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, post-slaughter hide-on animals (n = 6,674), carcasses (n = 5,746), and offal items (heads and tongues: n = 7,282; lungs and hearts: n = 6,708; viscera, kidneys, and livers: n = 6,358) were surveyed at 20 commercial beef processing facilities across the United States. There were 37.8% of cattle with no visible mud contamination. Native (unbranded) hides were observed in 88.3% of cattle. Carcass bruising was observed on 66.7% of cow carcasses and 46.4% of bull carcasses, similar to percentages observed in the 2007 and 2016 audits. Nearly all cattle were free of knots (98.2%) or injection-site lesions (97.1%). Harvest-floor assessments found that 45.0% of livers, 22.2% of viscera, 19.3% of kidneys, 46.6% of lungs, 19.9% of hearts, 11.2% of heads, and 6.4% of tongues were condemned. The leading cause of condemnation for these offal items was contamination, aside from livers with the majority resulting in condemnation from the presence of an abscess. Of the cows surveyed, 25.4% carried a fetus, an 8% increase compared to those observed in 2016, and a 14.8% increase compared to cows surveyed in 2007. Findings from the NBQA-2022 identified areas of improvement and areas that required continued research and producer education to improve market cow and bull welfare, by-product quality, and offal value. This aspect of the National Beef Quality Audit-2022 focused on hide characteristics, defects visible on the carcass surface, and offal condemnations related to animal welfare and the value of beef and dairy market cows and bulls. This comprehensive survey provides detailed findings related to the types of defects observed on hides, the quantity and severity of bruises, visible injection-site presence, offal condemnations, and pregnancy status of cows at harvest. This aspect of the National Beef Quality Audit-2022 focused on hide characteristics, defects visible on the carcass surface, and offal condemnations related to animal welfare and the value of beef and dairy market cows and bulls. Fewer than half (37.8%) of the cattle were free of visible mud contamination on the hide at the time of harvest. Most hides observed (88.3%) were native or unbranded, which is an increase from the rate observed in the previous audit. Hide damage due to reasons other than branding was observed in 12.3% of all cattle surveyed. Only 3.3% of all cattle surveyed had heads or limbs drag on the harvest floor or equipment due to carcass size. The percent of carcasses with bruising was similar to those reported in the 2007 and 2016 audits with cows at 66.7% and bulls at 46.4%, respectively. Nearly all cattle were free of knots (98.2%) or injection-site lesions (97.1%). Harvest-floor condemnation rates were 11.2% of heads, 6.4% of tongues, 46.6% of lungs, 19.9% of hearts, 22.2% of viscera, 19.3% of kidneys, and 45.0% of livers with heads, tongues, and kidneys being condemned at a greater rate than observed in 2016. The leading cause of condemnation for these offal items was contamination, aside from livers with the majority resulting in condemnation from the presence of an abscess. Of the cows surveyed, 25.4% carried a fetus at the time of harvest, an 8% increase compared to those observed in 2016, and a 14.8% increase from those surveyed in 2007. Improvements were observed in the instances and location of branding as well as decreased instances of knots or injection-site lesions, which can be attributed to improvements in management practices and producer education. Further improvements can be made to decrease the amount of mud present on the hide at the time of harvest, decrease instances of carcass bruising, and improve animal health to minimize offal condemnations. These improvements can benefit both animal welfare as well as carcass and offal value.

Our objective was to compare beta-agonist feeding strategies and evaluate Experior (EXP) with added days on feed (DOF) for live growth performance and carcass outcomes. Steers (n = 2,517; initial BW = 336 +/- 23 kg) were allocated to 36 pens in a randomized, complete-block design and assigned to 1 of 6 treatments. Treatments were negative control (no beta-ligand; CON), Optaflexx (ractopamine hydrochloride, 300 mghead-1day-1 for 35 d; OPT), and Experior (lubabegron fumarate, 36 mghead-1day-1 for 56 d + 4 d removal; 0EXP) with all three treatments fed for 198 d. Remaining treatments were fed EXP for same duration as 0EXP, but total DOF were adjusted by -14 d (-14EXP), +14 d (+14EXP) and +28 d (+28EXP). Statistical analyses were conducted using mixed models; treatment was the fixed effect, block was a random effect, means were separated with the Tukey-Kramer adjustment, and contrasts were calculated to test linear or quadratic effects of EXP across DOF. No treatment differences (P >= 0.72) were observed for daily dry matter intake. Calculated cumulative ammonia (NH3) gas emissions (CCAGE) expressed either as total NH3 emitted (g) or NH3 emitted per kg of BW or HCW was reduced (P < 0.01) by 5.6-8.5%, 5.1-10.7%, and 6.3-13.6%, respectively for 0EXP, +14EXP and +28EXP compared to CON. Carcass ADG of 0EXP steers was 6.8% greater (P < 0.01) than CON, which had similar (P >= 0.10) ADG to OPT, +14EXP, and +28EXP steers. Carcass G:F of 0EXP steers was improved 5.0% compared to CON (P = 0.01) and was not different (P >= 0.10) from OPT, -14EXP or +14EXP steers. Hot carcass weight of 0EXP, +14EXP, or +28EXP steers was 14-37 kg heavier (P < 0.01) than CON, which did not differ (P = 0.81) from OPT. Steers fed EXP had 1.15-2.5% point increase (P < 0.01) in dressed yields. Longissimus muscle area was 4.03-6.23 cm2 larger (P < 0.01) in steers fed EXP compared to CON, which tended to differ (P = 0.08) from OPT. Marbling score was 31-39 points lower (P <= 0.02) for -14EXP compared to CON and OPT, whereas 0EXP tended (P = 0.09) to differ from CON and +14EXP and +28EXP were similar (P >= 0.28) to CON and OPT. Slice shear force values were 20.1% greater (P < 0.02) for +14EXP compared to CON, whereas 0EXP tended (P = 0.09) to be greater and +28EXP, -14EXP and OPT were similar (P >= 0.28) to CON.This study illustrates EXP decreased CCAGE and increased HCW with minimal quality changes when fed the last 56 d on feed.

Objective: We investigated incremental growth of carcass and non-carcass components and tissue partitioning of implanted or non-implanted steers. Materials and Methods: Steers (n = 80; 271 +/- 45 kg) were paired and randomized to harvest date (d 0, 42, 84, 126, 168, 210, 252, 294, 336, or 378), and individuals within pairs were randomized to CON (negative control) or REV (Revalor-XS, Merck Animal Health, on d 0 and 190) treatments. Non-carcass components were removed, cleaned, and weighed. Growth coefficients were calculated using the allometric equation Y = bX a . Results and Discussion: Empty body weight (EBW), and hot carcass weight (HCW) were 6% greater ( P < 0.01) in REV steers versus CON. No treatment effects ( P >= 0.12) occurred for fill or dressed carcass yield (DY); however, EBW, HCW, and DY increased ( P <= 0.01) and percentage fill decreased as an effect of days on feed (DOF). Absolute fill weight did not change across DOF ( P = 0.82). Implanted steers had greater ( P <= 0.05) absolute mass of blood, head, hide, oxtail, liver, spleen, bladder, heart, reticulum, omasum, stomach, small intestine, intestines, gastrointestinal tract (GIT), total splanchnic tissue, and total offal. Implanted steers also had smaller ( P <= 0.05) absolute mass of thymus glands and kidney-pelvicheart fat (KPH) than non-implanted steers. Non-carcass components with lowest growth coefficients included small intestine (0.02), large intestine (0.12), and brain and spinal cord (0.13). However, KPH (2.01) accumulated at more than 2 times the rate of the empty body, whereas cod fat (1.42) and GIT fat (1.61) grew notably faster than the empty body. Implication and Applications: Results suggest that Revalor-XS increased body and carcass weights and altered many non-carcass components and their growth coefficients, ultimately playing key biological, nutritional, and financial roles across sectors of the beef industry.

Objective: We investigated the independent and interactive effects of dietary starch concentration and feeding management regimen on growth performance, carcass characteristics, and prevalence of liver abscesses in finishing beef cattle. Materials and Methods: Beef steers (n = 720) were assigned to 48 pens in a randomized complete block design, with treatments arranged in a 2 x 2 factorial (12 pens per treatment). Factors were finishing diets with either low (49.1%; CON) or high (64.4%; HOT) starch concentrations and feeding management regimens designed for consistent feed delivery (REG) or randomized variations (ERR) in both feed quantity (85% followed by 115% of the previous 4-d average randomly once per week) and delivery time (randomly delayed for 1, 2, 3, or 4 h twice per week). Results and Discussion: No interactions between diet and feeding management regimen were detected for growth performance, carcass outcomes, or liver abscess prevalence. Steers fed HOT had greater liver abscess frequency (55.1% vs. 33.4%) and a greater proportion of liver scars (46.7% vs. 34.0%) compared with CON. Steers consuming HOT also had less final BW, ADG, DMI, hot carcass weight, marbling score, and calculated YG versus CON. Feeding management regimen did not affect liver abscess frequency, growth performance, or carcass merit. Implications and Applications: Feeding a highstarch diet increased liver abscess prevalence and decreased growth and affected carcass outcomes. In contrast, erratic feeding management did not affect liver or production outcomes.

Holstein steers (n = 40; initial BW = 84.9 +/- 7.1 kg) were used to study the genesis of liver abscesses (LA) using an acidotic diet challenge with or without intraruminal bacterial inoculation. Steers were housed in individual pens inside a barn and randomly assigned to one of three treatments: (1) low-starch control diet comprised primarily of dry-rolled corn and wet corn gluten feed (CON); (2) high-starch acidotic diet with steam-flaked corn (AD); or (3) acidotic diet plus intraruminal inoculation with Fusobacterium necrophorum subsp. necrophorum (9.8 x 10(8) colony forming units [CFU]/mL), Trueperella pyogenes (3.91 x 10(9) CFU/mL), and Salmonella enterica serovar Lubbock (3.07 x 10(8) CFU/mL), previously isolated from LA (ADB). Steers in AD and ADB were fed the acidotic diet for 3 d followed by 2 d of the CON diet, and this cycle was repeated four times. On day 23, ADB steers were intraruminally inoculated with the bacteria. At necropsy, gross pathology of livers, lungs, rumens, and colons was noted. Continuous data were analyzed via mixed models as repeated measures over time with individual steer as the experimental unit. Mixed models were also used to determine the difference in prevalence of necropsy scores among treatments. Ruminal pH decreased in AD and ADB steers during each acidotic diet cycle (P <= 0.05). LA prevalence was 42.9% (6 of 14) in ADB vs. 0% in AD or CON treatments (P < 0.01). Ruminal damage was 51.1% greater in ADB than in AD (P <= 0.04). Culture of LA determined that 100% of the abscesses contained F. necrophorum subsp. necrophorum, 0% contained T. pyogenes, 50% contained Salmonella, and 50% contained a combination of F. necrophorum subsp. necrophorum and Salmonella. The F. necrophorum subsp. necrophorum was clonally identical to the strain used for the bacterial inoculation based on phylogenetic analysis of the whole genome. This experimental model successfully induced rumenitis and LA in Holstein steers and confirms the central dogma of LA pathogenesis that acidosis and rumenitis lead to the entry of F. necrophorum into the liver to cause abscesses. Our findings suggest that an acidotic diet, in conjunction with intraruminal bacterial inoculation, is a viable model to induce LA. Further research is needed to determine the repeatability of this model, and a major application of the model will be in evaluations of novel interventions to prevent LA.

Abstract The objective of this study was to determine if ultrasound estimates of carcass quality traits could predict the final quality factors that influence purchases of consumers. Beefmaster steers (n = 86) representing two different sires were ultrasounded 48 d and 73 d before harvest using an Aloka 500 ultrasound unit, equipped with a 17.2cm probe to collect 12th rib fat thickness (BFU), 12th rib longissimus muscle area (LMAU), intramuscular fat (%FATU) and rump fat (RFU). International Livestock Image Analysis (I.L.I.A) software (Harrison, Arkansas) was used for processing images to determine BFU, LMAU, %FATU and RFU using chute side captured ultrasound images on all steers. An Ultrasound Guidelines Council (UGC) field and lab certified technician captured all ultrasound images. Carcass data collection included 12th rib fat thickness (BFC), 12th rib longissimus muscle area (LMAC) and marbling score (MS). Additionally, Warner Bratzler shear force (WBSF) and ether extraction (EE) estimates were determined on 12 to 13th longissimus muscle samples. All carcass data was collected by the Beef Carcass Research Center (BCRC) at West Texas A&M University. Data were analyzed using SAS version 9.4. Simple descriptive statistics were 1.03 ± 0.26 cm, 88.8 ± 8.61 cm2, 5.02 ± 0.93, 1.27 ± 0.36 for BFU, LMAU, %FATU, and RFU, respectively. Simple descriptive statistics were 1.72 ± 0.41 cm, 90.06 ± 7.24 cm2, 5.06.7 ± 0.69, 6.08 ± 1.92, and 3.34 ± 0.79 kg for BFC, LMAC and MS, EE and WBSF, respectively. Pearson correlation coefficients were 0.71 (P < 0.001) between BFU and BFC, 0.42 (P < 0.0001) between LMAU and LMAC, and 0.35 (P < 0.001) between %FATU and MS. Pearson correlation coefficients were 0.42 (P < 0.001) between EE and %FATU and 0.59 (P < 0.0001) between EE and MS. These results suggest that ultrasound measures of final body composition should be taken closer to the final harvest date to better estimate endpoints of fat thickness, longissimus muscle area and intramuscular fat in harvest ready beef cattle.

We examined the effect of maceration frequency on surface area, purge loss, and palatability of eye of round and bottom round steaks. Beef eye of round (n = 12) was cut into 8 steaks each and randomly assigned to 0, 1, 2, or 3 macerations and uncooked or cooked slice shear force (SSF) tenderness determinations. Bottom round muscles (n = 12) were cut into 12 steaks and randomly assigned to 0, 1, 2, or 3 macerations and uncooked or cooked SSF or trained sensory evaluations. Steaks were trimmed to a common size (50 cm2 for eye of round and 80 cm2 for bottom round) prior to maceration with a commercial steak tenderizer. Data were analyzed via mixed ANOVA models using a randomized complete block design. Surface area increased (P < 0.001) by 15.4%, 38.6%, and 62.4% for eye of round steaks and 22.0%, 51.3%, and 70.3% for bottom round steaks after 1, 2, or 3 macerations, respectively. Purge losses did not differ (P ≥ 0.247) for either muscle due to maceration frequency. Uncooked SSF values for eye of round steaks were decreased (P < 0.001) by 6.6%, 19.5%, and 40.0% after 1, 2, and 3 macerations; however, cooked SSF values did not differ (P = 0.077). For bottom round steaks, uncooked SSF values were decreased (P < 0.001) by 32.0%, 45.5%, and 67.2% after 1, 2, and 3 macerations; cooked SSF values for steaks macerated 3 times were 26.6% lower (P = 0.022) than steaks macerated 0, 1, or 2 times. Cooking losses were greater (P < 0.001) for macerated eye of round (5.4% to 7.2%) and bottom round steaks (7.6% to 10.8%). Maceration decreased (P < 0.001) sensory juiciness and connective tissue ratings and increased (P < 0.001) sensory tenderness ratings. Maceration increased surface area and improved tenderness.

Objective: The objective was to evaluate the effect of days on feed (DOF) on performance and carcass characteristics of crossbred beef x dairy heifers. Materials and Methods: Beef x dairy heifers (n = 3,765; initial BW = 508 +/- 8.55 kg) were blocked by arrival date and lot (n = 6 blocks at feedyard 1 and n = 7 blocks at feedyard 2) and randomly assigned to 1 of 4 DOF treatments of 323, 344, 362, or 385 when administered a Revalor-200 (200 mg of trenbolone acetate [TBA] and 20 mg Results and Discussion: Dry matter intake was not from 593 to 655 kg. As DOF increased, ADG and gain: calculated YG, and marbling score increased linearly as DOF increased. Across the 63-d serial slaughter period, hot carcass weight increased 0.67 kg/d. Dressing percentage and backfat thickness increased in a quadratic manner across DOF. Further, QG and YG distribution increased linearly as DOF increased. Liver abscess prevalence or severity did not increase with DOF. Implications and Applications: Results of this study dairy crossbred heifers.

Abstract Liver abscesses present significant challenges for the beef industry, yet understanding of the interplay between diet composition, eating behavior, and ruminal acidosis in finishing cattle and their effects on liver abscess prevalence and growth performance is lacking. Therefore, this study investigated the independent and interactive effects of dietary starch concentration and feed delivery regimen on growth performance, rumen buffering characteristics, carcass outcomes, and prevalence of liver abscesses in finishing beef steers. On d 0, beef steers [n = 720; body weight (BW) = 407 ± 4.53 kg) were sorted into 12 blocks according to BW and assigned to 1 of 4 treatments arranged as a 2 × 2 factorial (12 pens/interaction treatment; 24 pens/main effect) in a randomized complete block design. Treatments were finishing diets with low (49.1%; CON) or high (64.4%; HOT) starch concentration fed to steers receiving consistent feed delivery (REG) or randomized variations (ERR) in feed quantity (85% followed by 115% of the previous 4-d average once per week) and delivery time (delayed for 1, 2, 3, or 4 h twice per week). The 3 steers closest to the median BW in each pen were administered a 3-axis accelerometer ear-tag to quantify time spent ruminating and an indwelling rumen bolus to measure ruminal pH for the first 150 d of the study. Fecal score (1 = hard and dry consistency to 5 = water like consistency) and fecal pH were recorded on d 0, 56, 112, and before harvest. Daily dry matter intake (DMI) variability was greatest (P < 0.01; diet × feed delivery interaction) for CON + ERR, intermediate for HOT + ERR, and least for HOT + REG and CON + REG. No additional interactions (P ≥ 0.14) between diet and feed delivery regimen were observed. Feeding HOT increased total liver abscesses (P < 0.01) by 21.7 percentage points and liver scars (P < 0.01) by 12.7 percentage points compared with CON. Additionally, steers consuming HOT had less (P ≤ 0.05) final BW, average daily gain, DMI, gain-to-feed ratio, hot carcass weight, marbling score, and yield grade than CON. Steers fed HOT also had fewer daily rumination minutes (P < 0.01; diet × day interaction), lower fecal pH (P < 0.01; diet × day interaction) lower ruminal pH (P = 0.04), and less desirable fecal scores (P = 0.02) vs. CON. Feed delivery regimen did not affect (P ≥ 0.21) growth performance, rumen buffering characteristics, carcass traits, or liver abscess prevalence. Increasing the concentration of readily fermentable starch fed to finishing steers reduced growth and carcass performance, ruminal pH, and fecal pH, while increasing the proportion of liver abscesses. In contrast, inducing erratic DMI did not affect growth performance or carcass outcomes.

An overview of the fundamental principles of vacuum packaging is provided in this article, with emphasis on myoglobin chemistry, packaging film traits, and application mechanics. In-depth information provides insight into vacuum/pressure level and measurement, muscle pigments and discoloration, film permeability, shelf life and microbiology, bag sizing, package sealing, and wholesale versus retail acceptance.

Abstract Liver abscesses pose a significant economic burden on the beef industry, resulting in substantial profit losses. A contributor to these losses is the decreased productivity and feed efficiency observed in affected cattle. Reduced feed efficiency could be attributed to the impairment of metabolic activity due to liver tissue damage caused by the abscesses. While tissue within the abscess itself is dysfunctional, little is known about the functional state of the surrounding liver tissue. Considering this, the present research aimed to evaluate liver tissue gene expression profiles at varying distances from liver abscesses. Tissue samples (n = 21) were collected from three distinct regions: 1) <4 mm proximal from the abscess without including abscessed tissue (adjacent tissue), 2) 3 cm proximal from the abscess (nearby tissue), and 3) from livers with no abscesses (healthy controls). Gene expression comparisons utilizing DESeq were conducted between each tissue sample group. The number of differentially expressed genes (FDR ≤ 0.10) identified in each comparison is presented in Table 1. Tissue directly adjacent to the liver abscess was substantially different in gene expression when compared with both the healthy and tissue 3 cm proximal to an abscess. Fewer genes exhibited differential expression between healthy tissue and tissue taken 3 cm away. Gene enrichment analysis was conducted using the KOBAS-i software to identify biological pathways associated with the differentially expressed genes. Genes upregulated in liver tissue adjacent to the abscess were associated (FDR ≤ 0.10) with immune response pathways, including the “T cell receptor signaling pathway” and “Cytokine-Cytokine receptor interaction,” whereas downregulated genes were linked to metabolic pathways such as “Fatty Acid Metabolism” and multiple amino acid biosynthesis pathways. Gene expression differences between tissue 3 cm away and healthy tissue were minimal; however, enrichment analysis identified significant (FDR ≤ 0.10) metabolic pathways such as the “peroxisome proliferator-activated receptor signaling” which is involved in gluconeogenesis and lipid metabolism, suggesting some metabolic alterations up to 3 cm proximal from the abscess. Upregulation of immune response pathways and downregulation of metabolic pathways in the adjacent tissue suggest a shift in cellular priorities, diverting resources to combat the active infection rather than routine metabolic processes. This localized immune response and metabolic dysregulation observed in the liver tissue adjacent to the abscess, coupled with metabolic alterations up to 3 cm away, highlight the effects of liver abscesses on the overall metabolic capacity and functionality of the liver. Continued research should focus on investigating the effect of abscess severity on overall liver function.

Abstract Our objective was to evaluate hematological measurements that could be indicative of liver abscesses (LA) in weaned beef × dairy cross steers. Beef × dairy cross steers [n = 40; initial body weight (BW) = 120 ± 12 kg] were sourced from a local dairy calf ranch and transported 166 km to the USDA-ARS Livestock Issues Research Unit Liberty Farm near Lubbock, TX (d -16). Calves were initially housed outside in soil-surfaced pens for 16 d with ad libitum access to water and high-forage receiving diet before being moved into individual pens within an environmentally controlled barn (d 0). While housed in the barn, calves were cycled between a high-forage diet (2 d) and a high-concentrate finishing diet (3 d) for 3 cycles. Additionally, calves were administered Fusobacterium necrophorum subsp. necrophorum (4.25 x 106 CFU in 100 mL) and Salmonella enterica serotype Lubbock (1.29 x 106 CFU in 100 mL) intraruminally on d 0, 5, and 10. Following the last inoculation on d 10, calves were fed the high concentrate finishing diet for the remainder of the study. Whole blood samples for measurement of complete blood counts were collected via jugular venipuncture on d 0, 10, 21 and 30. On d 31, calves were harvested to determine LA prevalence. Fifty percent of calves developed at least one LA. Complete blood count analysis revealed day effects (P ≤ 0.03) for all variables, with the exception of basophil percentage (P = 0.06; Table 1). Prevalence of a liver abscess was associated with increased (P < 0.01) neutrophil count, neutrophil:lymphocyte ratio, and neutrophil percentage, concomitant with decreased (P ≤ 0.04) lymphocyte percentage, and monocyte percentage. Additionally, a tendency (P = 0.09) was observed for decreased red blood cells in calves with a LA compared with those without. These data suggest that changes in neutrophil and lymphocyte concentrations within the blood may be indicative of LA prevalence in beef × dairy steer calves and hold potential as predictive markers for LA.

Our objective was to evaluate the combined effect of blast freezing vacuum packaged USDA Low Choice Longissimus lumborum beef steaks followed by consumer freezing of retail overwrapped steaks upon objective and subjective measures of beef palatability. The experimental design utilized a randomized complete block with a 3 × 3 treatment structure of targeted freezing treatments initially in vacuum and secondly in overwrap packaging (unfrozen = NOT; blast frozen at −34.4°C = BF; consumer-frozen at −17.8°C = CF) to accomplish 9 treatment combinations. Descriptive sensory attributes were evaluated by trained panelists on a 100-point line scale. Slice shear force and expressible moisture were assessed. Data were analyzed via PROC GLIMMIX using a randomized complete block design with a 3 × 3 treatment structure. Of descriptive panel attributes, overall juiciness was the only interaction observed (P = 0.006). Though similar to steaks initially CF in the vacuum package and followed by a second freeze (CF/BF or CF/CF) in the overwrap package, steaks singly frozen to simulate a CF (CF/NOT and NOT/CF) resulted in the overall driest ratings by panelists (P = 0.006). Only bloody/serumy differed (P = 0.002) within the initial freeze, where steaks not frozen (NOT) in the vacuum package were rated higher than those that were frozen (BF or CF). During the second freeze in the overwrap package after retail display, steaks BF rated higher for oxidized (P = 0.051) off-flavor than steaks CF and higher than both CF and NOT steaks for refrigerator-stale (P = 0.006) off-flavor; all other attributes did not differ (P ≥ 0.155). Although some freezing combinations that included CF were generally lower for overall juiciness, BF vacuum packaged steaks had no effect on palatability when compared to NOT steaks. The beef industry and consumers should feel confident using freezing as a means to extend shelf-life of beef steaks.

Limited research has compared no beta-agonist, ractopamine and lubabegron in feedlot cattle. We evaluated carcass quality and yield variables using a camera grading instrument and also examined objective tenderness outcomes. Treatments were negative control (no beta-ligand; CON), Optaflexx (ractopamine hydrochloride, 300 mg·steer-1·d-1 for 35 d; OPT), and Experior (lubabegron fumarate, 36 mg·steer-1·d-1 for 56 d + 4 d removal; 0EXP) fed for 198 d. Additional EXP treatments investigated total days on feed (DOF) of 184 d (-14EXP), 212 d (+14EXP) and 226 d (+28EXP). Carcasses (n = 2,517) were instrument graded 24 h post-mortem. Longissimus tenderness and lipid content were evaluated in a subset (n = 361) of carcasses via slice shear force and ether extract. Statistical analyses were conducted using mixed models; pen was the experimental unit, treatment was the fixed effect, block was a random effect, and means were separated with the Tukey-Kramer adjustment. Longissimus muscle area (LMA) was 4.0 to 6.2 cm2 larger (P < 0.01) for steers fed EXP compared with CON, which did not differ from OPT. Weight corrected LMA (LMA:HCW) was 1.3 cm2/100 kg larger (P < 0.01) for -14EXP compared with CON. Marbling score was 31 to 39 points lower (P < 0.01) for -14EXP compared with CON and OPT, whereas 0EXP, +14EXP and +28EXP were similar to CON and OPT. Total number of fat pieces within the longissimus did not differ (P = 0.11) across treatments, however number of fat pieces in the lateral one-half of the longissimus decreased (P ≤ 0.03) for -14EXP and +28EXP, whereas +14EXP tended (P = 0.09) to decrease compared with CON. Total meat area was 3.7 percentage points greater (P < 0.01) for -14EXP compared with CON; +14EXP and +28EXP tended (P = 0.07) to be greater than CON. Total fat area was 1.6 to 1.8 percentage points less (P ≤ 0.02) for 0EXP, +14EXP, and +28EXP when compared with CON. Compared with CON, dorsal-ventral longissimus distance increased (P < 0.01) by 3.3 to 5.4% for -14EXP, 0EXP, +14EXP and +28EXP. Medial-lateral longissimus distance increased 1.9 to 2.5 % (P < 0.01) for +14EXP and +28EXP compared with CON, whereas -14EXP tended (P = 0.08) to increase. Percentage intramuscular fat (IMF) was similar (P ≥ 0.44) for +14EXP, +28EXP, and OPT compared with CON, whereas 0EXP tended (P = 0.09) to be less. Marbling score and IMF were moderately correlated (r = 0.66). Slice shear force values were 20.1% greater (P < 0.02) for +14EXP compared with CON, whereas 0EXP tended (P = 0.09) to be greater and +28EXP, -14EXP and OPT were similar (P ≥ 0.28) to CON. These findings illustrate the effect of EXP on carcass traits and tenderness in feedlot cattle.

Abstract Liver abscesses (LA) continue to be an economic challenge for the beef industry. Chronic ruminal acidosis and ruminitis contribute to LA development. Fusobacterium necrophorum subsp. necrophorum, a ruminal bacterium, is the primary causative agent. Damaged ruminal, and possibly other gut regions, become susceptible to invasion and colonization by subsp. necrophorum, which reaches the liver via portal blood to cause abscesses. We hypothesize that the LA occurrence is related to the presence and concentrations of subsp. necrophorum in gut contents and epithelial tissues. Our primary objective was to detect, isolate and quantify subsp. necrophorum in gut contents and tissues in steers with experimentally induced LA. An experimental model, which included ruminal acidosis followed by intraruminal inoculation of subsp. necrophorum alone or with Salmonella enterica serotype Lubbock, was used to assess the relationship. Steers (n = 61) from three independent studies with three treatment groups were used. Treatments included: 1) forage-based diet with intraruminal inoculation of subsp. necrophorum; 2) ruminal acidosis with intraruminal inoculation of subsp. necrophorum; and 3) ruminal acidosis with intraruminal inoculation of subsp. necrophorum and S. Lubbock. Steers were euthanized 3 wk after bacterial inoculation and liver, gut contents, and tissue samples (ruminal, ileal and colonic) from steers with LA (n = 27) and with healthy livers (n = 34) were collected and subjected to culture method and quantitative PCR to isolate, detect, and quantify subsp. necrophorum. Data were analyzed by PROC GLIMMIX of SAS after summarizing frequency of isolation in various sample types within each study for steers with and without LA and converted to a binomial proportion. Concentrations were analyzed using steer as the experimental unit. The model included the fixed effect of liver status (abscessed or not) and study as the random effect. The frequency of isolation and mean concentration of subsp. necrophorum in purulent materials of LA were 100% and 3.5 x 107 Log10 CFU/g, respectively. The frequency of isolation of subsp. necrophorum from ruminal tissues of steers with LA was greater than steers with healthy livers (35.4 vs 14.5%; P = 0.04). Likewise, the concentration of subsp. necrophorum in ruminal tissues was greater in steers with LA than with healthy livers (4.2 vs 3.6 Log10 CFU/g; P < 0.001). None of the ileal and colonic tissues, except one ileal tissue in each group, yielded subsp. necrophorum. The concentrations of subsp. necrophorum in ruminal, ileal, and colonic contents did not differ (P = 0.9) between steers with LA or with healthy livers. Our data suggest that the occurrence of LA is positively related to prevalence and concentration of subsp. necrophorum in ruminal tissue, and the colonization likely serves as a source of continuous flow of bacterial emboli into the portal blood to initiate LA development.

Abstract Chronic passive congestive (CPC) livers are reported as one of the most common clinical signs of right-sided Bovine Congestive Heart Failure (BCHF). Frequency of CPC livers at harvest and the associated loss of offal and carcass value does not appear in the literature. Our objectives were to 1) quantify the frequency of CPC livers at harvest within the Texas Panhandle, and 2) evaluate the association with offal and carcass outcomes. Audits were performed over the duration of a production week (both harvest shifts) per each large commercial beef processing facility (4 total) in the Texas Panhandle. West Texas A&M University trained personnel identified CPC (large blue) livers at evisceration and documented heart score (HS; scale 1 = normal to 5 = extreme structural changes), liver weight, USDA-FSIS inspection fate (U.S. Inspected & Passed; U.S. Condemned) of the liver, remaining viscera, and carcass. Other visual observations (sex, predominant black hair coat color, carcass/visceral edema, liver abscesses) were noted. 1) Frequency data were documented among cattle-type populations: sex (steers, heifers, cows, bulls), and phenotype [native, dairy-cross, dairy, category-B (Mexico-origin)]. 2) Carcass and lot identification were collected for the purpose of tracking and obtaining carcass grading data. Of carcasses deemed wholesome-U.S. Inspected & Passed, USDA yield and quality metrics [hot carcass weight (HCW), 12th-rib fat thickness (FT), ribeye area (REA), marbling score (MS)] of those identified with CPC, as well as data for the balance of respective lots were collected. Carcass outcomes of those exhibiting a CPC liver were compared with the outcomes of remaining lot. Frequency data were analyzed via chi-square. Carcass data were analyzed using mixed models, where occurrence of CPC liver was the fixed effect; facility, cattle type, and sex were random effects. A total of 83,527 animals were audited, with a CPC liver frequency of 0.17% (n = 144). Frequencies among sex (steer = 0.16%; heifer = 0.17%; cow = 0.33%; P < 0.01) and phenotypes (native = 0.15%; category-B = 0.04%; dairy cross = 0.14%; P = 0.01) were documented. Heart scores ranged from 1 to 4, with HS 3 occurring most frequently [HS 1 (n = 2); HS 2 (n = 39); HS 3 (n = 62); HS 4 (n = 17)]. Weights of CPC livers ranged from 7.3 kg to 34.4 kg; the heaviest CPC livers were recorded in cows (mean = 17.2 kg; P < 0.01). Despite USDA-FSIS guidelines, 2.08% of CPC livers were U.S. Inspected & Passed, along with 16.90% of viscera and 84.03% of carcasses. Cow carcasses encountered the greatest U.S. Condemn-rates (38.24%) among the sex categories. Within the fed-beef population, natives were the only category resulting in U.S. Condemned carcasses (10.64%). All carcass outcomes were decreased (P ≤ 0.01) by CPC livers.

Abstract We evaluated the association of diet type, ruminal acidosis bout frequency, and intraruminal bacterial inoculum concentration on liver abscess (LA) development in steers. Beef × dairy steers [n = 40, initial body weight (BW) = 107 ± 11 kg] were assigned randomly to 1 of 5 treatments that included either a high-dose (HD; 1 × 109 and 1 × 109 CFU/mL) or a low-dose (LD; 1 × 106 and 1 × 106 CFU/mL) of Fusobacterium necrophorum subsp. necrophorum and Salmonella enterica serovar Lubbock, respectively. Treatments included: NCON = high-forage diet with no intraruminal inoculation; CON+HD = high-forage diet with a single, HD inoculation; 2AD+HD = 2 acidotic diet cycles with a single, HD inoculation; 4AD+3LD = 4 acidotic diet cycles with a series of 3 LD inoculations; and 4AD+HD = 4 acidotic diet cycles with a single, HD inoculation. Individual animal was the experimental unit. Continuous data were analyzed using mixed models, and categorical data were analyzed as binomial proportions with treatment, time, and their interactions as the fixed effects. Hematology was evaluated before harvest on d 21 to evaluate indications of systemic disease. Although no difference was observed in rumenitis among treatments (P = 0.79), steers with LA presented with 8 percentage points greater rumenitis than steers without LA. Steers consuming the high-forage diet also presented with rumenitis. Prevalence of LA was 0, 37.5, 37.5, 50, and 12.5% for NCON, CON+HD, 2AD+HD, 4AD+3LD, and 4AD+HD, respectively (P = 0.68). A key observation of this study was that steers fed a high-forage diet presented with LA when dosed with of F. necrophorum and S. enterica, even in the absence of the acidotic diet.

The contribution of kidney, pelvic, and heart (KPH) fat to predicting carcass yield in the official USDA Yield Grade equation has been questioned in the modern U.S. slaughter cattle population and has not been extensively studied. Many U.S. beef processors remove KPH fat at harvest to facilitate faster chilling and easier fabrication. The objective of this study was to understand the modern-day relationship of KPH fat to subprimal yield (SY). Fabrication data from carcasses (N= 816) evaluated across multiple studies in the last 15 y were summarized. SY, subprimal cutout value (SCO), and KPH percentage were adjusted to account for study effects. Values for SY, SCO, and KPH percentage were computed on a conventional (hot side weight [HSW] including KPH) and alternate (HSW without KPH) basis, and variance among these measures was tested. Relationships among HSW and carcass components, carcass components themselves, and conventional and alternate calculations of SY and KPH percentages were evaluated using linear and quadratic models. Variance in alternate KPH percentage was greater (P = 0.01) than conventional KPH, suggesting that variance in KPH was independent from variance associated with HSW. Among carcass components, KPH weight was least related (R2 linear = 0.167, and R2 quadratic = 0.201) to HSW. Subprimal (SUB) and fat, bone, and trimmings (FBT) weight were each more directly related (R2 = 0.899 to 0.953) to HSW. Weight of KPH was poorly related to weight of SUB (R2 = 0.074) and FBT (R2 = 0.127), although quadratic relationships of these same metrics were slightly stronger. Therefore, to increase accuracy, future models predicting carcass yield should incorporate an accurate measure of KPH or exclude KPH altogether from the denominator of the yield calculation.

Abstract Our objective was to assess whether the harvest processing equipment sanitation practices in beef processing plants are sufficient to mitigate pathogen transfer. Multiple regulatory agencies across the globe require that harvest equipment be sanitized using hot water at a minimum of 82°C, with a momentary dip when a time is specified. Consequently, hot water sanitizers have been widely implemented at meat processing facilities, in particular, for knife sanitation throughout the dressing process. However, there is no standard time requirement for hot water immersion and, as such, the effectiveness of hot water sanitization is uncertain. The practice for knife sanitation at a large beef processing facility was audited and the microbial reduction that simulated the audited practice was assessed along with a momentary dip at 82°C. A five-strain cocktail of Escherichia coli and 11 knives of differing degree of usage obtained from the beef plant were used in the study. An area of 50 cm2 of the upper surface of each knife was spread-inoculated with the five-strain E. coli cocktail and the knife was subsequently submerged in a water bath coupled to a water circulator for immersion at 82°C. Exposures times tested were those derived from the in-plant audit for each knife type. A knife that was similarly inoculated, but was not treated with hot water, served as a positive control. E. coli surviving the treatment were enumerated by plating. In addition, two knives that had most and least reduction of E. coli were artificially contaminated with meat prior to inoculation, by passing the knife through meat multiple times. For each condition, three independent trials were conducted. Least-squares means for log counts were separated by a post-hoc Tukey test. Mean immersion times for different knives audited ranged from 1 to 9.8 s. Immersing knives in water at 82°C significantly reduced the number of E. coli (P < 0.05; Table 1), ranging from 2.3 (air knife)-5.5 (skinning knife 2) log units. Variation among the same knife type was observed. Momentary dip at 82°C reduced E. coli on de-boning, hook, air knife and wizard knife by 1-1.2 log (P < 0.05) and < 1 log for the other six knives (P ≥ 0.05). Treatment at 82°C for the duration of average exposure time observed during the in-plant audit of knives that had been contaminated with meat debris showed lower reductions of E. coli, compared with clean knives. Those reductions (>1.5 log units) were significant (P < 0.05). In conclusion, the duration for hot water sanitation of knives at beef processing plants achieves significant reduction of E. coli if temperature is maintained at 82°C and a momentary dip at the same temperature would be less likely to be effective.