Effect of stocking rate on pig performance in a wean-to-finish production system

Abstract

Crossbred pigs (n = 1,296) were used in a randomized complete block design to evaluate three stocking rate treatments (22, 27, or 32 pigs pen-1) on growth performance from weaning [5.0 ± 0.01 kg body weight (BW); 15 ± 1 d of age] to 24 wk post-weaning. Floor and feeder spaces per pig were 0.78 m2 and 4.2 cm, 0.64 m2 and 3.4 cm, and 0.54 m2 and 2.9 cm for group sizes of 22, 27, and 32, respectively. During the first 8 wk postweaning there was a tendency for average daily gain (ADG) (511, 505, and 497 g d-1, respectively; P = 0.07) and BW (35.1, 34.7, and 34.3 kg, respectively; P = 0.08) to decrease linearly as stocking rate increased. Moreover, from week 8 to 18, week 18 to 24, and for the overall period (weaning to week 24) both ADG (688, 660, and 635 g d-1 for the overall period, respectively) and BW (121.8, 117.1 and 113.1 kg at week 24, respectively) decreased linearly (P < 0.001) with increasing stocking rate. There were no treatment differences in the coefficient of variation in pig BW within a pen at any stage of the study. Morbidity and mortality rates increased linearly (8.5, 10.2, and 12.7%; P < 0.05) with increasing stocking rate. In conclusion, decreasing group size, thereby increasing floor and feeder space pig-1, reduced morbidity and mortality and increased growth rate after 8 wk post-weaning resulting in heavier pigs at 24 wk post-weaning for the smaller groups. Key words: Pigs, stocking rate, weaning, finishing