Effects of feeding canola meal or soy expeller at two dietary net energy levels on growth performance, dressing and carcass characteristics of barrows and gilts

Dietary energy level, feeder space, and group size on growth performance and carcass characteristics of growing-finishing barrows and gilts

“…Following floor area allowance recommendations ( k ≥ 0.0335 for slatted floors; NFACC, 2014 ), pens with 18 pigs were not restricted in the floor area as by day 82 (>110 kg) the first pig(s) were sent for slaughter, whereas pens with 22 pigs were restricted in floor area from the end of the Grower 3 phase (~d 57 or ~85 kg) and throughout the Finisher 1 phase but improved weight gain upon shipping the heaviest pig(s) in each pen. This finding matches previous trials we have conducted in this barn where we have seen an effect of floor area allowance after but not before day 60 with pigs starting at similar BW ( Seneviratne et al, 2010 ; Smit et al, 2017 , 2018 ). Pigs often react to lower floor area allowance by decreasing their feed intake and consequently weight gain ( Gonyou and Stricklin, 1998 ; Gonyou et al, 2006 ).…”

“…The low NE diets had a greater inclusion of barley and lower inclusions of wheat grain, field pea or faba bean, and canola oil than the high NE diets. Similar to our previous trials ( Smit et al, 2017 , 2018 ), changes in feedstuffs led to greater NDF and crude fiber content in low vs. high NE diets. Crude fat content was not different between low and high NE diets, which contrasts with many other studies that increased dietary NE level by adding fat to the diet ( Smith et al, 1999 ; Schinckel et al, 2012 ; Lee et al, 2015 ).…”

“…Lower caloric intake when fed a lower NE diet happened in the Grower phases more so than the Finisher phases, which is consistent with gut capacity being limiting in growing but not finishing pigs ( Whittmore et al, 2001 ). Nonetheless, weight gain was not affected by dietary NE level, thus leading to a lower gain-to-feed ratio but greater caloric efficiency feeding low vs. high NE diets ( Smit et al, 2017 , 2018 , and this study). Similar caloric intake in the Finisher phases resulted in no difference in backfat depth for pigs fed low or high NE diets.…”

“…This finding agrees with results from Brumm and Miller (1996) and Rozeboom (2014) , who also did not report an interaction for feed intake between dietary energy level and space allocation. In our previous trials ( Smit et al, 2017 , 2018 ), when 21 pigs were kept in pens with 2 feeder spaces, pigs were able to increase feed intake to maintain growth performance. The one extra pig per pen in the current study was not enough of an increase in group size to make a difference in that regard.…”

“…Considering that feed is the largest cost of production and energy-yielding feedstuffs account for 85% to 90% of feed cost ( Patience, 2013 ), previous research has evaluated decreasing dietary energy density to reduce feed cost. Our research indicated that feeding reduced net energy (NE) diets (≤9.6 MJ NE/kg) to growing-finishing pigs resulted in greater profit (revenue after subtracting feed cost) per pig than feeding traditional NE levels (≥10 MJ NE/kg; Smit et al, 2017 , 2018 ), but pigs must have the ability to increase feed intake to make up for lower caloric density. In pens with high stocking density, where floor area allowance ( Gonyou and Stricklin, 1998 ) may dip below the recommended value as pigs grow, there may be reduced access to the feeder, insufficient trough space, or both, that can limit feed intake and defeat the advantages of feeding low NE diets.…”