Effects of feeding pelleted diets without or with distillers dried grains with solubles on fresh belly characteristics, fat quality, and commercial bacon slicing yields of finishing pigs.

One hundred ninety-two pigs were blocked by age and stratified by initial BW (25.7 ± 2.3 kg) into pens (2 barrows and 2 gilts/pen), and within blocks, pens were assigned randomly to 1 of 4 treatments in a 2 × 2 factorial arrangement, with main effects of diet form (meal vs. pelleted) and distillers dried grains with solubles (DDGS) inclusion (0% vs. 30%). Pigs were slaughtered after a 91-d feeding trial, and carcasses were fabricated after a 24-h chilling period. Belly dimensions and flop distance were measured, and an adipose tissue sample from each belly was collected for fatty acid analysis. Bacon was manufactured at a commercial processing facility before being returned to the University of Illinois Meat Science Laboratory for further evaluation. Although bellies from pigs fed pelleted diets were 5.3% heavier ( < 0.01) than bellies from meal-fed pigs, belly weight as a percentage of chilled side weight ( = 0.55) and fresh belly dimensions ( ≥ 0.11) were not affected by diet form. Slab bacon weight and cooked yield were greater ( ≤ 0.01) for bellies from pellet-fed than meal-fed pigs. Despite pellet-fed pigs having a 3.1-unit greater iodine value (IV) than meal-fed pigs, there was no effect ( ≥ 0.16) of diet form on commercial bacon slicing yields. Bacon slabs from pellet-fed pigs produced more ( < 0.01) total bacon slices, but 3.1% fewer ( < 0.01) slices per kilogram than slabs from meal fed pigs. Inclusion of 30% DDGS reduced belly thickness ( < 0.001), flop distance ( < 0.001), and initial belly weight ( = 0.04) by 0.32 cm, 4.97 cm, and 2.85, respectively, and increased ( < 0.001) belly fat IV by 7.1 units compared with bellies from pigs fed 0% DDGS. Feeding 0% DDGS produced more ( < 0.01) total bacon slices than feeding 30% DDGS. Distillers dried grains with solubles inclusion had no effect on slice yields ( ≥ 0.14) or slices per kilogram ( = 0.08). Overall, bellies from pellet-fed pigs were heavier and had greater IV but did not differ in commercial slicing yields from meal-fed pigs. Feeding pigs 30% DDGS produced thinner, softer bellies with greater IV, but slicing yields were not different from bellies of pigs fed 0% DDGS. Thus, swine producers can feed pelleted diets, without or with 30% DDGS, without negatively affecting commercial bacon slicing yield.

Effects of time after a second dose of immunization against GnRF (Improvest) independent of age at slaughter on commercial bacon slicing characteristics of immunologically castrated barrows.

The objective was to determine the effects of time after a second dose of anti-GnRF immunization on fresh belly characteristics and slicing yields of immunologically castrated (IC) barrows, physically castrated (PC) barrows and gilts slaughtered at 24 weeks of age. The second dose was staggered so that IC barrows were slaughtered at 4, 6, 8, or 10 weeks after the second dose. Fresh belly characteristics (N=141) were collected at slaughter and bacon was manufactured commercially. The main effects in the model were treatment and the random effects of block and block within replication. Thickness, flop distance, and lipid content increased (L; P<0.04) and iodine value tended to decrease (L; P=0.08) with time after the second dose in IC barrows. Slicing yields increased with time after the second dose (L; P<0.01), but were similar (P=0.11) among sexes. Increasing time of slaughter after second anti-GnRF dose improves fresh belly and bacon slicing characteristics in IC barrows.

Effects of immunological castration (Improvest) on further processed belly characteristics and commercial bacon slicing yields of finishing pigs.

Objectives were to compare fresh belly characteristics, further processed belly characteristics, and commercial bacon slicing yields of immunologically castrated (IC) barrows, IC barrows fed ractopamine hydrochloride (IC+RAC), physically castrated (PC) barrows, intact males, and gilts. One hundred eighty-eight bellies from pigs housed in single sex pens (n = 48) slaughtered at 130 kg ending live weight were evaluated for flop distance, length, width, thickness, and fatty acid composition. Bellies were injected, thermally processed, and sliced according to standard protocols at a USDA federally inspected facility. Complete slices were sorted by trained plant personnel. Then, sliced bellies were individually packaged to maintain anatomical orientation. The effects of treatments were analyzed as a generalized linear mixed model with pen of pigs serving as the experimental unit for all comparisons. Belly thickness was not different (P ≥ 0.11) in bellies from IC barrows (3.74 cm) compared with bellies from IC+RAC (3.60 cm), PC barrows (3.94 cm), or gilts (3.64 cm); however, bellies were 0.42 cm thicker (P < 0.01) in IC barrows compared with intact males. Iodine value was not different (P ≥ 0.06) in bellies from IC barrows (68.26) compared with bellies from IC+RAC (69.78), PC barrows (67.55), or gilts (69.45); however, iodine value was 2.32 units less (P < 0.01) in IC barrows compared with intact males. Green weight was not different (P ≥ 0.09) in bellies from IC barrows (4.88 kg) compared with bellies from IC+RAC (5.11 kg), PC barrows (5.10 kg), or gilts (4.79 kg); however, green weight was 0.56 kg greater (P < 0.0001) in IC barrows compared with intact males. Pump uptake and cooked yield was not different (P ≥ 0.15) among treatment groups. Slicing yield (as a percentage of green weight) was decreased (P ≤ 0.01) in bellies from IC barrows (93.61%) compared with bellies from PC barrows (98.42%) or gilts (98.19%); however, slicing yield was not different (P ≥ 0.11) among bellies from IC barrows, IC+RAC, or intact males. Overall, fresh belly characteristics of IC barrows were analogous to PC barrows and gilts, but commercial slicing yields of bacon manufactured from IC barrows were less than both PC barrows and gilts.

Effects of immunological castration and distiller's dried grains with solubles on carcass cutability and commercial bacon slicing yields of barrows slaughtered at two time points.

Male pigs were randomly assigned to a castration method at birth and allotted to 48 pens (28 pigs/pen). Physically castrated (PC) barrows were castrated at 2 d of age; immunologically castrated (IC) barrows were administered Improvest (GnRF analog diphtheria toxoid conjugate; Zoetis, Kalamazoo, MI) at 16 and 20 wk of age. Distiller's dried grains with solubles (DDGS) feeding strategies included either 0% DDGS (control), 30% DDGS (30% DDGS) fed from 6 wk of age to slaughter, or 30% DDGS fed from 6 wk of age to second dose of Improvest and then fed 0% DDGS until slaughter (withdrawal). Four barrows closest to the median pen weight at 4.5 wk after second dose were selected for evaluation; two were randomly selected and slaughtered at 5 wk and the other two at 7 wk after second dose. Data from each slaughter time were analyzed independently as a 2 × 3 factorial design with pen as the experimental unit. At 5 wk after second dose, bone-in lean cutting yields were 2.63% units greater (P < 0.01) in IC when compared to PC. Bellies were thicker (P < 0.01) and tended to have greater belly flop distances (P = 0.07) in PC compared to IC, however iodine values (IV) were not altered (P = 0.84). Carcass traits (P ≥ 0.10), cutting yields (P ≥ 0.43), and fresh belly characteristics (P ≥ 0.08) were minimally affected by DDGS feeding strategy. Bacon slicing yields (percentage of green weight) were 6.10% units less (P < 0.01) in IC compared with PC. At 7 wk after second dose, bone-in lean cutting yields were 1.57% units greater (P = 0.03) in IC compared with PC. Distiller's grains feeding strategy had no effect (P ≥ 0.83) on boneless carcass cutting yields in IC; while in PC, these yields were 2.32% units less (P < 0.02) in control-fed barrows when compared to other feeding strategies (castration method × feeding strategy; P = 0.03). Bellies from PC tended to be thicker (P = 0.07) and have similar flop distances (P = 0.44) and IV (P = 0.54) when compared with IC. Iodine value was greater (P = 0.03) in 30% DDGS-fed barrows compared with control-fed barrows. Bacon slicing yields (percentage of green weight) were 4.27% units less (P = 0.05) in IC compared with PC. These data suggested that while bacon slicing yield was reduced in IC barrows fed control and 30% DDGS compared with PC barrow counterparts, withdrawal of DDGS improved bacon slicing yields of IC barrows.

Growth and carcass characteristics of cull cows after different times-on-feed.

Cull cows (N = 48) of similar age from Angus and Hereford breed types were assigned to one of four feeding periods (0, 28, 56 or 84 d) and subdivided into two groups, one implanted with Synovex-H and a non-implanted control. Cows were fed a high energy diet and slaughtered at the end of each feeding period. Average daily gain and feed efficiency were evaluated on each animal during the trial. The following carcass traits were evaluated: USDA yield and quality grade characteristics, boning yield, muscle weights, bone weights, pH and Warner-Bratzler shear force of the longissimus muscle. The left side of each carcass was boned and proximate analysis was determined. No significant implant effects were encountered for any of the traits evaluated; therefore, data were pooled and evaluated by feeding period only. Carcass weight and boneless forequarter and hindquarter tissue weights increased significantly between each feeding period; percent kidney, pelvic and heart fat (KPH) and yield grade did not differ (P greater than .05) until d 56 and 84, respectively. Quality grade and marbling scores improved (P less than .05) between 28 and 56 d of feeding. Biceps femoris weight changed during the 84-d experiment from 4.1 kg on d 0 to 5.3 kg on d 84 (P less than .05). Proximate analysis of the boneless tissue indicated an increase (P less than .05) in extractable fat of approximately 6% for each feeding period (6.3% fat on d 0 to 25.4% on d 84).(ABSTRACT TRUNCATED AT 250 WORDS)