The influence of particle size and processing method for wheat-based diets, offered in dry or liquid form, on growth performance and diet digestibility in male weaner pigs

In total, 136 entire male (Large White x Landrace) weaner pigs (28 days; 7.4 +/- 0.3 kg) were individually housed and allocated to a 26-day feeding trial of 2 x 2 x 2 factorial design. The factors were (1) feed processing method (meal or steam-pelleted); (2) feed form (dry or liquid), and (3) wheat particle size (average 760 or 664 mu m). Five days post weaning two pigs were removed from each treatment. Particle size had no effect on pig performance. Pigs fed steam-pelleted diets had higher daily gain (446 versus 388 g/day; s.e.d. 14.7), better food conversion ratio (1.20 versus 1.44; s.e.d. 0.05) and were heavier at the end of the 26-day feeding period (17.9 versus 16.8 kg; s.e.d. 0.31) than pigs fed meal diets (P < 0.05). Pigs given liquid diets had higher daily gain (453 versus 381 g/day; s.e.d. 14.7) and 26 days' weight (18.1 versus 16.7 kg; s.e.d. 0.31), but poorer food conversion ratio (1.42 versus 1.22; s.e.d. 0.05) than pigs fed dry diets (P < 0.05). This poorer feed conversion efficiency of liquid fed pigs was largely attributable to increased feed wastage. Liquid-fed pigs consumed more feed in the 5 days post weaning (197 versus 157 g/day; s.e.d. 8.7; P < 0.05). The apparent DE content of the diet was increased (0.5 +/- 0.1 MJ/kg DM; P < 0.05) by either steam-pelleting or finer grinding, but was not affected by liquid feeding.