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.

Objectives were to evaluate the administration of an anti-gonadotropin releasing factor (GnRF) analog on suppression of estrus, consistency of feed intake, and growth performance in market gilts and to investigate the impact the physiological changes would have on carcass characteristics and fresh meat quality. Gonadotropin releasing factor stimulates the anterior pituitary to release luteinizing hormone that acts on the ovary to induce follicle development and indirectly initiates ovulation. Improvest (Zoetis, Kalamazoo, MI) contains an incomplete version of naturally occurring GnRF and causes the production of anti-GnRF antibodies that bind to the GnRF receptor and thus render GnRF inactive. This in turn suppresses estrus in female pigs. Gilts were initially separated into 10 blocks based on age and then within each block allotted to a pen (n = 114; 5 pigs/pen) based on BW. Gilts received the first dose at 12 wk of age and the second dose at 16 wk of age, were exposed to a boar daily from 20 to 26 wk of age, and were slaughtered at 26 wk of age (10 wk after second dose). Meat quality was analyzed on the 2 gilts closest to pen average ending live weight in 5 of the 10 blocks. Pen served as the experimental unit for all data analysis. During the 15-wk finishing period, ADG was 0.03 kg greater (P < 0.01) and G:F was 0.009 greater (P = 0.02) in gilts administered GnRF suppression (treated) compared with untreated gilts (control). The majority of improvements in growth performance were observed from 16 to 20 wk of age (4 wk after second dose), as ADG was 0.07 kg greater (P < 0.001) and G:F was 0.021 greater (P < 0.01) in treated gilts compared with control gilts. Ovarian weights were reduced (P < 0.0001) by 64.15% and gilts exhibiting puberty were reduced by 87.80% (P < 0.001) in treated gilts compared with control gilts. Back fat depth was 3.78 mm greater (P < 0.0001) and estimated lean was 1.31 percentage units less (P < 0.0001) in treated gilts compared with control gilts. With the exception of subjective color, there were no differences (P ≥ 0.12) in meat quality parameters between treated and control gilts. Subjective color was darker (P = 0.03) in treated gilts compared with control gilts. These data suggest market gilts treated with an anti-GnRF analog had suppressed estrus and episodical changes in ADFI, while they had improved feed efficiency, increased ADG, and increased back fat depth when compared with gilts without an anti-GnRF analog treatment.

The objective was to summarize previous literature, using a meta-analysis approach, on the effects of ractopamine hydrochloride (RAC) when fed at doses of 5 to 10 mg/kg for up to 35 d before harvest on carcass cutability and belly quality of finishing pigs. The meta-analysis provided an opportunity to determine the consensus of previously published literature. Ten studies were evaluated to determine cutting yields and 8 studies were used to determine belly quality in this review. Pooled dietary RAC concentrations (5 mg/kg, 7.4 mg/kg, 10 mg/kg, and step-up feeding programs) and pooled feeding durations (up to 35 d before harvest) were compared with pigs not fed RAC (controls) and were analyzed as a meta-analysis using the mixed procedure of SAS. Ractopamine inclusion was the fixed effect in the model and the individual study was considered a random variable. The only difference between RAC and control pigs for whole primals as a percentage of side weight was the whole ham (P < 0.01). No other differences were detected for whole primals as a percentage of side weight. Yet, differences were detected in the standardized trimmed primal yields. A difference (P < 0.05) in percentages of the side weight was detected for the Boston butt, trimmed loin, and trimmed ham. This translated into RAC pigs having a carcass cutting yield (74.70% vs. 73.69%, respectively; P = 0.02; SED = 0.33) advantage of 1.01% units and a bone in lean cutting yield (61.43% vs. 60.33%, respectively; P = 0.03; SED = 0.40) advantage of 1.10% units when compared with control pigs. The advantage in bone-in cutability was a result of increased boneless sub primal yields in each of the lean cuts (shoulder, loin, and ham). When further evaluated, RAC pigs had a boneless shoulder (Boston butt + picnic) yield advantage of 0.32% units (P < 0.01; SED = 0.11), a 0.43% unit (P = 0.01; SED = 0.13) yield advantage in the boneless loin (Canadian back + tenderloin + sirloin), and a 0.51% unit (P < 0.001; SED = 0.11) advantage in the boneless ham (inside + outside + knuckle). A boneless yield was calculated using a summation of the percentage of side weight from the boneless shoulder, boneless loin, and boneless ham, which resulted in a 1.08% unit (36.28% vs. 35.20%, respectively; P = 0.002; SED = 0.25) advantage of RAC pigs when compared with control pigs. There were no subprimal yield differences (P = 0.93) in the trimmed belly between RAC pigs (12.18%) and control pigs (12.18%). However, RAC pigs (15.27 cm; 73.42) had narrower flop distances (P = 0.02; SED = 0.62) and greater iodine values (P = 0.01; SED = 0.33), respectively, when compared with control pigs (17.08 cm; 71.48).

Objectives were to test the effect of a low-sodium curing solution on processing characteristics of hams from purebred Berkshire pigs that were fed a step-up ractopamine HCl (RAC) feeding program or a negative control diet. Sixty pairs (n=120) of hams were selected from two blocks of purebred Berkshire pigs (n=200) that were fed either a control diet or 7.4 mg of ractopamine/kg of diet for 14 d followed by 10.0 mg of ractopamine/kg of diet for the last 14 d before slaughter. Three-piece, section-formed hams were cured with a standard (1.98% NaCl; REG) curing solution or a low-sodium with KCl replacement (0.67% NaCl and 1.29% KCl; LOW) curing solution. Pigs fed RAC had 3.18% greater BW, 11.90% greater ADG, and 10.34% greater G:F compared with control pigs. No differences (P≥0.07) were detected for the effect of diet, curing solution, or the interaction between diet and curing solution for ham weights, pump uptake, or cook yield [(cooked weight/green weight) 100]. Break strength (an indication of protein interaction and bind strength; 5.97 vs. 6.99 kg) and protein fat-free values (24.58 vs. 25.98%) were less (P≤0.05) in hams cured with LOW curing solution compared with hams cured with REG curing solution. Lightness (L*) and yellowness (b*) values were greater (P≤0.03), while redness (a*) values were less (P<0.01) in hams cured with LOW curing solution compared with hams cured with REG curing solution. A trained sensory panel detected less (P=0.03) flavor intensity in hams cured with LOW curing solution compared with hams cured with REG curing solution. Yet, no differences (P≥0.55) were detected between hams cured with LOW or REG curing solution for saltiness. Overall acceptability of hams cured with LOW curing solution tended to be less (P=0.09) compared with hams cured with REG curing solution; however, the magnitude of this difference was 0.34 on a 1 to 9 scale. Hams cured with LOW curing solution made hams paler and contain less intense flavor compared with hams cured with REG curing solution, but this was a justifiable way to lower sodium content by 64% units (1.44 vs. 4.04% Na) without detrimental processing or sensory effects.

The objectives were to compare slice characteristics and sensory attributes of bacon from immunologically castrated (IC) barrows with bacon from other sexes using a trained sensory panel. Bacon was obtained for sensory evaluation from 3 experiments. In Exp. 1, trimmed and squared bellies (n=180) of IC barrows, IC barrows fed ractopamine hydrochloride (IC+RAC), physically castrated (PC) barrows, intact males (IM), and gilts were used. Data were analyzed as a general linear mixed model and pen (n=48) served as the experimental unit. Treatment (sex or diet) was a fixed effect in all 3 experiments. In Exp. 2, untrimmed, natural fall bellies (n=96) from IC and PC barrows fed 0 or 30% or a withdrawal distillers dried grains with solubles (DDGS) program when slaughtered at 5 wk after the second dose (25 wk of age) were used. In Exp. 3, untrimmed, natural fall bellies (n=96) from IC and PC barrows fed the same experimental diets as in experiment 2 but slaughtered at 7 wk after the second dose (27 wk of age) were used. Data from Exp. 2 and 3 were analyzed as a 2×3 factorial arrangement in a randomized complete block design and pen was the experimental unit. Bellies from all 3 experiments were processed using the same protocols. In Exp. 1, IM had the greatest (P<0.0001) boar aroma and flavor scores among all treatments. No differences were detected among the other treatment groups for boar aroma or flavor. Intact males had the least (P<0.0001) desirable cured bacon aroma and flavor among all treatments. No differences were detected among the other treatment groups for bacon aroma or flavor. There were no differences in bacon aroma or off-flavor between IC and PC barrows slaughtered at 5 wk after the second dose regardless of DDGS feeding program. Bacon from PC barrows was saltier (P<0.01) than bacon from IC barrows when slaughtered at 5 wk after the second dose. There were no differences in bacon aroma, off-aroma, bacon flavor, or saltiness between IC and PC barrows slaughtered at 7 wk after the second dose regardless of DDGS feeding program. Total slice area of bacon slices from IC barrows slaughtered at 5 wk after the second dose were less (P<0.01) than PC barrows, but the differences diminished (P=0.16) when slaughtered at 7 wk after the second dose. Overall, panelists successfully detected boar odor and flavor in Exp. 1. Immunological castration was as effective as physical castration at eliminating boar aroma and boar flavor in bacon even when feeding differing DDGS feeding programs or when slaughtered at 5 or 7 wk after the second dose.