Efficacy of antimicrobial interventions in reducing Salmonella enterica, Shiga toxin-producing Escherichia coli, Campylobacter, and Escherichia coli biotype I surrogates on non-chilled and chilled, skin-on and skinless pork.

Effect of various antimicrobial interventions on pork carcass cuts - skin-on and skinless, non-chilled and chilled - was studied. Carcass pieces were inoculated with Salmonella enterica, Shiga toxin-producing Escherichia coli (STEC), Escherichia coli pathogen surrogates or Campylobacter spp. Inoculated pieces were assigned to one of the following antimicrobial treatments: 2.5% and 5.0% room temperature lactic acid, 2.5% and 5.0% warm (55 °C) lactic acid, 400 ppm (0.4 mg/mL) room temperature peroxyacetic acid (PAA) or warm (55 °C) water. Treated pieces were sampled before antimicrobial treatment of non-chilled pork tissue, then at 30 m and 24 h post-treatment. For chilled pork, samples were collected after 24 h chilling and 30 m post-treatment. Lactic acid and PAA treatments reduced (P < 0.05) pathogenic and surrogate bacteria; warm water did not produce similar results. Objective and sensory color evaluations on treated pork indicated minimal negative impacts on pork color. Various antimicrobial interventions were effective in reducing surrogates on pork without diminishing quality.

Role of lactate dehydrogenase in metmyoglobin reduction and color stability of different bovine muscles.

The role of lactate dehydrogenase (LDH) in metmyoglobin reducing activity (MRA) and color stability of different bovine muscles was studied in two consecutive experiments. In experiment 1, three different bovine muscles -M. longissimus lumborum (LL), M. semimembranosus (SM), and M. psoas major (PM) - were obtained (n=7, respectively), cut into steaks, PVC packaged, and then displayed for 7days at 1°C. The LL was the most red over display time and had more (P<0.05) LDH-B activity (catalyzing toward NADH generation), LDH1 isoform expression, NADH, and higher (P<0.05) MRA than the other two muscles studied. The PM had the least color stability and lowest MRA. In experiment 2, LL steaks (n=8) were cut in half, one side syringe-injected with oxamate, and the other injected with distilled water. Inclusion of oxamate decreased (P<0.05) LDH-B activity, NADH, and a* values after 10days display at 1°C. These results suggest that variation in color stability of physiologically different muscles is regulated by different replenishment rates of NADH via different LDH isozymes.

Color stability and biochemical characteristics of bovine muscles when enhanced with L- or D-potassium lactate in high-oxygen modified atmospheres.

Two different bovine muscles -M.longissimus lumborum (LD) and M. psoas major (PM) - were injection-enhanced (n=10, respectively) with solutions containing phosphate and potassium L- or D-lactate, cut into steaks, packaged with a high-oxygen (80% O(2)) modified atmosphere packaging, stored 9d at 2°C and then displayed for 5d at 1°C. Instrumental color, total reducing activity (TRA), lactate dehydrogenase (LDH) activity, and NADH were measured. Enhancement with L-lactate resulted in less color deterioration, and higher a(∗) and chroma values (P<0.05) than non-enhanced control of the bovine muscles. L-lactate enhancement significantly increased NADH concentration and TRA of LD and PM than the non-enhanced control through increased LDH-B flux at 14d. This study presents supportive evidence that the lactate-LDH system remains active for muscles with different metabolic activities and may be a possible mechanism of the lactate-color stabilization effect. Further, L-lactate enhancement can be utilized for improving muscles with lower color stability in high-oxygen modified atmosphere.

Influence of transportation stress and animal temperament on fecal shedding of Escherichia coli O157:H7 in feedlot cattle.

To test the influence of transportation stress and temperament on shedding of Escherichia coli O157:H7, cattle (n=150) were classified at various stages of production as Excitable, Intermediate or Calm based on a variety of disposition scores. Presence of E. coli O157:H7 was determined by rectal swabs from live animals and from colons collected postmortem. Percentage of cattle shedding E. coli O157:H7 at arrival at the feedlot was approximately equal among temperament groups. Before shipment to the processing facility, a higher (P=0.03) proportion of cattle from the Calm group shed E. coli O157:H7 compared to the other temperament groups. When pooled across all sampling periods, cattle from the Calm group had a greater percentage test positive for E. coli O157:H7. Neither the acute stressor of transportation nor a more excitable temperament led to increased shedding of E. coli O157:H7 in cattle.

National Beef Market Basket Survey - 2006: External fat thickness measurements and separable component determinations for beef from US retail establishments.

A market basket survey for beef retail cut composition at the retail level (four stores each from two chains in each city) was conducted in 11 US cities from January to March 2006. Beef cuts (n=17,495) were measured for external fat thickness with cuts from the chuck (0.05cm), round (0.05cm), and miscellaneous (0.04cm) having less (P<0.05) fat than cuts from the loin (0.11cm) and rib (0.11cm). Beef cuts (n=1327) were separated physically into separable components with round cuts having more (P<0.05) separable lean (96.63%) than chuck cuts (86.81%) and miscellaneous cuts (86.18%), which had more (P<0.05) separable lean than loin cuts (84.53%) with rib cuts (69.34%) having the lowest (P<0.05) separable lean. Chemical fat from the separable lean differed (P<0.05) between each cut category: round cuts (3.71%), miscellaneous cuts (4.99%), loin cuts (5.60%), chuck cuts (6.90%), and rib cuts (8.61%). Ground beef samples (n=235), with declared lean/fat percentages ranging from 73/27 to 96/4, had overall chemical fat values of 13.41% and moisture values of 67.42%. This survey documents the current beef retail cut and ground beef composition, which is helpful to those who need this information for various dietary and marketing purposes.

Dry versus wet aging of beef: Retail cutting yields and consumer palatability evaluations of steaks from US Choice and US Select short loins.

Paired beef short loins from US Choice (n=48) and US Select (n=48) carcasses were assigned to be dry or wet aged for 14, 21, 28 or 35d. After aging, short loins were processed to determine retail yields and processing times. Upon completion of cutting tests, steaks were served to consumers to assess palatability characteristics. Retail cutting tests showed that dry-aged short loins had reduced yields and increased cutting times when compared to wet-aged short loins. Consumers were unable to determine differences between dry- and wet-aged steaks and for aging periods; however, USDA quality grade had a significant impact on consumer perception of palatability attributes.

Identifying muscle and processing combinations suitable for use as beef for fajitas.

Four different treatments-control, papain, blade tenderization, and papain+blade tenderization-were applied to sixty USDA Choice M. diaphragma pars costalis, M. transversus abdominis, M. obliquus abdominis internus, M. rhomboideus, M. trapezius, M. latissimus, and M. serratus ventralis. Trained (n=6) and consumer (n=81) panelists scored papain samples higher for most sensory traits. Treatment tended not to affect the palatability scores of the M. diaphragma pars costalis and M. serratus ventralis, which tended to receive higher scores in comparison to the other muscles. Consumers were willing to purchase the M. latissimus and M. serratus ventralis treated with papain+blade tenderization and papain, respectively, and these muscles performed well enough to be considered as alternatives in the beef fajita market.

Dry versus wet aging of beef: Retail cutting yields and consumer sensory attribute evaluations of steaks from ribeyes, strip loins, and top sirloins from two quality grade groups.

Top Choice (n=48) and Select (n=48) paired bone-in ribeye rolls, bone-in strip loins, and boneless top sirloin butts were assigned randomly to one of two aging treatments, dry or wet, and were aged for 14, 21, 28 or 35d. Cutting tests, performed to determine retail yields and processing times, showed dry-aged subprimals had lower total saleable yield percentages and increased processing times compared to wet-aged subprimals. Sensory and Warner-Bratzler shear evaluation was conducted to determine palatability characteristics. For the most part, aging treatment and aging period did not affect consumer sensory attributes. However, ribeye and top loin steaks from the Top Choice quality grade group received higher sensory ratings than their Select counterparts. For top sirloin steaks, no consumer sensory attributes were affected by aging treatment, aging period, or quality grade group.

Comparison of Salmonella Prevalence Rates in Bovine Lymph Nodes across Feeding Stages.

Peripheral lymph nodes (LNs) located in the fatty tissues of beef carcasses have been shown to harbor Salmonella and, thus, potentially contaminate ground beef. Salmonella prevalence within LNs is known to differ among feedlots. Two South Texas feeding operations (identified as locations A and B) known to harbor salmonellae in the feedlot environment, while historically producing cattle with opposing rates (one "high" and one "low") of Salmonella prevalence in LNs, were used in this study. To determine whether this difference was due to cattle source or factors associated with different stages of feeding, weanling steers of common and known origin were followed through normal feeding stages at both operations. Eighty Angus-sired beef steers were harvested at each of four feeding stages: 1, postweaning; 2, background or stocker; 3, 60 days on feed; and 4, 120 days on feed. Left and right subiliac and superficial cervical LNs ( n = 304) were collected from each carcass, and similar node types were pooled by animal ( n = 152). Results showed a difference ( P < 0.05) in prevalence of Salmonella in bovine lymph nodes between location A and location B and among feeding stages in location B. Salmonella was not isolated from any feeding stage 1 (postweaning) or location A LN samples. Within location B, there was an increase in Salmonella prevalence as cattle moved into later stages of feeding: at 22.2% (4 of 18), 77.8% (14 of 18), and 94.4% (17 of 18) for feeding stages 2, 3, and 4, respectively. Although the reasons for the differences seen between feeding operations and for increased Salmonella prevalence in LNs at later feeding stages remain unexplained, these results indicate that factors other than cattle source are likely influencing Salmonella prevalence in LNs.

Effects of oral vitamin D(3) supplementation and supplement withdrawal on the accumulation of magnesium, calcium, and vitamin D in the serum, liver, and muscle tissue and subsequent carcass and meat quality of Bos indicus influenced cattle.

Bos indicus crossbred cattle (n=79) were fed vitamin D(3) (0 or 3 million IU/hd/d) for 5d. Afterwards, half of each group was slaughtered immediately, while half was fed, without supplementation, for 7d before processing. Serum calcium concentration was increased (P<0.05) in cattle after supplement removal, but not immediately following supplementation. This also was observed in the M. longissimus lumborum and M. triceps brachii, but not in the M. semitendinosus. Liver biopsy vitamin D(3) concentrations were higher (P<0.05) in supplemented cattle immediately following supplementation, but were not different from controls after supplement removal. Vitamin D(3) did not affect tenderness at supplement removal day 0, but increased the tenderness of the M. longissimus lumborum and M. semitendinosus at supplement removal day 7. Vitamin D(3) supplementation improves muscle tenderness and may be more effective when supplementation is ceased 7d before slaughter, with minimum food safety concerns.

National beef tenderness survey - 2006: Assessment of Warner-Bratzler shear and sensory panel ratings for beef from US retail and foodservice establishments.

Beef from retail and foodservice establishments in 11 US cities was evaluated using Warner-Bratzler shear (WBS) and consumer evaluation panels. Postmortem aging times ranged from 3 to 83d for retail and 7 to 136d for foodservice with mean aging times of 22.6d and 30.1d, respectively. For retail, the three cuts from the round - top round, bottom round, and eye of round - had the highest (P<0.05) WBS values compared to cuts from the chuck, rib, and loin. Top loin steaks had the lowest (P<0.05) WBS value compared to ribeye and top sirloin foodservice steaks. Retail bone-in top loin, top loin, ribeye, T-bone, and porterhouse received the highest (P<0.05) ratings by consumers for overall like and like tenderness. Quality grade had little or no effect on foodservice sensory evaluations. Improvements in round tenderness are needed to increase consumer acceptability.

National Beef Quality Audit-2016: Phase 1, Face-to-face interviews.

The National Beef Quality Audit (NBQA) is conducted every 5 yr and was most recently again conducted in 2016. Face-to-face interviews gauged progress in quality associated with live cattle production using procedures first utilized in NBQA 2011. The 2016 NBQA was the first in which interviews concerning fed steers and heifers were combined with an audit of market cow and bull beef. Face-to-face interviews were designed to illicit definitions for beef quality, estimate willingness to pay (WTP) for quality attributes, establish relative importance rankings for important quality factors, and assess images, strengths, weaknesses, potential threats, and shifting trends in the beef industry since the 2011 audit. Individuals making purchasing decisions in 5 market sectors of the steer/heifer and cow/bull beef supply chain were interviewed, including packers (n = 36), retailers (including large and small supermarket companies and warehouse food sales companies; n = 35), food service operators (including quick-serve, full-service, and institutional establishments; n = 29), further processors (n = 64), and peripherally-related government and trade organizations (GTO; n = 30). Face-to-face interviews were conducted between January and November of 2016 using a designed dynamic routing system. Definitions (as described by interviewees) for 7 pre-determined quality factors, including: (1) How and where the cattle were raised, (2) Lean, fat, and bone, (3) Weight and size, (4) Visual characteristics, (5) Food safety, (6) Eating satisfaction, and (7) Cattle genetics were recorded verbatim and categorized into similar responses for analysis. Compared to NBQA-2011, a higher percentage of companies were willing to pay premiums for guaranteed quality attributes, but overall were willing to pay lower average premiums than the companies interviewed in 2011. Food safety had the highest share of preference among all interviewees, generating a double-digit advantage over any other quality factor. The 2 beef industries have an overall positive image among interviewees, and despite lingering weaknesses, product quality continued to be at the forefront of the strengths category for both steer and heifer beef and market cow and bull beef.

National Beef Quality Audit-2016: Transportation, mobility, and harvest-floor assessments of targeted characteristics that affect quality and value of cattle, carcasses, and by-products.

The National Beef Quality Audit-2016 (NBQA-2016) was conducted to assess current transportation, mobility, and quality characteristics of U.S. fed steers and heifers. Data were collected at 17 beef processing facilities between March and November 2016. About 8,000 live cattle were evaluated for transportation and mobility, and about 25,000 carcasses were evaluated on the slaughter floor. Cattle were in transit to the slaughter facility for a mean duration of 2.7 h from a mean distance of 218.5 km using trailers with dimensions ranging from 17.84 m2 to 59.09 m2. Area allotted per animal averaged 1.13 m2 and ranged from 0.85 m2 to 2.28 m2. A total of 96.8% of cattle received a mobility score of 1 (walks easily, no apparent lameness). Identification types (35.1% had multiple) were lot visual tags (61.5%), individual tags (55.0%), electronic tags (16.9%), metal-clip tags (9.2%), bar-coded tags (0.05%), wattles (0.01%), and other (2.6%). Cattle were black-hided (57.8%), Holstein (20.4%), red-hided (10.5%), yellow-hided (4.8%), gray-hided (2.9%), brown-hided (1.3%), and white-hided (1.1%). Unbranded hides were observed on 74.3% of cattle; 18.6% had brands located on the butt, 6.3% on the side, and 1.3% on the shoulder (values exceed 100% due to multiple brands). For hide-on carcasses, 37.7% displayed no mud or manure; specific locations for mud or manure were legs (40.8%), belly (33.0%), tail region (15.5%), side (6.8%), and top-line (3.9%). Cattle without horns represented 83.3% of the sample, and cattle that did have horns measured: < 2.54 cm (5.5%), 2.54 to 12.7 cm (8.3%), and > 12.7 cm (2.9%). Carcasses without bruises represented 61.1% of those sampled, whereas 28.2% had 1, 8.2% had 2, 2.1% had 3, and 0.3% had 4 bruises. Of those carcasses with a bruise, the bruise was located on the loin (29.7%), round (27.8%), chuck (16.4%), rib (14.4%), and brisket/plate/flank (11.6%). Frequencies of offal condemnations were livers (30.8%), lungs (18.2%), viscera (16.3%), hearts (11.1%), heads (2.7%), and tongues (2.0%). Compared to NBQA-2011, fewer cattle were identified for traceability, fewer were black-hided, a greater number were Holstein cattle, more with no brand and no horns, fewer without bruises, more liver, lung, and viscera condemnations, and fewer heads and tongues were condemned. The NBQA remains an influential survey for the U.S. beef industry to provide benchmarks and strategic plans for continued improvement of beef quality and consistency.

National Beef Quality Audit-2016: Transportation, mobility, live cattle, and carcass assessments of targeted producer-related characteristics that affect value of market cows and bulls, their carcasses, and associated by-products.

The National Beef Quality Audit-2016 marks the fourth iteration in a series assessing the quality of live beef and dairy cows and bulls and their carcass counterparts. The objective was to determine the incidence of producer-related defects, and report cattle and carcass traits associated with producer management. Conducted from March through December of 2016, trailers (n = 154), live animals (n = 5,470), hide-on carcasses (n = 5,278), and hide-off hot carcasses (n = 5,510) were surveyed in 18 commercial packing facilities throughout the United States. Cattle were allowed 2.3 m2 of trailer space on average during transit indicating some haulers are adhering to industry handling guidelines for trailer space requirements. Of the mixed gender loads arriving at processing facilities, cows and bulls were not segregated on 64.4% of the trailers surveyed. When assessed for mobility, the greatest majority of cattle surveyed were sound. Since the inception of the quality audit series, beef cows have shown substantial improvements in muscle. Today over 90.0% of dairy cows are too light muscled. The mean body condition score for beef animals was 4.7 and for dairy cows and bulls was 2.6 and 3.3, respectively. Dairy cattle were lighter muscled, yet fatter than the dairy cattle surveyed in 2007. Of cattle surveyed, most did not have horns, nor any visible live animal defects. Unbranded hides were observed on 77.3% of cattle. Carcass bruising was seen on 64.1% of cow carcasses and 42.9% of bull carcasses. However, over half of all bruises were identified to only be minor in severity. Nearly all cattle (98.4%) were free of visible injection-site lesions. Current results suggest improvements have been made in cattle and meat quality in the cow and bull sector. Furthermore, the results provide guidance for continued educational and research efforts for improving market cow and bull beef quality.

National Beef Quality Audit - 2016: Survey of carcass characteristics through instrument grading assessments.

The instrument grading assessment portion of the National Beef Quality Audit (NBQA) - 2016 allows the unique opportunity to evaluate beef carcass traits over the course of a year. One week of instrument grading data was collected each month from 5 beef processing corporations encompassing 18 facilities from January 2016 through December 2016 ( = 4,544,635 carcasses). Mean USDA yield grade (YG) was 3.1 with 1.37 cm fat thickness (FT), 88.9 cm LM area, 393.6 kg HCW, and 2.1% KPH. Frequency distribution of USDA YG was 9.5% YG 1, 34.6% YG 2, 38.8% YG 3, 14.6% YG 4, and 2.5% YG 5. Increases in HCW and FT since the NBQA-2011 were major contributors to differences in mean YG and the (numerically) increased frequency of YG 3, 4, and 5 carcasses found in the current audit. Mean marbling score was Small, and the distribution of USDA quality grades was 4.2% Prime, 71.4% Choice, 21.7% Select, and 2.7% other. Frequency of carcasses grading Prime on Monday (6.43%) was numerically higher than the average frequency of carcasses grading Prime overall (4.2%). Monthly HCW means were 397.6 kg in January, 397.2 kg in February, 396.5 kg in March, 389.3 kg in April, 384.8 kg in May, 385.0 kg in June, 386.1 kg in July, 394.1 kg in August, 399.1 kg in September, 403.9 kg in October, 406.5 kg in November, and 401.9 kg in December. Monthly mean marbling scores were Small in January, Small in February, Small in March, Small in April, Small in May, Small in June, Small in July, Small in August, Small in September, Small in October, Small in November, and Small in December. Both mean HCW and mean marbling score declined in the months of May and June. The month with the greatest numerical frequency of dark cutters was October (0.74%). Comparison of overall data from in-plant carcass and instrument grading assessments revealed close alignment of information, especially for YG (3.1 for in-plant assessment versus 3.1 for instrument grading) and marbling (Small for in-plant assessment versus Small for instrument grading). These findings allow the beef industry access to the greatest volume of beef value-determining characteristics for the U.S. fed steer and heifer population than ever reported, resulting in potentially more precise targeting of future quality and consistency efforts.

National Beef Quality Audit-2016: In-plant survey of carcass characteristics related to quality, quantity, and value of fed steers and heifers.

The National Beef Quality Audit (NBQA)-2016 used in-plant cooler assessments to benchmark the current status of the fed steer and heifer beef industry in the United States. In-plant cooler assessments ( = 9,106 carcasses) were conducted at 30 facilities, where approximately 10% of a single day's production were evaluated for USDA quality grade (QG) and yield grade (YG) factors. Frequencies of evaluated traits were 66.5% steer and 33.4% heifer sex classes and 82.9% native, 15.9% dairy-type, and 1.2% estimated breed types. Mean USDA YG factors were 1.42 cm for adjusted fat thickness, 89.5 cm for LM area, 390.3 kg for HCW, and 1.9% for KPH. Mean USDA YG was 3.1, with a frequency distribution of 9.6% YG 1, 36.7% YG 2, 39.2% YG 3, 12.0% YG 4, and 2.5% YG 5. Mean USDA QG traits were Small for marbling score, A for overall maturity, A55 for lean maturity, and A for skeletal maturity. Mean USDA QG was Select with a frequency distribution of QG of 3.8% Prime, 67.3% Choice, 23.2% Select, and 5.6% lower score. Lower score included dark cutter (1.9%), blood splash (0.1%), and hard bone, which are USDA overall maturity scores of C or older (1.8%). Marbling score distributions were 0.85% Slightly Abundant or greater, 7.63% Moderate, 23.54% Modest, 39.63% Small, 23.62% Slight, and 0.83% Traces or less. Carcasses that were Choice or Select and USDA YG 2 or 3 accounted for 70.7% of the carcasses evaluated. Compared with the previous NBQA, we found a numerical increase in mean USDA YG, USDA QG, adjusted fat thickness, HCW, LM area, and marbling score with an increase in dairy-type carcasses and percentage of carcasses grading USDA Prime and Choice as well as frequency of USDA YG 4 and 5. The findings from this study will be used by all segments of the industry to understand and improve the quality of fed steer and heifer beef that is being produced.

Physical, chemical, and histological characteristics of 18 lamb muscles.

Muscles (n=18) were dissected from each side of 20 lamb carcasses to characterize physical, chemical, and histological traits. Muscles from the right sides were used to measure color values, expressible moisture, pH, total collagen content, and sarcomere length. Muscles from the left sides were aged for 7d and used to determine Warner-Bratzler shear (WBS) force values. The M. adductor and M. semimembranosus had the darkest colored lean (lowest L(∗) values), whereas the M. latissimus dorsi and M. tensor fasciae latae had the lightest colored lean (highest L(∗) values). The M. triceps brachii, M. pectoralis profundus, and M. latissimus dorsi had among the lowest numerical expressible moistures whereas the M. adductor and the M. longissimus lumborum had among the highest. The M. infraspinatus was found to have the highest collagen content (9.0mg/g) and the M. psoas major had the longest sarcomere length (3.1µm). Of the muscles sampled, the M. serratus ventralis had one the lowest WBS values (21.8N) and the M. semimembranosus the highest (42.6N). On average, the largest muscles identified were the M. gluteobiceps, M. gluteus medius, M. longissimus lumborum, M. longissimus thoracis, and M. semimembranosus, which would likely be suitable in terms of physical dimensions for used in a variety of individual muscle applications. Other muscles, however, such as the M. teres major and M. tensor fasciae latae, may be too small in size and dimension to be used for individual application.

Beef hide antimicrobial interventions as a means of reducing bacterial contamination.

This project was designed to evaluate interventions capable of reducing bacterial counts on the hide prior to opening. In Trial I, fresh beef hides (n=12) were cut into sections and assigned to serve as either clipped (hair trimmed) or non-clipped sections. Sections were inoculated with a bovine fecal slurry and sampled following a water wash. Treatments (distilled water, isopropyl alcohol, 3% hydrogen peroxide, 2% l-lactic acid, 10% povidone-iodine, and 1% cetylpyridinium chloride (CPC)) were then applied to each section and the sections were sampled for enumeration of aerobic plate counts (APCs), coliforms, and Escherichia coli. Within clipped samples, 1% CPC and 3% hydrogen peroxide caused the greatest reductions in APCs (4.6 and 4.4 log(10)CFU/100-cm(2), respectively), and 1% CPC, 2% l-lactic acid, and 3% hydrogen peroxide caused the greatest reductions in coliform counts (4.5, 4.1, and 3.9 log(10)CFU/100-cm(2), respectively). In Trial II, beef carcasses with hides on were sampled initially and clipped, and then 2% l-lactic acid, 3% hydrogen peroxide, or 1% CPC were applied before sampling. For APCs, 1% CPC produced the greatest reduction on the hide surface (3.8 log(10)CFU/100-cm(2)). Selective application of these antimicrobials to clipped hide opening sites reduced bacterial counts on hide surfaces, and therefore could reduce final carcass counts in these areas by decreasing the bacterial load before opening.

Carcass merit between and among family groups of Bos indicus crossbred steers and heifers.

Differences in live and carcass traits attributable to increasing Bos indicus breed influence were compared to the differences between families with similar proportions of B. indicus influence. Families of offspring from 1/2 Angus×1/2 B. indicus mated to Angus, B. indicus, and 1/2 Angus×1/2 B.indicus were raised under similar conditions. Average daily gain, slaughter weight, and dressing percentage were measured in addition to USDA yield and quality grade factors. Breed type did not affect average daily gain, slaughter weight, dressing percentage, carcass weight, adjusted 12th-rib fat thickness, estimated percentage kidney, pelvic, and heart fat, or carcass maturity. Predominately (3/4) Angus progeny produced greater (P<0.05) longissimus muscle areas than 3/4 B. indicus animals. Predominately Angus cattle also had greater (P<0.05) marbling scores and USDA quality grades than predominately B. indicus cattle. Families within breed types differed (P<0.05) with regard to all traits measured. This is interesting in light of the lack of differences between breeds for most traits. In some instances, the differences in marbling score and longissimus muscle area between families within a given breed type were similar or greater in magnitude than the differences observed between predominately Angus and predominately B. indicus breed types. Whereas growth and carcass traits varied between levels of B. indicus breeding, the opportunity does exists to improve these traits by selecting within specific family lines.

Retail cutting characteristics for US Choice and US Select beef subprimals.

US Choice (Ch) and US Select (Se) beef subprimals from the rib, chuck, plate, loin, and round were obtained to conduct retail cutting tests. Subprimals were merchandised into bone-in or boneless retail cuts and associated components by experienced retail meat merchandisers. These Se subprimals had less (P<0.05) trimmable fat than their Ch counterparts: ball tip, top sirloin, outside round, inside round, and ribeye. Se inside rounds, outside rounds, eye of rounds, boneless striploins, and ball tips had greater (P<0.05) purge losses than the same cuts from Ch. The only subprimals where grade impacted total saleable yield were the top (inside) rounds (Ch=80.13%, Se=87.34%; P=0.004) and outside rounds cut into roasts, steaks, and cubed steaks (Ch=87.61%, Se=90.28%; P=0.05). Methods to increase retail yields from beef subprimals should consider minimizing purge and increasing cutting efficiencies in addition to reducing fat trim.