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The National Beef Quality Audit - 2022 serves as a benchmark of the current fed steer and heifer population of the U.S. beef industry and allows comparison to previous audits as a method of monitoring industry progress. In-plant cooler assessments and collections of beef carcass data took place from July 2021 to November 2022. During in-plant evaluations, 10% of 1-d production was surveyed for quality and yield indicating characteristics of fed beef carcasses ( n =  9,746 beef carcasses). Distributions of sex classes among sampled carcasses were steer (65.0%) and heifer (35.0%), whereas distributions of breed type were native (87.7%), dairy (11.3%), and Bos indicus (0.9%). Mean values were observed for USDA Yield Grades ( YG ; 3.3), USDA Quality Grade ( QG ; Choice 16 ), marbling score (Small 98 ), ribeye area (91.0 cm 2 ), adjusted fat thickness (1.49 cm), hot carcass weight (401.9 kg), and KPH (2.5%). Mean overall maturity was A 66 , with a mean lean maturity of A 56 and mean skeletal maturity of A 72 . There were 28.1% of carcasses identified for use in a USDA-certified beef G-Schedule Program. Defects, such as dark cutting and blood splash, were observed at 1.8% and 0.5%, respectively. Distributions of USDA YG were YG 1 (8.2%), YG 2 (30.7%), YG 3 (40.2%), YG 4 (16.6%), and YG 5 (4.3%). USDA QGs were observed at 7.5% Prime, 69.2% Choice, 16.4% Select, and 6.8% other. The results of this study provide an updated look at the current grading trends of beef carcasses in the United States to drive progress in the fed beef industry., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Supplemental methionine (Met) is widely used within the swine industry; however, data are limited regarding the effect of Met sources on carcass cutability and meat quality. The objective was to determine the effects of L-Met (LM, 99%), DL-Met (DLM, 99%), or calcium salt of DL-Met hydroxyl analog (MHA, 84%) in finishing pig diets on carcass characteristics and meat quality. At 9 weeks of age, pigs ( N  = 240) were allocated to 60 single-sex pens for a four-phase finishing trial that lasted 104 d. Pigs were fed a common grower diet until day 56 where pens were randomly allotted to one of the three experimental diets. For the remaining 7 wk of the finisher phase, pigs (BW = 79.9 ± 0.80 kg) were fed diets containing LM, DLM, or MHA, with the supplemental Met source providing 25% of standardized ileal digestible (SID) Met + cysteine (Cys) requirement based on 65% bioefficacy for MHA in comparison with LM or DLM. One pig per pen was slaughtered at the study conclusion (on day 104), and the left sides of carcasses were fabricated into subprimal cuts to determine carcass-cutting yields. Loin quality including proximate composition and shear force were measured. Hot carcass weight was not different ( P  = 0.34) between treatments (LM 104.5 kg; DLM 103.0 kg; MHA 101.5 kg), moreover, loin eye area was not different ( P  = 0.98) between treatments (LM 52.65 cm²; DLM 52.49 cm²; MHA 52.81 cm²). Boneless carcass-cutting yield was not different ( P  = 0.56) between treatments (LM 54.97 kg; DLM 54.82 kg; MHA 54.52 kg). Loin pH was not different ( P  = 0.24) between treatments (LM 5.45; DLM 5.48; MHA 5.45). However, drip loss tended to be reduced ( P  = 0.11) by the DLM treatment (5.58%) compared with LM (7.03%) and MHA (6.68%) treatments. Shear force was not different ( P  = 0.85) between treatments (LM 3.03 kg; DLM 3.06 kg; MHA 3.10 kg). However, cook loss tended to be reduced ( P  = 0.06) by the DLM treatment (16.20%) compared with LM (18.18%) and MHA (18.50%) treatments. These data suggest that only minimal differences in carcass cutability and meat quality can be attributed to Met source in finishing pig diets when using 65% bioefficacy for MHA relative to L-Met or DL-Met., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

Broilers are commonly exposed to coccidiosis infections, and the use of dietary strategies to reduce losses in growth performance has practical implications for the poultry industry. Methionine (Met) is typically the first limiting amino acid for broilers and is involved in metabolic and immunological pathways; however, literature is conflicting on how dietary Met requirements are affected by environmental stressors. Our objective was to assess how the Met requirement changes during coccidiosis based on results of growth performance, carcass traits, and health outcomes. Two trials were conducted using 780 male Ross 308 broiler chicks in floor pens randomly assigned to 1 of 12 experimental treatments. All birds received common starter (d 0-10) and finisher (d 24-35, Trial 2 only) diets, and only differed based on their assigned experimental grower diet (d 10-24). Trial 1 experimental grower diets ranged from 2.61 to 6.21 g/kg digestible Met. Trial 2 experimental grower diets were formulated to contain 15% below, at, or 15% above the Met requirement determined in Trial 1. Birds were exposed to a coccidiosis challenge on d 11, with blood and tissue collection (1 bird/pen) on d 18 and carcass processing on d 35 (2 birds/pen) in Trial 2. Data were analyzed using a 1- or 2-way ANOVA. A non-linear regression analysis was conducted in Trial 1 to determine the Met requirement of 4.32 g of digestible Met/kg of diet using BW gain. Coccidiosis infection reduced (P < 0.05) growth performance during the experimental grower and overall study periods in Trial 2. Increasing dietary Met from below requirement to meeting requirement during the grower period improved (P < 0.001) BW gain and feed conversion ratio (FCR), but this effect was only significant between treatments below and above the requirement for the overall study period. There was an interactive effect (P = 0.038) on FCR for the overall study period. These findings provide evidence that the Met requirement is likely increased during coccidiosis based on growth performance outcomes., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The National Beef Quality Audit (NBQA)-2022 serves as a benchmark of the current market cow and bull sectors of the U.S. beef industry and allows comparison to previous audits as a method of monitoring industry progress. From September 2021 through May 2022, livestock trailers ( n  = 125), live animals ( n  = 5,430), and post-slaughter hide-on animals ( n  = 6,674) were surveyed at 20 commercial beef processing facilities across the U.S. Cattle were transported in a variety of trailer types for an average distance of 490.6 km and a mean transport time of 6.3 h. During transit, cattle averaged 2.3 m 2 of trailer space per animal indicating sufficient space was provided according to industry guidelines. Of all trailers surveyed, 55.3% transported cattle from an auction barn to a processing facility. When surveyed, 63.6% of all truck drivers reported to be Beef Quality Assurance certified. The majority (77.0%) of cattle were sound when evaluated for mobility. Mean body condition scores (9-point scale) for beef cows and bulls were 3.8 and 4.4, respectively, whereas mean body condition scores (5-point scale) for dairy cows and bulls were 2.3 and 2.6, respectively. Of the cattle surveyed, 45.1% had no visible live animal defects, and 37.9% had only a single defect. Of defects present in cows, 64.6% were attributed to an udder problem. Full udders were observed in 47.5% of all cows. Nearly all cattle were free of visible abscesses and knots (97.9% and 98.2%, respectively). No horns were observed in 89.4% of all cattle surveyed. Beef cattle were predominantly black-hided (68.9% and 67.4% of cows and bulls, respectively). Holstein was the predominant dairy animal observed and accounted for 85.7% of the cows and 98.0% of the bulls. Only 3.1% of all animals had no form of identification. Findings from the NBQA-2022 show improvements within the industry and identify areas that require continued education and research to improve market cow and bull welfare and beef quality., Competing Interests: There are no known conflicts of interest by any of the authors., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The objective of this research was to determine the effects of mid-gestational maternal inflammation on performance, carcass characteristics, and meat quality of offspring. Pregnant gilts were administered either lipopolysaccharide (LPS; n = 7) or saline (CON, n = 7) from days 70 to 84 of gestation. Gilts assigned to the LPS treatment were administered an intravenous injection of reconstituted LPS every other day with a beginning dose of 10 μg LPS/kg body weight and subsequent doses increasing by 12%, while CON gilts received intravenous injections of comparable volumes of saline. Gilts farrowed naturally, and at day 66 of age, a total of 59 pigs, both barrows and gilts began a 3-phase feeding regimen designed to meet or exceed nutrient requirements for growing-finishing pigs. Pigs were weighed on days 0, 35, 70, and 105 of the finishing trial to determine average daily gain, average daily feed intake, and gain-to-feed ratio (G:F). On day 106, pigs were slaughtered under the supervision of the U.S. Department of Agriculture Food Safety Inspection Service. Ending live weight, hot carcass weight, and dressing percentage were determined. The left side of carcasses was weighed and fabricated to determine carcass cutting yields. The semitendinosus was collected for histological samples. Fresh belly characteristics and loin quality were measured. Two chops were collected for Warner-Bratzler shear force and proximate analysis. No differences (P ≥ 0.13) between LPS and CON pigs were observed for growth performance in phases 1, 2, 3, or overall (days 0 to 105) performance with the exception of overall G:F reduced in CON pigs compared with LPS pigs (P = 0.03). There was a tendency for carcass yield to be reduced (P = 0.06; 0.82% units) in LPS pigs compared with CON pigs. Additionally, longissimus muscle area tended to be reduced (P = 0.10) 2.27 cm2 in LPS compared with CON pigs. Loin chop quality traits including instrumental color, subjective color, marbling, firmness, pH, and drip loss were not different (P ≥ 0.09) between LPS and CON pigs. Fresh belly characteristics were not different (P ≥ 0.22) between LPS and CON pigs. There were no differences in primal and subprimal weights, except that LPS pigs tended to have a reduction (P ≥ 0.07) in tenderloin and Canadian back weights compared with CON pigs. Furthermore, LPS pigs had no differences (P ≥ 0.25) in muscle fiber composition or size; however, LPS pigs tended (P = 0.10) to have a 13% reduction in estimated muscle fibers number compared with CON pigs. In summary, mid-gestational inflammation did not result in reduced meat quality, growth performance, or carcass yields of offspring., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The many possible treatments and continuously changing consumer trends present a challenge when selecting antimicrobial interventions during pork processing. Thirty-five potential antimicrobials were screened at commercial working concentrations by individually adding them to miniaturized (69 cm 3 ) disks of pork loin ends, followed by inoculation with Salmonella Typhimurium ATCC 19585. Two organic acids and nine essential oils significantly inhibited Salmonella counts on pork ( p < 0.05). However, six compounds that represent different levels of significance ( p < 0.05- p < 0.0001) were selected as independent variables to build a Response Surface Methodology model based on a Doehlert matrix (Doehlert Matrix-RSM): lactic acid 1.25%, formic acid 0.25%, cumin 0.25%, clove 0.25%, peppermint 0.5%, and spearmint 0.5%. The goal of the Doehlert Matrix-RSM was to study single and paired effects of these antimicrobials on the change in Salmonella over 24 h. The Doehlert Matrix-RSM model predicted that lactic acid, formic acid, cumin, peppermint, and spearmint significantly reduced Salmonella when added alone, while no significant interactions between these antimicrobials were found. A laboratory-scale validation was carried out on pork loin end slices, which confirmed the results predicted by the model. While this screening did not identify novel synergistic combinations, our approach to screening a variety of chemical compounds by implementing a miniaturized pork loin disk model allowed us to identify the most promising antimicrobial candidates to then formally design experiments to study potential interactions with other antimicrobials.

Feeding growing-finishing pigs supplemental fat is a common practice in the swine industry and can result in improved feed efficiency and reduced feed intake; however, dietary lipids also play a key role in determining pork quality. Objectives of the study were to evaluate the effects of feeding graded levels of high oleic soybean oil (HOSO) on loin and belly quality. A total of 288 pig raised in two separate blocks (144 pigs each) were assigned to one of four diets containing either 25% dried distiller's grains with solubles (DDGS), 2% high oleic soybean oil (HOSO2), 4% high oleic soybean oil (HOSO4), or 6% high oleic soybean oil (HOSO6). Following the conclusion of the feeding trial, 144 pigs were slaughtered at the University of Illinois Meat Science Laboratory. Following fabrication, loins were collected for the evaluation of fresh quality measurements and color stability. Belly quality and fatty acid composition were evaluated using skin-on natural fall bellies. There were no differences (P ≥ 0.11) in pH, visual color, lightness (L*), drip loss, or WBSF among dietary treatments. However, visual marbling was increased (P ≤ 0.01) in loin chops from pigs fed HOSO4 and HOSO6 treatments compared with chops from pigs fed the DDGS dietary treatment. Additionally, loin chops were more red (a*) (P ≤ 0.01) from pigs fed HOSO diets when compared with pigs fed DDGS. Extractable lipid was decreased (P ≤ 0.01) in fresh loin chops from pigs fed DDGS and HOSO2 diets compared with pigs fed HOSO6. There were no differences (P ≥ 0.75) in trained sensory tenderness, juiciness, or flavor for loin chops from pigs fed different dietary treatments. Pork fatty acid composition was altered by dietary HOSO inclusion, with pigs fed DDGS having (P ≤ 0.01) the greatest concentration of C16:0 and was decreased with increasing levels of HOSO inclusion. Inversely, the percentage of C18:1n-9 was least (P ≤ 0.01) in pigs fed DDGS and increased with increasing levels of HOSO inclusion. Pigs fed DDGS produced wider (P ≤ 0.03) and thinner (P ≤ 0.04) bellies with reduced flop distance compared with pigs fed HOSO diets. Overall, HOSO diets did not negatively affect fresh loin quality or sensory traits of loin chops. Furthermore, feeding HOSO to swine resulted in bellies containing greater percentages of oleic acid and reduced percentages of palmitic and linoleic acid., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Pork hot carcass weights (HCW) have been increasing 0.6 kg per year, and if they continue to increase at this rate, they are projected to reach an average weight of 118 kg by the year 2050. This projection in weight is a concern for pork packers and processors given the challenges in product quality from heavier carcasses of broiler chickens. However, previous work demonstrated that pork chops from heavier carcasses were more tender than those from lighter carcasses. Therefore, the objective was to determine the effects of pork hot carcass weights, ranging from 90 to 145 kg with an average of 119 kg, on slice shear force and sensory traits of Longissimus dorsi chops when cooked to 63 or 71 °C, and to assess if differences in chilling rate can explain differences in sensory traits. Carcasses were categorized retrospectively into fast, medium, or slow chilling-rates based on their chilling rate during the first 17 h postmortem. Loin chops cut from 95 boneless loins were cooked to either 63 or 71 °C and evaluated for slice shear force and trained sensory panel traits (tenderness, juiciness, and flavor) using two different research laboratories. Slopes of regression lines and coefficients of determination between HCW and sensory traits were calculated using the REG procedure in SAS and considered different from 0 at P ≤ 0.05. As hot carcass weight increased, chops became more tender as evidenced by a decrease in SSF (63 °C β = -0.0412, P = 0.01; 71 °C β = -0.1005, P < 0.001). Furthermore, HCW explained 25% (R2 = 0.2536) of the variation in chilling rate during the first 5 h of chilling and 32% (R2 = 0.3205) of the variation in chilling rate from 5 to 13 h postmortem. Slow- and medium-rate chilling carcasses were approximately 12 kg heavier (P < 0.05) than fast chilling carcasses. Slice shear force of chops cooked to 63 and 71 °C was reduced in slow and medium chilling compared with fast chilling carcasses. Carcass temperature at 5 h postmortem explained the greatest portion of variation (R2 = 0.071) in slice shear force of chops cooked to 63 °C. These results suggest that carcasses tend to chill slower as weight increases, which resulted in slight improvements in sensory traits of boneless pork chops regardless of final degree of doneness cooking temperature., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Feeding growing-finishing pigs supplemental fat is a common practice in the swine industry and can result in improved feed efficiency and reduced feed intake; however, dietary lipids also play a key role in determining pork composition. The objectives of the current study were to evaluate the effects of feeding graded levels of high oleic soybean oil (HOSO) on growth performance and carcass characteristics. A total of 288 pigs raised in two separate blocks (144 pigs each) were assigned to one of four diets containing either 25% dried distiller's grains with solubles (DDGS), 2% high oleic soybean oil (HOSO2), 4% high oleic soybean oil (HOSO4), or 6% high oleic soybean oil (HOSO6). Pigs were housed 4 per pen and fed for 98 d using a 3-phase feeding system. Pigs were individually weighed and feed intake was recorded throughout the trial to calculate average daily feed intake (ADFI) and gain to feed ratio (G:F). A total of 144 pigs were transported to the University of Illinois Meat Science Laboratory and fabricated into primal and subprimal cuts to calculate carcass cutting yields. Differences in growth performance were observed, with pigs fed the DDGS treatment exhibiting greater (P ≤ 0.01) overall ADFI consuming 0.21, 0.18, and 0.28 kg/d more than HOSO2, HOSO4, and HOSO6 diets, respectively. Pigs fed the HOSO6 diet had greater (P ≤ 0.03) overall G:F than pigs fed DDGS and HOSO2 diets but did not differ (P = 0.12) from pigs fed HOSO4. Furthermore, differences in carcass traits were observed. Hot carcass weight was increased (P ≤ 0.03) in pigs fed the HOSO6 diet compared with pigs fed the DDGS and HOSO2 diets, while pigs fed HOSO4 did not differ (P > 0.05) from either extreme. Additionally, pigs fed HOSO4 and HOSO6 produced fatter (P ≤ 0.01) carcasses with reduced (P ≤ 0.01) standardized fat-free lean. Minimal differences were observed in primal weights expressed as a percentage of chilled side including bone-in Boston butt, trimmed loin, and trimmed ham with primal weights decreasing with increasing inclusion of dietary HOSO. Overall, pigs fed HOSO2 had reduced ADFI with similar backfat thickness and standardized fat-free lean compared with pigs fed the DDGS treatment. However, pigs fed HOSO 4% and 6% not only had improvements in ADFI and G:F but also had increased backfat thickness, which resulted in reductions in standardized fat-free lean and primal weights expressed as a percentage of chilled side weight., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The objective was to test inherent cooking rate differences on tenderness values of boneless pork chops when exogenous factors known to influence cooking rate were controlled. Temperature and elapsed time were monitored during cooking for all chops. Cooking rate was calculated as the change in °C per minute of cooking time. Warner-Bratzler shear force (WBSF) was measured on chops cooked to either 63 °C or 71 °C. Slopes of regression lines and coefficients of determination between cooking rate and tenderness values for both degrees of doneness (DoD) were calculated. Shear force values decreased as cooking rate increased regardless of DoD ( p ≤ 0.05), however changes in tenderness due to increased cooking rate were limited (β1 = -0.201 for 63 °C; β1 = -0.217 for 71 °C). Cooking rate only explained 3.2% and 5.4% of variability in WBSF of chops cooked to 63 °C and 71 °C, respectively. Cooking loss explained the most variability in WBSF regardless of DoD (partial R 2 = 0.09-0.12). When all factors were considered, a stepwise regression model explained 20% of WBSF variability of chops cooked to 63 °C and was moderately predictive of WBSF (model R 2 = 0.34) for chops cooked to 71 °C. Overall, cooking rate had minimal effect on pork chop tenderness.

It was hypothesized that hybrid rye may replace corn in diets for growing and finishing pigs without impacting growth performance, carcass characteristics, or meat quality. A total of 128 pigs (23.69 ± 2.51 kg) were allotted to four treatments with eight replicate pens per treatment. Phases 1 and 2 diets were fed for 35 d each and phase 3 diets were fed for 27 d. Within each phase, pigs were fed a control corn and soybean meal diet or a diet in which 33%, 66%, or 100% of the corn in the control diet was replaced with hybrid rye. Average daily gain (ADG) and average daily feed intake (ADFI) decreased (linear, P < 0.05) in phase 1 with increased dietary inclusion of hybrid rye. In phase 3, gain:feed (G:F) increased and then decreased (quadratic, P < 0.05) with more hybrid rye in the diet. Overall ADG, ADFI, and G:F did not differ among treatments. Diet did not impact most carcass traits, but loin (visual) and backfat (instrumental L*) color were paler (linear, P < 0.05) with greater inclusion of hybrid rye in the diet. Organ weights increased (linear, P < 0.05) with increased dietary hybrid rye. In conclusion, pigs fed hybrid rye consumed less feed in phase 1, resulting in reduced ADG, but growth performance for the entire growing-finishing period did not differ among treatments. Hybrid rye may replace all the corn in growing and finishing pig diets without diminishing growth performance or carcass quality, but feed intake may be reduced at high inclusion rates., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The objective was to quantify the effects of the beta-adrenergic agonist (β-AA) ractopamine hydrochloride (Actogain, Zoetis, Parsippany, NJ) on nitrogen excretion and nutrient digestibility in feedlot cattle. In experiment 1, 12 Simmental × Angus steers were blocked by bodyweight (531 ± 16 kg) and used in a randomized complete block design. Dietary treatments included: 1) a control without β-AA (CON) or 2) 400 mg/steer/d ractopamine hydrochloride (RAC) for 35 d before slaughter. Diets contained (DM basis) 55% dry-rolled corn, 20% corn silage, 15% modified wet distillers grains with soluble, and 10% supplement. For each block, total collection of feed, orts, feces, and urine were conducted for two 5 d sampling periods during week 2 and 4 of RAC supplementation. No interaction ( P > 0.21) between treatment and collection period was observed for any parameter evaluated. Dietary treatment had no effect ( P = 0.51) on DMI, but RAC had decreased fecal DM output ( P = 0.04) compared with CON. Thus, RAC had greater apparent total tract DM digestibility (77.2 vs. 73.5%; P < 0.01), N digestibility (72.4 vs. 69.4%; P = 0.01), and NDF digestibility (65.6 vs. 60.2%; P < 0.01) than CON. Although treatment did not affect nitrogen intake ( P = 0.52), RAC tended to reduce total nitrogen excretion (113.3 vs. 126.7 g/d; P = 0.10) compared with CON due to a tendency for decreased fecal nitrogen output (53.9 vs. 61.3 g/d; P = 0.10). However, dietary treatment had no effect ( P = 0.53) on urinary nitrogen output or percentage of urinary nitrogen excreted as urea ( P = 0.28). Experiment 2 was an in vitro experiment conducted to validate the effects of RAC on nutrient digestibility using Simmental × Angus heifers (451 ± 50 kg). Rumen fluid was collected individually by stomach tube from CON- ( n = 9) and RAC-fed ( n = 10) heifers to inoculate bottles containing a CON or RAC-containing substrate in a split-plot design. No interaction between rumen fluid source and in vitro substrate was observed. Greater IVDMD ( P = 0.01) was observed in rumen fluid from RAC-fed heifers compared with rumen fluid from CON-fed heifers. The inclusion of RAC in the in vitro substrate increased IVDMD ( P < 0.01). Overall, feeding RAC increased microbial digestion of the dry-rolled corn-based finishing diet to increase total tract dry mater digestion by 5% and reduce nitrogen excretion by 10.6% in the 35 d period prior to slaughter., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The objective was to determine the change in extractable lipid concentration during cooking of boneless pork chops to different endpoint temperatures. Pork loins (152 total) were used and three consecutive chops were cut from each loin. Chop 1 was evaluated raw (not cooked) for intramuscular fat (IMF) percentage. Raw IMF percentages were used to categorize the remaining two chops, from each loin, into low, average, and high marbling bins. The low bin included ≤3% IMF, the average bin included 3-4% IMF, and the high bin included ≥4% IMF. Chop 2 was cooked to 63 °C and chop 3 was cooked to 71 °C to evaluate cook loss, Warner-Bratzler shear force (WBSF), and IMF percentage. When cooked to either 63 or 71 °C, high IMF chops maintained greater ( P < 0.001) IMF percentage than average and low IMF chops. Additionally, average IMF chops maintained greater ( P < 0.001) IMF percentage than low chops, regardless of endpoint cooking temperature. The three marbling categories did not differ in cook loss ( P = 0.28) or WBSF ( P = 0.23) when chops were cooked to either 63 or 71 °C. However, both WBSF (2.76 kg) and cook loss (18.72%) were decreased ( P < 0.001) in chops cooked to 63 °C compared with chops cooked to 71 °C (3.08 kg, 23.45%). Overall, differences in IMF percentages persisted even after cooking. Furthermore, IMF percentage of pork chops did not affect tenderness., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

A total of 976 pigs (PIC 327 × Camborough; PIC, Hendersonville, TN; initially 22.0 ± 1.53 kg body weight [BW]) were used in a 160-d growth study to evaluate the effects of increasing space allowance and varying marketing strategies on growth performance of pigs raised to market weights of ~165 kg. Pens of pigs were blocked by location within the barn and allotted to one of six treatments. Pen served as the experimental unit, and there were eight replicate pens per treatment. The first four treatments consisted of increased initial stocking density and did not utilize topping strategies: (1) 14 pigs/pen (1.17 m 2 /pig), (2) 17 pigs/pen (0.97 m 2 /pig), (3) 20 pigs/pen (0.82 m 2 /pig), and (4) 23 pigs/pen (0.71 m 2 /pig). The fifth treatment began with 25 pigs/pen (0.66 m 2 /pig) and had four marketing events with the heaviest 3 pigs/pen removed on day 93, and additional pigs removed to a common inventory of 20 pigs/pen on day 122 and 17 pigs/pen on day 147 with final marketing on day 160. The final treatment began the experiment with 23 pigs/pen (0.71 m 2 /pig) with three marketing events to achieve a common inventory of 20 pigs/pen on day 108 and 17 pigs/pen on day 147. Pens of pigs were weighed and feed disappearance measured on days 0, 55, 93, 108, 122, 135, 147, and 160. As space allowance decreased from 1.17 to 0.71 m 2 /pig via increased initial pen inventory (treatments 1 to 4), overall average daily gain (ADG) and average daily feed intake (ADFI) decreased (linear, P < 0.001), while gain:feed ratio (G:F) did not differ ( P > 0.05). The treatments with multiple marketing events were compared with each other and with the treatment that began with 0.71 m 2 /pig and only marketed once at the end of the study. Overall ADG and ADFI were not different ( P > 0.05) among these three treatments. Marketing pigs three or four times improved ( P < 0.05) G:F compared with the treatment that began the study with 0.71 m 2 /pig and marketed only once. Reducing floor space allowance for heavy weight pigs decreased intake, which resulted in lower growth rate and final BW, with these reductions occurring before the critical k -value was reached. Total weight gain per pen was maximized with the lowest space allowance and the multiple marketing treatments. Thus, strategic use of pig removals prior to final marketing may allow producers to maximize both number of pigs and total weight marketed through a barn when feeding to heavy weights., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science.)

The objective was to control intrinsic and extrinsic factors associated with the production and slaughter of pigs to determine effects of sire line (Pietrain vs. Duroc ancestry) on growth performance, carcass and belly characteristics, and commercial bacon yields of growing-finishing pigs. There were no differences in growth performance (P ≥ 0.08) or belly processing characteristics (P ≥ 0.09). Pietrain sired pigs had a greater lean yield (P ≤ 0.01). Duroc sired pigs had darker, more highly marbled loins (P ≤ 0.04) and thicker bellies (P < 0.001). Bacon from Pietrain sired pigs had a greater (P = 0.04) lean to fat ratio with 1.58% increase (P = 0.04) in average bacon slice lean. Barrows had more highly marbled loins (P ≤ 0.01) and thicker bellies (P < 0.001) than gilts. Bacon from barrows had a greater slice area (P < 0.001) while bacon from gilts had a greater lean to fat ratio (P = 0.04)., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Today, the United States exports 2.2 million tons of pork and pork products annually, representing just over 26% of U.S. pork production. In order to meet specific demands of a growing export market, pork quality and carcass characteristics are now integrated into breeding objectives. Color and marbling are 2 loin quality traits that influence consumer acceptability of pork and while correlations between early and aged ventral quality have been established, it is unclear if those correlations differ between production objectives (meat quality vs. lean growth). Therefore, the objective of this experiment was to compare correlations among early postmortem ventral loin quality characteristics and aged ventral loin and chop quality characteristics between pigs sired by either Pietrain (lean growth) or Duroc (meat quality) boars. Early postmortem (~1 d) quality traits included: instrumental and visual color, marbling and firmness, and loin pH on the ventral surface of the loin. Loins were aged until 14 d postmortem in vacuum packages. Aged quality traits included traits evaluated early as well as Warner-Bratzler shear force (WBSF) and cook loss. Correlations were compared between Pietrain and Duroc-sired pigs using a Fisher's z-test. Early instrumental lightness (L*) was moderately correlated with aged ventral L* (Pietrain r = 0.47; Duroc r = 0.65) and aged ventral visual color (Pietrain r = 0.42; Duroc r = 0.58). Early ventral visual color was moderately correlated with aged chop L* (Pietrain r = 0.46; Duroc r = 0.60) and aged chop visual color (Pietrain r = 0.45; Duroc r = 0.57). Early visual marbling was strongly correlated (Pietrain r = 0.68; Duroc r = 0.84) with aged chop visual marbling. Within the Duroc-sired pigs, early L* was moderately correlated with aged chop L* (r = 0.64) but only weakly correlated (r = 0.35) within the Pietrain-sired pigs and those correlations differed at P ≤0.02. Within the Duroc-sired pigs, early ventral visual color was moderately correlated with aged pH (r = 0.44) and aged ventral L* (r = 0.57) but only weakly correlated (r ≤ 0.29) within the Pietrain-sired pigs and those correlations differed at P ≤0.03. No early postmortem quality traits were correlated (|r| ≤ 0.34) with WBSF or cook loss for either sire line. In summary, correlations between early and aged postmortem quality traits rarely differed between Duroc- and Pietrain-sired pigs. It is not necessary to account for sire line when relating early and aged quality characteristics.

Meta-analyses techniques using 11 independent datasets were used to determine correlations between pork loin quality evaluated at 1-d postmortem and quality evaluated at 12- to 28-d postmortem. Datasets encompassed approximately 3,957 loins. The effects of aging on ventral loin surface quality were determined using a paired-T test. Ventral loin surfaces become 8% lighter (P < 0.0001), 44.5% redder (P < 0.0001), and 46% more yellow (P < 0.0001) during the aging period. Therefore, it is apparent that loin quality changes during postmortem aging. Because of this, it becomes necessary to determine the correlation between early and aged pork quality parameters. Pearson correlation coefficients within original datasets were calculated, and then sample-weighted mean correlations r¯ and variances [Var(r)] were calculated across datasets. Early postmortem ventral instrumental lightness (L*) was moderately correlated with aged ventral L* r¯ = 0.50), aged ventral visual color r¯ = -0.38), aged chop face (freshly cut) L* r¯ = 0.44), and aged chop face visual color r¯ = -0.38). Early postmortem ventral instrumental redness (a*) was moderately correlated with aged ventral a* r¯ = 0.49) and aged chop face a* r¯ = 0.46). Early postmortem ventral visual color was moderately correlated with aged ventral L* r¯ = -0.51), aged ventral color (r¯ = 0.50), aged chop face L* r¯ = -0.43), and aged chop face visual color r¯ = 0.43). However, no instrumental or visual color parameters were moderately or strongly correlated with instrumental tenderness or sensory panel ratings of tenderness and juiciness (|r¯| ≤ 0.36). Early postmortem ventral visual marbling was moderately correlated with aged ventral marbling r¯ = 0.63) and aged chop face visual marbling r¯ = 0.56). Visual marbling was not (|r¯| ≤ 0.12) correlated with instrumental tenderness or sensory panel ratings of tenderness and juiciness. Stepwise regression, using a holo-analysis approach, was used to determine the predictive ability of early postmortem ventral color, marbling, firmness, and pH on sensory panels ratings of tenderness (R2 = 0.13), juiciness (R2 = 0.09), and flavor (R2 = 0.28). Early postmortem color and marbling are important pork quality traits in consumers purchasing decisions, but are poorly related to traits associated with eating experience. Still, they may be predicative of traits associated with purchasing intent.

The objective was to evaluate the interaction of a trace mineral (TM) injection (Multimin 90) and a supranutritional concentration of dietary vitamin E (VITE) on performance, carcass characteristics, and color stability of strip steaks from feedlot heifers. Prior to trial initiation, Angus × Simmental cross heifers (N = 48) were managed on a common diet supplemented to meet the NRC recommendations. Heifers were stratified by BW and allotted to a 2 × 2 factorial arrangement: 1) no supplemental vitamin E and saline injection (CONT + SAL), 2) 1,000 IU vitamin E·heifer-1·d-1 and saline injection (VITE + SAL), 3) no supplemental vitamin E and TM injection (CONT + MM), or 4) vitamin E and TM injection (VITE + MM). Trace mineral injection contained 15, 10, 5, and 60 mg/mL of Cu, Mn, Se, and Zn, respectively, and TM injection or saline injection (1 mL/68 kg BW) were given on day 0 of the 89-d finishing period. All heifers were fed a common diet containing a basal concentration of 19.8 IU/kg DM vitamin E. Heifers were slaughtered and loins sections were collected. Strip steaks were cut and placed in overwrap trays for evaluation of color stability for 16 d. Data were analyzed using the MIXED procedure of SAS. Color stability data were analyzed as repeated measures. Neither TM injection nor VITE had an effect on final BW, DMI, or G:F (P ≥ 0.12). There was a tendency (P = 0.09) for TM injection to increase ADG. A tendency (P = 0.08) was observed for TM injection to increase DMI of heifers receiving supranutritional VITE. Trace mineral injection and VITE had no effect on HCW, yield grade, 12th-rib backfat thickness, or ribeye area (P ≥ 0.34). Marbling scores tended to increase (P = 0.08) in VITE heifers compared with control-fed heifers. Vitamin E supplementation decreased final lipid oxidation (1.00 vs. 1.97 µg malondialdehyde/g fat, P = 0.03) and total visual discoloration (15.82% vs. 33.96%, P = 0.04) of steaks compared with steaks from nonsupplemented heifers. Heifers fed supranutritional VITE produced steaks that maintained retail color longer shown by lower hue angle values (38.17° vs. 38.66°, P < 0.01) than nonsupplemented heifers. A TM injection × vitamin E × day interaction (P < 0.01) revealed by day 16 steaks from the CONT + MM heifers exhibited greater discoloration than VITE + SAL and VITE + MM steaks with CONT + SAL intermediate. Overall, VITE improved color stability and TM injection appeared to increase discoloration of strip steaks from feedlot heifers after day 14 of display.

The objective was to compare growth performance, belly characteristics, and bacon slicing yields of growing-finishing pigs fed a subtherapeutic dose of an antibiotic, a natural antimicrobial, or a diet containing no antibiotics or antimicrobials. Barrows and gilts (96 each, initial BW: 27.52±3.98kg) were housed in 48 pens (8 replications per treatment) in a 2×3 factorial randomized complete block design. Pens were assigned 1 of 3 diets: antibiotic free, oregano or tylosin phosphate. Pigs were slaughtered at an average BW of 127.31±10.18kg. There were no differences among dietary treatments for growth performance (P≥0.06), carcass cutability (P≥0.42), loin quality (P≥0.28), fresh belly dimensional characteristics (P≥0.11), IV (P≥0.87) or bacon processing characteristics (P≥0.07). Given the lack of differences in meat quality from pigs fed diets without antibiotics, the implementation of VFD in the United States should not result in changes in pork quality., (Copyright © 2017. Published by Elsevier Ltd.)

Rapid assessment of pork quality by packers necessitates using early postmortem (∼1 d) traits as an indication of aged pork quality (∼14 d). Efforts have been made to develop a grading system based on color and marbling of the ventral side of boneless loins. In order for this system to be successful, there must be a correlation between early postmortem quality traits observed by packers and the same traits observed by consumers after aging. However, the strength and direction of those correlations are unclear. It is also unknown if the correlations between early and aged postmortem quality differ between barrows (B) and gilts (G). Therefore, the objectives were to determine correlations between early postmortem loin quality characteristics and aged loin quality characteristics, and determine if those correlations differed between barrows and gilts. Early postmortem (∼1 d) quality traits included: instrumental and subjective color, marbling and firmness, and loin pH on the ventral surface of the loin. Loins were aged until 14 d postmortem in vacuum packages. Aged quality traits included traits evaluated early as well as shear force and cook loss. Correlations were compared between barrows and gilts using a Fisher's z test. Overall, early subjective firmness scores of barrows were greater ( P < 0.001) than those of gilts. No other early quality traits differed between sexes. Early pH was correlated with aged pH ( r = 0.80 B; 0.75 G), ventral lightness ( r = -0.57 B; -0.54 G), ventral yellowness ( r = -0.55 B; -0.55 G), subjective ventral color ( r = 0.55, B; 0.41 G), and subjective chop color ( r = 0.42 B; 0.44 G). Correlations of early pH and aged quality did not differ between sexes. Early lightness was correlated with aged ventral pH ( r = -0.56) and subjective color ( r = -0.39) in barrows but not gilts ( P ≤ 0.04). Early lightness was correlated with aged lightness ( r = 0.60 B; 0.51 G) and yellowness ( r = 0.49 B; 0.55 G), but was not correlated with to any aged chop quality traits. Early marbling was correlated with ventral color ( r = 0.42) in barrows and ventral marbling ( r = 0.67 B; 0.66 G) and chop marbling ( r = 0.57 B; 0.59 G) in barrows and gilts. In summary, early pH and lightness were correlated with aged quality characteristics and correlations rarely differed between barrows and gilts. Sex does not need to be accounted for when relating early and aged quality characteristics.

The objective was to determine the predictive abilities of HCW for loin, ham, and belly quality of 7,684 pigs with carcass weights ranging from 53.2 to 129.6 kg. Carcass composition, subjective loin quality, and ham face color were targeted on all carcasses, whereas in-plant instrumental loin color and belly quality were assessed on 52.0 and 47.5% of carcasses, respectively. Loin chop slice shear force (SSF), cured ham quality, and adipose iodine value (IV) were evaluated on at least 10% of the population. The slope of regression lines and coefficients of determination between HCW and quality traits were computed using PROC REG of SAS and considered significant at ≤ 0.05. As HCW increased, boneless loins became darker and redder, evidenced by lower L* (β = -0.0243, < 0.001) and greater a* values (β = 0.0106, < 0.001); however, HCW accounted for only ≤0.80% of the variability in loin L* and a* values. Similarly, subjective loin color score (β = 0.0024, < 0.001) increased with increasing carcass weight, but subjective marbling score was not affected by HCW (β = -0.0022, = 0.06). After 20 d of aging, HCW explained only 0.98% of the variability in loin L* values (β = -0.0287, < 0.01). Heavier carcasses had lower SSF values (β = -0.1269, < 0.001) of LM chops, although HCW explained only 4.46% of the variability in SSF. Although heavier carcasses produced loins that exhibited lower ultimate pH values (β = -0.0018, < 0.001), HCW explained only 1.23% of the variability in ultimate loin pH. Interestingly, cook loss decreased (β = -0.0521, < 0.001) as HCW increased, with HCW accounting for 5.60% of the variability in cook loss. Heavier carcasses resulted in darker, redder ham face color ( < 0.001), but HCW accounted for only ≤2.87% of the variability in ham face L* values and 0.47% of the variability in a* values. Heavier carcasses produced thicker and firmer bellies, with HCW accounting for 37.81% of the variability in belly thickness (β = 0.0272, < 0.001), 20.35% of the variability in subjective flop score (β = 0.0406, < 0.001), and 10.35% of the variability in IV (β = -0.1263, < 0.001). Overall, the proportion of variability in loin and ham quality explained by HCW was poor (≤5.60%), suggesting that HCW is a poor predictor of the primal quality of pigs within this weight range. Nonetheless, HCW was a moderate predictor of belly quality traits. The findings of this study suggest that increasing HCW did not compromise loin, ham, or belly quality attributes.

The objectives were to 1) assess cutability, quality, and value of carcasses from immunologically castrated (IC) barrows compared with carcasses from physically castrated (PC) barrows and 2) evaluate the effect of hot carcass weight (HCW) on cutability and value of IC barrows summarizing U.S. data. Lean cutting yield (LCY) was defined as: LCY = [(whole ham + trimmed loin + Boston butt + picnic + spareribs)/chilled side wt] x 100. Carcass cutting yield (CCY) was determined using the following equation: CCY = [(lean cutting yield components + natural fall belly)/chilled side wt] x 100. To evaluate the effects of HCW of IC barrows on carcass cutting yields, IC barrows were grouped by HCW: light ( < 90.9 kg), average (90.9-97.7 kg), or heavy ( > 97.7 kg). Differences in the value of the carcass components for IC and PC barrow carcasses were calculated using a 5 yr average of meat prices from the USDA Agriculture Marketing Service and the carcass cutting yield estimates generated from this summary. Data were analyzed using the MIXED procedure of SAS with fixed effects of Improvest treatment or HCW group. Study was included as a random effect. This review allowed for a summarization of the treatment averages of 851 IC and PC barrow carcasses. Lean cutting yield of IC barrows was 1.41 units greater ( P < 0.0001) than PC barrows (70.97 vs. 69.56%). Similarly, CCY of IC barrows was 1.29 units greater ( P < 0.001) compared with PC barrows (87.27 vs. 85.98%). As HCW of IC barrows increased, both CCY and LCY declined ( P < 0.01), with light IC barrow carcasses having a 1.43 unit advantage in CCY compared with heavy IC barrow carcasses ( P < 0.01). Natural fall bellies of PC barrows comprised a greater ( P < 0.05) percentage of side weight than those from IC barrows (15.81 vs. 15.50%). A reduction in belly primal value was confirmed by a 3.43 unit reduction in the commercial bacon slicing yields of IC barrows. However, belly yield and slicing yield differences were minimized when IC barrows were marketed at a heavier weight. Using carcass cutout estimates determined in the summary as the foundation for value calculations, lean cuts of IC barrow carcasses were worth $2.66 to $3.80 more than PC barrow carcasses. Therefore, after adjustment for the reduction in belly primal value, the primal value of an IC barrow carcass was $2.08 to $3.13 greater than a PC barrow carcass.

The objective was to characterize the relationship between fresh loin quality with fresh belly or fresh and cured ham quality. Pigs raised in 8 barns representing 2 seasons [cold ( = 4,290) and hot ( = 3,394)] and 2 production focuses [lean ( = 3,627) and quality ( = 4,057)] were used. Carcass characteristics and other meat quality data were collected on 7,684 carcasses. All of the carcasses were evaluated for HCW, LM depth, tenth rib fat depth, leg (ham primal) weight, instrumental color on the gluteus medius and gluteus profundus of the ham face, and subjective loin quality. Instrumental loin color and ultimate pH (≥ 22 h postmortem) were collected on the ventral side of loins along with dimensions and firmness scores of fresh bellies from 50% of the carcasses. Ten percent of the boneless loins and fresh hams were evaluated for slice shear force (SSF) or cured ham characteristics. Correlation coefficients between traits were computed using the CORR procedure of SAS and considered significantly different from 0 at ≤ 0.05. Temperature decline, beginning at 31 min postmortem and concluding at 22 h postmortem, for the longissimus dorsi and semimembranosus muscles were evaluated on 10% of the carcasses. Ultimate loin pH was correlated with dimensional belly characteristics ( ≥ |0.07|; < 0.0001) fresh ham instrumental color ( ≥ |0.03|; ≤ 0.05), and semimembranosus ultimate pH ( = 0.33; < 0.0001). Further, ultimate loin pH was correlated ( ≤ 0.01) with pump retention ( = 0.087) and cooked yield ( = 0.156) of cured hams. Instrumental L*on the ventral surface of the loin was related to L* on both muscles of the ham face ( ≤ 0.0001). Even though significant relationships between the loin, belly, and ham were detected, the variability in belly and ham quality explained by variability in loin quality was poor (≤ 22.09%). Compositional differences between the loin and belly may have contributed to those poor relationships. Additionally, differences in temperature declines during chilling between the loin and ham likely contributed to the weak nature of relationships. Equilibration of longissimus dorsi temperature to ambient cooler temperature occurred at 14 h postmortem ( = 0.0005), yet the semimembranosus had not equilibrated with ambient (equilibration bay) temperature ( < 0.0001) at 22 h postmortem. Using loin quality to draw conclusions about fresh belly and fresh and cured ham quality may be misleading.

The objective was: 1) to characterize the effect of marketing group on fresh and cured ham quality, and 2) to determine which fresh ham traits correlated to cured ham quality traits. Pigs raised in 8 barns representing 2 seasons (hot and cold) and 2 production focuses (lean and quality) were used. Three groups were marketed from each barn. A total of 7,684 carcasses were used for data collection at the abattoir. Every tenth carcass was noted as a select carcass for in-depth ham quality analyses. Leg primal weight and instrumental color were measured on 100% of the population. On the select 10% of the population, hams were fabricated into sub-primal pieces, and 3-piece hams were manufactured to evaluate cured ham quality and processing yield. Data were analyzed as a split-plot design in the MIXED procedure of SAS with production focus as the whole-plot factor, and marketing group as the split-plot factor. Pearson correlation coefficients between fresh and cured ham traits were computed. There were no differences ( ≥ 0.15) in instrumental color or ultimate pH ( ≥ 0.14) among fresh ham muscles from any marketing group. The only exception was the semimembranosus of marketing group 2 was lighter than marketing group 1 ( = 0.03) and the dark portion of the semitendinosus muscle from group 1 was lighter than from group 3 ( = 0.01). There were no differences ( ≥ 0.33) in ultimate pH of fresh ham muscles between production focuses, but several muscles from quality focus pigs were lighter in color than ham muscles from lean focus pigs. The lack of differences in fresh ham quality lead to few differences in cured ham quality. Cured hams from the quality focus pigs had greater lipid content ( < 0.01) than hams from lean focus pigs. Cured lightness values of hams from marketing group 1 and 2 were 1.52 units lighter than hams from marketing group 3 ( 0.01). Overall, marketing group did not impact ham quality. Fresh ham quality was not strongly related to cured ham quality. Some correlations were present between fresh and cured ham traits, but those relationships were likely not strong enough to be used as a sorting tool for fresh hams to generate high quality cured hams.

The objective of the current study was to evaluate the effects of aging on myoglobin chemistry of dark-cutting beef. Ten USDA Choice (mean pH = 5.6; normal pH beef) and 10 no-roll dark cutter (mean pH = 6.4) strip loins were obtained from a commercial packing plant within 3 d of harvest. Loins were cut into 4 sections, vacuum packaged, randomly assigned to 0-, 21-, 42-, and 62-d aging at 2°C in the dark. Following aging, loin sections were cut into 2.5-cm-thick steaks and were used to determine bloom development, oxygen consumption (OC), metmyoglobin reducing activity (MRA), and lipid oxidation. Surface color readings were measured using a HunterLab Miniscan XE Plus spectrophotometer. A significant muscle type × aging time interaction resulted for OC ( < 0.001). Normal pH steaks declined more ( < 0.001) in OC during aging than dark-cutting beef. On d 0, dark-cutting beef had a greater OC ( < 0.001) than normal pH beef. There was a significant muscle type × oxygenation time × aging period interaction for L* values, deoxymyoglobin (DeoxyMb), and oxymyoglobin (OxyMb). When dark-cutting sections were aged for 62 d, both 0 and 60 min bloom development L* values were greater ( < 0.0001) than 0 min dark-cutting sections aged for 21 or 42 d. At all aging periods, normal pH beef had greater OxyMb content and lower DeoxyMb ( < 0.0001) during bloom development than dark-cutting beef. An aging period × muscle type interaction was significant for % overall reflectance ( = 0.0017) and absorbance ( = 0.0038). Dark cutting and normal pH beef loin sections aged for 62 d had greater reflectance ( < 0.0001) than 21 d. On d 0, dark-cutting beef had greater ( < 0.0001) MRA than normal pH beef. There were no significant ( = 0.14) differences in MRA between 42 and 62 d between dark-cutting and normal pH beef. Dark cutting steaks had lower thiobarbituric acid reactive substances values ( < 0.0001) than normal pH steaks. The results indicate that characterizing the myoglobin chemistry during aging will help to design strategies to improve appearance of high pH beef.

The objectives of this study were to determine the effect of 1) immunological castration (Improvest, a gonadotropin releasing factor analog-diphtheria toxoid conjugate) management strategy (age at slaughter and time of slaughter after second dose) and 2) sex on lipid oxidation and sensory characteristics of bacon stored under simulated food service conditions. For Objective 1, immunological castration management strategies included 24-wk-old immunologically castrated (IC) barrows 4, 6, 8, or 10 wk after the second Improvest dose (ASD); 26-wk-old IC barrows 6 wk ASD; and 28-wk-old IC barrows 8 wk ASD ( = 63). Objective 2 ( = 97) included IC barrows, physically castrated (PC) barrows, and gilts slaughtered at 24, 26, and 28 wks of age. Bellies from 2 slaughter dates were manufactured into bacon under commercial conditions. Bacon slices were laid out on parchment paper, packaged in oxygen-permeable poly-vinyl-lined boxes, and frozen (-33°C) for 1, 4, 8, or 12 wk to simulate food service conditions. At the end of each storage period, bacon was evaluated for lipid oxidation, moisture and lipid content, and sensory characteristics. Data from both objectives were analyzed using the MIXED procedure in SAS with belly as the experimental unit. For both objectives, as storage time increased, lipid oxidation of bacon increased ( < 0.01), regardless of management strategy or sex. Also, there was no sex or management strategy × week of frozen storage interaction for any traits evaluated ( ≥ 0.25). For Objective 1, lipid content of bacon from IC barrows increased as time of slaughter ASD increased ( < 0.05), regardless of age at slaughter. Additionally, there were no differences in sensory attributes of bacon across management strategies. For the evaluation of sex effects in Objective 2, lipid oxidation was greater ( < 0.05) in IC barrows compared with PC barrows but was not different than gilts ( > 0.05). After 12 wk of frozen storage, lipid oxidation values for IC barrows, PC barrows, and gilts were still below 0.5 mg malondialdehyde/kg of meat, the threshold at which trained panelists may deem a food to be rancid. In conclusion, bacon shelf life characteristics were not altered by the immunological castration management strategy and bacon from IC barrows was similar to bacon from gilts. Therefore, bacon from IC barrows would result in shelf life and sensory quality similar to PC barrows and gilts.