Effects of space allowance and marketing strategy on growth performance of pigs raised to 165 kg

A total of 976 pigs (PIC 327 × Camborough; PIC, Hendersonville, TN; initially 22.0 ± 1.53 kg body weight [BW]) were used in a 160-d growth study to evaluate the effects of increasing space allowance and varying marketing strategies on growth performance of pigs raised to market weights of ~165 kg. Pens of pigs were blocked by location within the barn and allotted to one of six treatments. Pen served as the experimental unit, and there were eight replicate pens per treatment. The first four treatments consisted of increased initial stocking density and did not utilize topping strategies: (1) 14 pigs/pen (1.17 m(2)/pig), (2) 17 pigs/pen (0.97 m(2)/pig), (3) 20 pigs/pen (0.82 m(2)/pig), and (4) 23 pigs/pen (0.71 m(2)/pig). The fifth treatment began with 25 pigs/pen (0.66 m(2)/pig) and had four marketing events with the heaviest 3 pigs/pen removed on day 93, and additional pigs removed to a common inventory of 20 pigs/pen on day 122 and 17 pigs/pen on day 147 with final marketing on day 160. The final treatment began the experiment with 23 pigs/pen (0.71 m(2)/pig) with three marketing events to achieve a common inventory of 20 pigs/pen on day 108 and 17 pigs/pen on day 147. Pens of pigs were weighed and feed disappearance measured on days 0, 55, 93, 108, 122, 135, 147, and 160. As space allowance decreased from 1.17 to 0.71 m(2)/pig via increased initial pen inventory (treatments 1 to 4), overall average daily gain (ADG) and average daily feed intake (ADFI) decreased (linear, P < 0.001), while gain:feed ratio (G:F) did not differ (P > 0.05). The treatments with multiple marketing events were compared with each other and with the treatment that began with 0.71 m(2)/pig and only marketed once at the end of the study. Overall ADG and ADFI were not different (P > 0.05) among these three treatments. Marketing pigs three or four times improved (P < 0.05) G:F compared with the treatment that began the study with 0.71 m(2)/pig and marketed only once. Reducing floor space allowance for heavy weight pigs decreased intake, which resulted in lower growth rate and final BW, with these reductions occurring before the critical k-value was reached. Total weight gain per pen was maximized with the lowest space allowance and the multiple marketing treatments. Thus, strategic use of pig removals prior to final marketing may allow producers to maximize both number of pigs and total weight marketed through a barn when feeding to heavy weights.