.27). Dietary protein intake increased (P < 0.05) by 18% in choice-fed pigs, and more dietary protein was required (P < 0.05) for weight gain from choice feeding than from phase feeding. There were no significant differences in the protein content of the diets selected by C1 and C3 pigs for any period or for the overall experiment. There were no significant effects of feeding system on carcass traits, except that carcass dressing percentage was highest (P < 0.05) for C3 pigs. These results suggest that choice-fed pigs consumed more dietary protein and required more protein for weight gain than pigs in a phase feeding system. Also, growing–finishing pigs do not have the ability to select a protein intake to meet their requirement for protein when they are provided a choice of diets differing in protein content. There was no advantage to using a three-phase choice feeding system rather than a singe-phase choice system. Key words: Choice feeding, protein selection, performance, carcass characteristics, pigs