J. D. Tatum

National Beef Quality Audit-2000: survey of targeted cattle and carcass characteristics related to quality, quantity, and value of fed steers and heifers.

The National Beef Quality Audit-2005 assessed the current status of quality and consistency of US fed steers and heifers. Hide colors or breed type were black (56.3%), red (18.6%), Holstein (7.9%), gray (6.0%), yellow (4.9%), brown (3.0%), white (2.3%), and brindle (1.0%). Identification method and frequency were lot visual tags (63.2%), individual visual tags (38.7%), metal-clip tags (11.8%), electronic tags (3.5%), bar-coded tags (0.3%), by other means (2.5%), and without identification (9.7%). Brand frequencies were no (61.3%), 1 (35.1%), and 2 or more (3.6%), and brands were located on the butt (26.5%), side (7.4%), and shoulder (1.2%). There were 22.3% of cattle without horns, and the majority of those with horns (52.2%) were between 2.54 and 12.7 cm in length. Percentages of animals with mud or manure on specific body locations were none (25.8%), legs (61.4%), belly (55.9%), side (22.6%), and top-line (10.0%). Permanent incisor number and occurrence were zero (82.2%), 1 (5.2%), 2 (9.9%), 3 (0.4%), 4 (1.2%), 5 (0.1%), 6 (0.3%), 7 (0.0%), and 8 (0.7%). Most carcasses (64.8%) were not bruised, 25.8% had one bruise, and 9.4% had multiple bruises. Bruise location and incidence were round (10.6%), loin (32.6%), rib (19.5%), chuck (27.0%), and brisket, flank, and plate (10.3%). Condemnation item and incidence were liver (24.7%), lungs (11.5%), tripe (11.6%), heads (6.0%), tongues (9.7%), and carcasses (0.0%). Carcass evaluation revealed these traits and frequencies: steer (63.7%), heifer (36.2%), bullock (0.05%), and cow (0.04%) sex classes; dark-cutters (1.9%); A (97.1%), B (1.7%), and C or older (1.2%) overall maturities; and native (90.9%), dairy-type (8.3%), and Bos indicus (0.8%) estimated breed types. Mean USDA yield grade (YG) traits were USDA YG (2.9), HCW (359.9 kg), adjusted fat thickness (1.3 cm), LM area (86.4 cm(2)), and KPH (2.3%). The USDA YG were YG 1 (16.5%), YG 2 (36.3%), YG 3 (33.1%), YG 4 (11.8%), and YG 5 (2.3%). Mean USDA quality grade traits were USDA quality grade (Select(90)), marbling score (Small(32)), overall maturity (A(64)), lean maturity (A(57)), and skeletal maturity (A(68)). Marbling score distribution was Slightly Abundant or greater (2.7%), Moderate (4.3%), Modest (14.4%), Small (34.5%), Slight (41.2%), and Traces or less (2.9%). This information helps the beef industry measure progress and provides a benchmark for future educational and research activities.

Bos indicus-cross feedlot cattle with excitable temperaments have tougher meat and a higher incidence of borderline dark cutters

Temperament ratings based on a numerical scale (chute score) were assessed during weighing and handling of cattle at a feedlot. Breeds studied included Braford, Red Brangus and Simbrah. Cattle were fed to a constant fat thickness of 9 to 13 mm (target = 11 mm) over the 12th rib as determined by periodic ultrasound measurements. Cattle were slaughtered in a commercial slaughter plant and stunned by captive bolt. Temperament rating had a significant effect on the incidence of borderline dark cutters which were downgraded by a USDA grader (P = 0.01). Temperament score also had a significant effect on tenderness (P < 0.001) as evaluated by Warner-Bratzler Shear (WBS) force at day 14 post mortem. The calmest animals which stood still when restrained in a hydraulic squeeze chute had a mean WBS force of 2.86 ± 11 kg and cattle which became highly agitated and struggled violently during restraint averaged 3.63 ± 19 kg. Forty percent of these cattle had WBS force values which were over 3.9 kg which is a threshold value for acceptability in food service establishments. These data show that cattle with the most excitable temperament ratings produce carcasses with tougher meat and a higher incidence of borderline dark cutters than cattle with calm temperament ratings.

Feeder Cattle Health Management: Effects on Morbidity Rates, Feedlot Performance, Carcass Characteristics, and Beef Palatability1,2

Abstract The effects of morbidity, defined as hospital visits per calf during the feeding period, on feedlot performance, carcass characteristics, and beef palatability traits were determined using 273 steer calves originating from one of two preconditioning programs or auction barns. Cattle treated more than once at the feedyard had a 12% lower ADG through reimplant (67 d; P 0.05) were noted in the effects of hospital visits or preconditioning treatments on beef tenderness and palatability measures. Overall, morbidity resulted in economic losses as a result of mortality and increased costs associated with hospital treatment. Morbidity also decreased (P

Relationships of behavioral and physiological symptoms of preslaughter stress to beef longissimus muscle tenderness

Relationships between behavioral and physiological symptoms of preslaughter stress and LM Warner-Bratzler shear force (WBSF) were investigated using Bos taurus steers (n = 79) and heifers (n = 77). Measurements of heart rate, respiration rate, rectal temperature, and concentrations of serum cortisol and plasma epinephrine were used as indicators of stress associated with physical handling and chute restraint, whereas concentrations of cortisol, glucose, lactate, and creatine kinase in blood samples obtained at exsanguination were measured to reflect physiological reactions of animals to transportation stress. Increased plasma epinephrine concentration, indicative of acute handling stress, was associated with elevated heart rate (r = 0.42, P < 0.001) and rectal temperature (r = 0.34, P < 0.001) during restraint, increased plasma lactate (r = 0.22, P = 0.006) and serum creatine kinase (r = 0.28, P < 0.001) concentrations at slaughter, and greater LM WBSF (r = 0.22, P = 0.006). Plasma lactate concentration at slaughter, which reflected an adrenergic stress response to transportation, was associated with lesser final LM pH (r = -0.30, P < 0.001) and greater LM WBSF (r = 0.26, P = 0.002). Categorical analyses of chute and posttransportation behavior scores (calm vs. restless vs. nervous) showed that cattle exhibiting adverse behavioral reactions to handling and chute restraint had increased (P < 0.05) values for plasma epinephrine concentration, heart rate, and rectal temperature during chute restraint, elevated (P < 0.05) plasma lactate concentration at slaughter, and increased (P < 0.05) LM WBSF. In addition, cattle showing behavioral symptoms of stress after transportation had greater (P < 0.05) plasma glucose and lactate concentrations at slaughter and produced LM steaks that were 0.34 kg tougher (P < 0.05) when compared with calm cattle. No carcasses were identified as dark cutters, and LM pH did not differ (P > 0.05) among behavior categories. Grouping cattle according to differences in plasma lactate concentration categorized them according to mean differences in LM WBSF. Moreover, steaks from cattle with the greatest plasma lactate concentrations at slaughter (91st to 100th percentile) had a delayed response to aging that persisted until 14 d postmortem. Stress-induced differences in LM tenderness observed in this study were independent of differences in muscle pH.

Effectiveness of USDA instrument-based marbling measurements for categorizing beef carcasses according to differences in longissimus muscle sensory attributes1

This study quantified relationships between USDA instrument marbling measurements and LM sensory attributes (tenderness, flavor, juiciness), and shear force. Heifer (n = 390) and steer (n = 328) carcasses (all A-maturity) were selected at 4 beef processing plants in Colorado, Kansas, Nebraska, and Texas to represent 7 marbling degrees: traces (TR), slight (SL), small (SM), modest (MT), moderate (MD), slightly abundant (SA), and moderately abundant (MA). Classification into marbling groups was based on marbling scores determined using USDA-approved VBG 2000 grading systems. Strip loin steaks were obtained from both sides of each carcass and aged for 14 d. One steak was used to obtain Warner-Bratzler shear force (WBSF) and slice shear force (SSF) measurements. The other steak was evaluated by a trained sensory panel for juiciness, tenderness, intensity of flavors characterized as meaty/brothy, buttery/beef fat, bloody/serumy, livery/organy, and grassy; and overall sensory experience (negative or positive). Instrument marbling score explained 45%, 40%, 32%, 71%, and 61% of the observed variation in panel ratings for juiciness, tenderness, meaty/brothy flavor intensity, buttery/beef fat flavor intensity, and overall sensory experience, respectively. Increased degree of marbling resulted in steaks having greater (P < 0.001) juiciness (MA > SA > MD > MT > SM > SL = TR), meaty/brothy flavor (MA = SA > MD = MT > SM > SL > TR), and buttery/beef fat flavor (MA > SA > MD > MT > SM > SL > TR). Steak tenderness also increased (P < 0.001) as marbling degree increased; however, tenderness differences among marbling degrees differed for steers (MA = SA > MD = MT > SM > SL = TR) and heifers (MA = SA > MD > MT > SM > SL > TR). Steaks produced by steers had lower (P < 0.05) WBSF and SSF values, and were rated as more tender by sensory panelists than steaks produced by heifers, but the effect of sex on panel tenderness was significant only among steaks with TR marbling. Results of this study showed that instrument-based classification of beef carcasses, according to differences in marbling, effectively identified subsequent differences in strip loin steak sensory performance. Nearly all (98 to 99%) steaks with MA or SA marbling, and most (between 80% and 90%) steaks with MD and MT marbling, received positive ratings for overall sensory experience. In comparison, 62% of SM steaks, 29% of SL steaks, and 15% of TR steaks received positive sensory experience ratings.

Palatability of Beef Steaks Marinated with Solutions of Calcium Chloride, Phosphate, and (or) Beef-Flavoring

This study evaluated the efficacy of marination for increasing consumer acceptability of beef. Top-sirloin steaks from 28 USDA select steers were randomly assigned to one of six marination treatments: control (CT), 150 mM calcium chloride (CA), 10% solution of beef-flavoring/seasoning mixture (FL), CA and FL (CF), 2.5% sodium phosphate and FL (PF), and tap water (TW). Steaks were marinated in vacuum pouches, aged for 7 days, cooked to 70°C and evaluated by a trained sensory panel. Marination with CA did not affect tenderness ratings, but increased (P<0.05) bitter and metallic flavors compared to CT or TW treatments. Use of FL, alone or in conjunction with CA or sodium phosphate, increased (P<0.05) tenderness and juiciness ratings and reduced (P<0.05) bitterness and metallic flavors compared to CT, CA and TW marinades. Marination of beef, in vacuum pouches, is an effective method for increasing consumer acceptability and value beef.

Microbial Contamination Occurring on Lamb Carcasses Processed in the United States

Lamb carcasses (n = 5,042) were sampled from six major lamb packing facilities in the United States over 3 days during each of two visits (fall or winter, October through February; spring, March through June) in order to develop a microbiological baseline for the incidence (presence or absence) of Salmonella spp. and for populations of Escherichia coli after 24 h of chilling following slaughter. Samples also were analyzed for aerobic plate counts (APC) and total coliform counts (TCC). Additionally, incidence (presence or absence) of Campylobacter jejuni/coli on lamb carcasses (n = 2,226) was, determined during the slaughtering process and in the cooler. All samples were obtained by sponge-sampling the muscle-adipose tissue surface of the flank, breast, and leg of lamb carcasses (100 cm2 per site; 300 cm2 total). Incidence of Salmonella spp. in samples collected from chilled carcasses was 1.5% for both seasons combined, with 1.9% and 1.2% of fall or winter and spring samples being positive, respectively. Mean (log CFU/cm2) APC, TCC, and E. coli counts (ECC) on chilled lamb carcasses across both seasons were 4.42, 1.18, and 0.70, respectively. APC were lower (P < 0.05) in samples collected in the spring versus fall or winter, while TCC were higher in samples collected in the spring. There was no difference (P > 0.05) between ECC from samples collected in the spring versus winter. Only 7 out of 2,226 total samples (0.3%) tested positive for C. jejuni/coli, across all sampling sites. These results should be useful to the lamb industry and regulatory authorities as new regulatory requirements for meat inspection become effective.

Effects of ractopamine and trenbolone acetate implants with or without estradiol on growth performance, carcass characteristics, adipogenic enzyme activity, and blood metabolites in feedlot steers and heifers

Two experiments were conducted to evaluate effects of ractopamine (RAC) and steroidal implant treatments on performance, carcass traits, blood metabolites, and lipogenic enzyme activity in feedlot cattle. In Exp. 1, yearling steers (n = 486; initial BW = 305 kg) were used in a 3 × 3 factorial arrangement of RAC doses of 0 (R0), 100 (R100), or 200 (R200) mg·steer(-1)·d(-1) fed for 28 d and implant regimens (implant-reimplant) of no implant-no reimplant (NI-NI), 120 mg of trenbolone acetate (TBA) and 24 mg of estradiol-17β (E17B)-no implant (RS-NI), or 80 mg of TBA and 16 mg of E17B followed by 120 mg of TBA and 24 mg of E17B (RI-RS). Except for KPH and skeletal maturity score, no RAC × implant interactions were noted (P > 0.10). Carcasses from R200 were 6.3 kg (P = 0.042) heavier than those from R0. Marbling, calculated empty body fat (EBF), and USDA quality grade did not differ (P > 0.10) among RAC treatments. The RI-RS steers had 12.6 kg (P = 0.001) and 41.1 kg (P < 0.001) greater HCW than RS-NI and NI-NI, respectively. Despite no difference (P > 0.10) in EBF, marbling score was decreased for RI-RS (P < 0.001) and RS-NI (P = 0.001) relative to NI-NI, resulting in 14.6 and 11.4 percentage unit fewer USDA Prime and Choice carcasses with RI-RS (P = 0.008) and RS-NI (P = 0.039) than with NI-NI. In Exp. 2, heifers (n = 48; initial BW = 347 kg) were used in a 3 × 2 factorial arrangement of RAC doses of 0 (R0) or 250 (R250) mg·heifer(-1)·d(-1) and implant regimens of none (NI), 200 mg of TBA (TO), or 200 mg of TBA and 20 mg of E17B (TE). Blood samples were collected at various times during the feeding period, and subcutaneous adipose samples were collected on d 119. For growth and carcass measurements, no RAC × implant interactions (P > 0.10) were detected. The RAC-supplemented heifers had greater HCW (P < 0.10) with no difference in marbling score. For implant regimens, TE heifers had greater HCW than the NI (P = 0.001) and TO (P = 0.037) heifers. Although EBF did not differ among implant treatments (P > 0.10), TE (P = 0.021) and TO (P = 0.039) had fewer Choice carcasses than NI. Heifers with implants had decreased cortisol and increased IGF-1 and NEFA (P < 0.10) compared with NI heifers. An implant × RAC interaction was detected (P = 0.001) for serum urea nitrogen (SUN), with TE and RAC-supplemented heifers having decreased SUN. These data suggest that the effects of implant and RAC on growth and carcass traits are independent and that USDA quality grade and marbling score can differ significantly among carcasses with similar calculated EBF values.

International perspective: characterisation of United States Department of Agriculture and Meat Standards Australia systems for assessing beef quality

The intent, in this manuscript, is to characterise the United States Department of Agriculture (USDA) and Meat Standards Australia (MSA) systems for assessing beef quality and to describe the research evidence that supports the principles involved in grade application. USDA beef quality grading standards rely on carcass-trait-only assessments of approximate age of the animal at harvest and amount of intramuscular fat (as marbling) inside the muscles. USDA beef quality grading started 82 years ago. Then, as now, because no traceability system was in place, each animal’s history (exact age, feeding regimen, management practices, etc.) was incomplete; those who assigned quality grades used indicators of age (physiological maturity) and plane of nutrition (amount of marbling), and they do so still. Since 1926, research studies have identified a multitude of palatability-determining live-animal factors (e.g. genetics, use of hormonal growth promotants, high-energy diet finishing) and carcass-treatment factors (e.g. electrical stimulation, tenderstretch carcass suspension, postmortem aging) that cannot be incorporated into a carcass-trait-only quality assessment system. The USA beef industry has depended on development of more than 100 beef brands – some using palatability assurance critical control point plans, total quality management (TQM) philosophies, USDA certification and process verification programs, or combinations of live-animal factors, carcass-treatment factors and carcass-trait constraints – to further differentiate fresh beef products. The MSA grading system is a TQM grading approach that incorporates animal-specific traits (e.g. genetics, sex, age), control of certain pre-harvest and post-harvest processes in the beef chain, cut-specific quality differences and consumer preferences, into a beef pricing system. A unique aspect of the MSA grading system is that the grades are assigned to cuts or muscles, not carcasses; cuts or muscles from the same carcass are assigned individual (and in many cases, different) grades that reflect differences in expected eating quality performance among the various cuts of beef further adjusted to reflect the influence of cut or muscle aging and alternative cooking methods. The MSA grading system is still being modified and refined (using results of an extensive, ongoing consumer testing program), but it represents the best existing example of a TQM grading approach for improving beef quality and palatability. Research studies have shown that the accuracy of palatability-level prediction by use of the two systems – USDA quality grades for US customers and consumers and MSA grades for Australian customers and consumers – is sufficient to justify their continued use for beef quality assessment.

National Beef Quality Audit-2011: Harvest-floor assessments of targeted characteristics that affect quality and value of cattle, carcasses, and byproducts.

The National Beef Quality Audit-2011 (NBQA-2011) was conducted to assess targeted characteristics on the harvest floor that affect the quality and value of cattle, carcasses, and byproducts. Survey teams evaluated approximately 18,000 cattle/carcasses between May and November 2011 in 8 beef processing facilities. Cattle identification methods were lot visual tags (85.7%), individual visual tags (50.6%), electronic tags (20.1%), metal-clip tags (15.7%), other (5.3%), none (2.5%), and wattles (0.5%). Hide colors or breed types were black (61.1%), red (12.8%), yellow (8.7%), Holstein (5.5%), brown (5.0%), gray (5.0%), white (1.4%), and brindle (1.0%). Brand frequencies were none (55.2%), 1 (40.4%), 2 (4.4%), and 3 or more (0.04%) brands, and brands were located on the butt (35.2%), side (9.0%), and shoulder (2.5%). Hide locations of mud or manure were no mud/manure (49.2%), legs (36.8%), belly (23.7%), side (14.9%), top-line (11.0%), and tail region (13.7%). There were 76.2% of cattle without horns, and the majority of those with horns (71.6%) were between 0 cm and 12.7 cm in length. Permanent incisor numbers were zero (87.3%), 1 (1.4%), 2 (8.0%), 3 (0.9%), 4 (1.9%), 5 (0.3%), 6 (0.2%), 7 (0.1%), and 8 (0.02%). Most carcasses (77.0%) were not bruised, 18.7% had 1 bruise, 3.4% had 2 bruises, 0.6% had 3 bruises, and 0.3% had more than 3 bruises. Bruise locations were loin (50.1%), rib (21.3%), chuck (13.8%), round (7.3%), and brisket/flank/plate (7.5%). Condemnation item and incidence were whole carcass (none recorded), liver (20.9%), lungs (17.3%), tongue (10.0%), viscera (9.3%), and head (7.2%). Compared with the NBQA-2005, the NBQA-2011 had an increased percentage of black-hided cattle (56.3 vs. 61.1%), more cattle with brands (38.7 vs. 44.8%), and more cattle with some form of identification (93.3 vs. 97.5%). In addition, there was a lesser percentage of carcasses with bruising in 2011 (23.0%) than in 2005 (35.2%), as well as a smaller percentage of carcasses with more than 1 bruise (2005 = 9.4% vs. 2011 = 4.2%). Compared with the 2005 audit, a similar percentage of the cattle were deemed 30 mo of age or older using dentition (2005 = 2.7% vs. 2011 = 3.3%). The information from NBQA-2011 helps the beef industry measure progress against previous NBQA assessments and provides a benchmark for future educational and research activities.