The effects of dietary net energy on grow-finish performance and carcass characteristics of market gilts managed with immunological suppression of ovarian function and estrus (Improvest).

The objective was to determine the effects of net energy (NE) during the grow-finish period on live performance and carcass characteristics of market gilts managed with immunological suppression of ovarian function and estrus (Improvest®; IMP) compared with market gilts not managed with Improvest (CON). The 104-d study began when 1,008 gilts (11 wk old; average starting weight of 30.8 kg) were allocated by weight to 48 pens with 21 gilts/pen. Half of the pens were randomly selected to be managed with Improvest while the other half of the pens were not managed with Improvest. Three dietary programs differing in their NE were formulated over five dietary phases (according to standardized ileal digestible lysine requirements) to provide an average of 2,218 kcal/kg (low NE), 2,343 kcal/kg (medium NE), or 2,468 kcal/kg (high NE). The experiment was designed as a 2 × 3 factorial with main effects of Improvest management and NE. For the overall study period, there were no significant interactions (P ≥ 0.20) for average daily feed intake (ADFI), average daily gain (ADG), or Gain:Feed (G:F). There were also no significant interactions between Improvest management and NE (P ≥ 0.30) for carcass characteristics. However, IMP gilts consumed more feed (6.8% greater ADFI; P < 0.01), grew faster (5.0% greater ADG; P < 0.01), were less efficient (1.8% lower G:F; P < 0.01), heavier (3.5 kg hot carcass weight; P < 0.01), and fatter (1.9 mm greater backfat thickness and 1.26% less predicted lean carcass yield; P < 0.01). No difference (P = 0.21) in carcass dressing percentage between IMP and CON gilts was reported. For the overall study period, gilts fed low NE and medium NE diets consumed more feed compared with gilts fed high NE diets (6.8% more ADFI for low NE and 5.7% more for medium NE; P < 0.01), and gilts fed low NE diets grew 2.5% slower (P < 0.01) than gilts fed medium NE diets, while gilts fed high NE diets were intermediate and not different from the other NE treatments. This resulted in gilts fed Low NE diets being the least efficient (3.8% lower G:F than medium NE and 7.1% lower G:F than High NE; P < 0.01). Overall, these data indicate that typical Improvest response levels were sustained at each of the NE treatments evaluated in this study as there were no significant interactions for Improvest management and NE; however, consideration should still be provided to the known production impacts of low NE diets.

The effects of dietary net energy on grow-finish performance and carcass characteristics of male market pigs managed with immunological castration (Improvest).

The objective was to determine the effects of dietary net energy (NE) during the grow-finish period on live performance and carcass characteristics of intact male pigs managed with immunological castration (Improvest) compared with physically castrated (PC) male pigs. The 101-d study began when 1,008 pigs (504 intact male pigs and 504 PC male pigs; 10 wk old) were allocated by weight to 48 pens with 21 intact males or 21 PC males per pen. Three dietary NE treatments were fed to pigs using five dietary phases (dietary programs were formulated according to standardized ileal digestible lysine requirements of Improvest males or PC males) to provide an average of 2,212 kcal/kg (low NE), 2,337 kcal/kg (medium NE), or 2,462 kcal/kg (high NE). The experiment was designed and analyzed as a 2 × 3 factorial with main effects of Improvest management and NE. For the overall study period, there were no significant interactions between Improvest management and NE (P ≥ 0.19) for average daily feed intake (ADFI), average daily gain (ADG), or gain:feed (G:F). There were also no significant interactions between Improvest management and NE (P ≥ 0.06) for carcass characteristics. Improvest males consumed less feed (5.3% lower ADFI; P < 0.01), grew faster (5.1% greater ADG; P < 0.01), and were more efficient (11.2% greater G:F; P < 0.01) compared with PC males. Hot carcass weight (HCW) did not differ (P = 0.16) between Improvest males and PC males (attributed to 1.6 percentage unit lower dressing percentage for Improvest males; P < 0.01); however, Improvest males were leaner (0.9 mm less backfat and 0.65% greater predicted lean yield; P < 0.01) compared with PC males. For the overall study period, pigs fed low NE and medium NE diets consumed 7.5% and 4.6% more feed (P < 0.01) than pigs fed high NE diets, respectively, and pigs fed low NE diets grew 1.7% slower (P < 0.02) than pigs fed medium NE and high NE diets. This resulted in pigs fed low NE diets having 4.4% lower G:F compared with pigs fed medium NE and 8.6% lower G:F compared with pigs fed high NE diets (P < 0.01). Pigs fed low NE had 3.0 kg lighter (P < 0.01) HCW compared with medium NE, while high NE had intermediate HCW that did not differ from the other two treatments. Overall, typical Improvest response levels for live performance and carcass characteristics when compared with PC males were achieved for each of the NE treatments evaluated in this study.

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

To benefit from feeding low net energy (NE) diets, growing-finishing pigs must be able to increase feed intake to compensate for lower caloric density, but this might be difficult in pens with a high stocking density. Access to the feeder, trough space, and(or) floor area may limit voluntary feed intake. The objective of this study was to clarify the relationships among dietary NE level, feeder space, group size, sex, and interactions in growing-finishing pigs. In a 2 × 2 × 2 × 2 factorial design, 1,920 pigs (33 kg) housed in 96 fully slatted floor pens (6.1 × 2.4 m) with 2 or 3 feeder spaces, and 18 or 22 barrows or gilts per pen, were fed either low (9.2 MJ/kg) or high (9.85 MJ/kg) NE diets over 5 growth phases (Grower 1: day [d] 0 to 20, Grower 2: d 21 to 41, Grower 3: d 42 to 62, Finisher 1: d 63 to 80, Finisher 2: d 81 to slaughter). Pen body weight (BW) and average daily feed disappearance (ADFD) were measured for each growth phase, biweekly from the start of shipping and at slaughter. Warm carcasses were weighed and graded (Destron). For the entire trial, pigs fed low versus (vs.) high NE diets had 0.119 kg/d greater (P < 0.001) ADFD, but 0.556 MJ/d lower (P < 0.050) average daily caloric disappearance (ADCD), and 0.017 kg/kg lower (P < 0.001) gain-to-feed (G:F). Pens with 18 vs. 22 pigs had 0.062 kg/d greater (P < 0.001) ADFD, 0.730 MJ/d greater (P < 0.010) ADCD, and 0.029 kg/d greater (P < 0.001) average daily weight gain (ADWG). Pigs in pens with 3 vs. 2 feeding spaces had 0.051 kg/d greater (P < 0.010) ADFD, 0.511 MJ/d greater (P = 0.050) ADCD but 0.004 kg/kg lower (P < 0.050) G:F. Pigs fed low vs. high NE diets had 0.6 kg lower (P < 0.050) carcass weight and 0.9 mm lower (P < 0.050) loin depth. Pens with 18 vs. 22 pigs took 2.8 days less (P < 0.001) to reach 130 kg slaughter BW. Pens with 18 vs. 22 pigs had a 0.4 %-point decrease (P < 0.050) in dressing percentage. Feeding low vs. high NE diets reduced (P < 0.001) feed cost by Can$21.87/tonne, $3.34/pig, $0.03/kg gain, and increased (P < 0.05) gross income subtracting feed cost by $1.82/pig. Housing 18 vs. 22 pigs per pen increased (P < 0.010) ISFC by $1.98 per pig. Lack of interactions between NE level, feeder space, and group size for ADFD indicate that low NE diets can be fed to pigs even if they have lower than recommended floor area allowance during part of the finishing phase.

Increasing hybrid rye level substituting wheat grain with or without enzyme on growth performance and carcass traits of growing-finishing barrows and gilts.

New European, fall-planted hybrid rye grown in western Canada is more resistant to ergot and fusarium and has lower content of anti-nutritional factors than common rye. We evaluated the effect of feeding increasing hybrid rye level substituting wheat grain and non-starch polysaccharide (NSP) enzyme inclusion in diets fed to growing-finishing pigs raised under western Canadian commercial conditions. In total, 1,008 pigs (~44 kg body weight [BW]) housed in 48 pens by sex, 21 pigs per pen, were fed diets with one of three rye (var. KWS Bono; KWS LOCHOW GMBH) inclusion levels substituting wheat grain: low (L; one-third of wheat replaced), medium (M; two-thirds of wheat replaced), or high (H; most wheat replaced), either without (WO) or with (W) enzyme inclusion (280 units of ß-glucanase and 900 units of xylanase per kilogram feed; Endofeed W DC; GNC Bioferm) over four growth phases (Grower 2: d 0 to 22, Grower 3: d 23 to 42, Finisher 1: d 43 to 63, Finisher 2: d 64 to slaughter). Pen BW, feed added, and orts were measured on d 0, 22, 42, 63, 76, 91, and at slaughter weight (130 kg). Warm carcasses were weighed and graded (Destron). BW was not affected by either increasing hybrid rye level substituting wheat grain or enzyme inclusion throughout the trial. For the entire trial (d 0 to 76), pigs fed increasing hybrid rye level substituting wheat grain had decreased (P < 0.050) average daily feed intake (ADFI; L 3.05, M 2.98, H 2.91 kg/d) and average daily weight gain (ADG; L 1.01, M 1.00, H 0.97 kg/d). Enzyme inclusion did not affect ADFI but tended (P = 0.080) to increase ADG (WO 0.98, W 1.00 kg/d). Enzyme inclusion improved (P < 0.050) gain-to-feed ratio only in pigs fed the H rye level. Most carcass traits were not affected by either increasing hybrid rye level substituting wheat grain or enzyme inclusion. Increasing dietary hybrid rye level substituting wheat grain increased (P < 0.001) cost per tonne of feed (L 240.28, M 241.28, H 242.20 Can$/kg), but did not affect feed cost per pig or per kilogram BW gain. Enzyme inclusion increased (P < 0.001) cost per tonne of feed (WO 240.36, W 242.15 Can$/kg), but feed cost per pig (WO 82.14, W 80.44 Can$ per pig) and per kilogram BW gain (WO 0.96, W 0.94 Can$/kg gain) were reduced (P < 0.050). In conclusion, fall-planted hybrid rye can completely replace wheat grain in grower-finisher pig diets without affecting feed efficiency, feed cost per pig or feed cost per kilogram BW gain. Inclusion of NSP enzyme would be recommended for diets including high rye levels to improve feed efficiency and ADG.