Effects of proportion of pigs removed from a group and subsequent floor space on growth performance of finishing pigs1

Abstract

The effects of the proportion of pigs removed from an established group and subsequent floor space on growth performance during the final 19 d of the finishing period were evaluated using 28 pens of mixed-sex crossbred pigs (mean initial BW = 113.4 +/- 0.57 kg; n = 1,456; approximately 52 pigs per pen). A randomized block design was used with four pig-removal treatments: 1) 0% of pigs removed [Control], 2) approximately 25% of pigs removed, 3) approximately 50% of pigs removed, and 4) approximately 50% of pigs removed and floor and feeder spaces/pig decreased to equal those of Control. A block consisted of four pens with the same number of pigs and sex ratio per pen and with similar initial BW. Pens within blocks were randomly allocated to treatment, and the heaviest animals were removed from Treatments 2, 3, and 4 at the start of the study. Group size and floor space/pig for Treatments 1, 2, 3, and 4 were 52 and 0.65 m(2), 39 and 0.87 m(2), 26 and 1.30 m(2), and 26 and 0.65 m(2), respectively. Each pen contained a six-place feeder that provided 212 cm of total trough space; however, only three-places were accessible to pigs on Treatment 4. Compared with Controls, removing 25 or 50% of pigs resulted in increased (P < 0.001) ADG by 20.6 and 21.0%, ADFI by 10.8 and 7.9%, and G:F by 7.7 and 14.3%, respectively. Average daily gain by pigs on Treatment 4 (50% removal rate and decreased floor and feeder spaces) was greater (P < 0.05) than that of the Controls, but lower (P < 0.05) than that of Treatment 3 pigs (50% removal rate, no adjustment in floor or feeder spaces). No differences were observed among treatments for either morbidity or mortality. These results indicate that removing 25 or 50% of the heaviest pigs from groups of finishing pigs increased growth rate of the remaining pigs, and that the improved performance was only partly due to increased floor and feeder spaces.

Evaluating the removal of pigs from a group and subsequent floor space allowance on the growth performance of heavy-weight finishing pigs1

“…Growth performance results from the current study agree with previous research examining the impact of removals on finishing pig growth performance (Woodworth et al, 2000;DeDecker et al, 2005;Jacela et al, 2009) in the sense that removing heavy-weight pen mates from a pen results in the remaining pigs having increased ADG and ADFI compared to pigs in intact pens. Interestingly, Bates and Newcomb (1997) and Woodworth et al (2000) observed no impact of pig removal on the G:F of those animals remaining.…”

“…After the removals occurred, BW CV numerically decreased for pigs remaining in pens on the 2:2:2 and 2:4 removal strategies, but only the 2:2:2 removal strategy CV was significantly less (P = 0.004) than that of pigs in pens initially provided 0.91 m 2 of floor space. On d 95 prior to removals, the 2:2:2 removal strategy pigs had less (P < DeDecker et al (2005) concluded that BW variation within pen was reduced with the removal of the heaviest pigs, but the rate of reduction was dependent on the number of pigs removed and the time of measure after removals. Previous work by DeDecker et al (2002) concluded that removing the heaviest 25% of the pen reduced within-pen BW variation, but by 21 d postremoval the BW variation was similar regardless of removal strategy.…”

“…Interestingly, Bates and Newcomb (1997) and Woodworth et al (2000) observed no impact of pig removal on the G:F of those animals remaining. Alternatively, DeDecker et al (2005) observed an improvement in feed efficiency for pigs remaining in pens after the removals were conducted. Also, Jacela et al (2009) observed improved feed efficiency for pigs remaining in pens after removals occurred compared to intact pens.…”

“…DeDecker et al (2005) concluded that the improved growth performance of pigs was the result of increased feed intake from increased pen resources that were provided after pigs within the group were removed. One resource that has clearly been shown to impact growth of finishing pigs is floor space allowance (Gehlbach et al, 1966;Jensen et al, 1973;Moser et al, 1985).…”

Influence of pig rearing system on animal performance and manure composition

“…The lower ambient temperature in the OUT system may explain the higher feed intake of these animals and, consequently, their faster growth rate, in accordance with the well-established effects of ambient temperature on the growth performance of ad libitum fed pigs (Le Dividich et al, 1998). Another explanation is the larger floor space in the OUT system compared with the CON system that provides an easier access to the feeder, in particular at the end of the fattening period, thus giving rise to higher growth rates (Hamilton et al, 2003;DeDecker et al, 2005). Higher feed intake and growth rate of pigs finished in enriched (straw, 3.5 m 2 /pig) compared with barren (slatted floor, 0.76 m 2 /pig) environments have been reported by Beattie et al (2000), in agreement with the present results.…”