Effect of floor space in the nursery and grow-finish periods on the growth performance of pigs

Two studies were carried out over two 4-week periods (week 6 to 10 post-weaning in Study 1 and week 12 to 16 post-weaning in Study 2) to determine the effects of floor space in the nursery and grow-finish periods on the growth performance of pigs. In both studies, subsequent growth performance at an equal floor space across treatment levels was also evaluated over a 2-week period immediately following the floor space evaluation period. Both studies were conducted as randomized complete block designs (blocking factor = day of start of test) with 5 floor space treatment levels (0.21, 0.27, 0.33, 0.39, and 0.44 m2/pig in Study 1; 0.35, 0.45, 0.54, 0.64, and 0.73 m2/pig in Study 2). Treatment levels were selected to cover the range likely to be used under commercial conditions and were calculated to provide the same k values in both studies (i.e., 0.019, 0.025, 0.030, 0.035, and 0.041 m2/BW0.67). The estimated weight at the midpoint of the floor space evaluation period (end of week 8 in Study 1 and week 14 in Study 2) was used to calculate the respective k values. All adjustment gates were moved to the back of the pens during the subsequent period, resulting in floor spaces of 0.53 and 0.73 m2/pig in Study 1 and 2, respectively. Study 1 consisted of 15 replicates with 40 pigs per pen for a total of 3,000 pigs. Pens of pigs in Study 1 were reduced to groups of 29 pigs and re-allotted to Study 2 for a total of 2,175 pigs in 15 replicates. During the floor space evaluation periods in Study 1 and 2, ADG was decreased (P 0.05) in morbidity and mortality levels in the subsequent period of Study 2 or either period in Study 1. The results of these studies suggest that decreasing floor space can cause significant reductions in ADG, ADFI, and feed efficiency; however, feed efficiency can be improved by providing increased floor space subsequent to a floor space restriction