Genetic parameters for carcass traits of progeny of beef bulls mated to dairy cows.

Beef × dairy crossbred cattle (n = 615) were used to evaluate the effect of preharvest indicator traits and genotypes on the accuracy of estimated breeding values (EBVs) of seedstock candidates for selection. Genotypes for 100,000 single nucleotide polymorphisms were provided by the American Simmental Association of purebred and crossbred seedstock animals (n = 2,632). Five hundred and ninety-five of the 615 beef × dairy cattle had carcass camera and ultrasound data. Phenotypes were not used for any of the seedstock animals even though some may have had performance and ultrasound data. We estimated the genomic relationship matrix among 3,247 animals including both phenotyped and unphenotyped animals. We computed genetic parameters among 37 traits using 666 bivariate restricted maximum likelihood analyses. The accuracy of EBV depends on heritability. For the sake of brevity, we report accuracy for marbling as a proxy for other traits with similar heritability. We focus on accuracy for marbling because marbling is the primary determinant of carcass value. We computed EBV for all 3,247 animals for marbling based on camera data postharvest using best linear unbiased prediction. We report evidence of overlap in causative genes among postharvest carcass traits; marbling, ribeye area, yield grade, fat thickness, and hot carcass weight (HCW) based on genetic correlations. Genetic correlations range from -0.73 to 0.89. Several live animal traits (frame size, body weight and ultrasound fat thickness and ribeye area) were genetically correlated with postharvest traits; including HCW, ribeye area, yield grade, fat thickness, and marbling. Genetic correlations between pre- and postharvest traits ranged from -0.53 to 0.95. Accuracy for marbling ranged from 0.64 to 0.80 for animals with marbling recorded, and from 0.09 to 0.60 for animals without marbling recorded. The accuracy of animals without phenotypes was related to the genomic relationship between animals with phenotype and those without. Live animal traits were useful for predicting economically important carcass traits based on genetic correlations. The accuracy of EBV for seedstock animals that were not phenotyped was low, but this is consistent with theory, and accuracy is expected to increase with the addition of genotypes and carcass data from beef × dairy animals.

Low-cost genotyping platforms and sexed-semen have enabled the production of high breeding value dairy replacement heifers from a fraction of the herd representing the most elite cows. The remainder of the cow herd can be bred to beef bulls using male-sexed-semen. Camera carcass data postharvest and ultrasound carcass estimates preharvest (live animals) on beef × dairy animals combined with genotypes and ultrasound on seedstock animals may provide an efficient scheme for selecting beef bulls to mate to dairy cows in the future to maximize carcass value of the progeny. Genotypes are needed to link carcass data from previously harvested to seedstock bull selection candidates because pedigree is typically not available for beef × dairy cattle. We report that live animal ultrasound carcass estimates are predictive of postharvest economically important carcass traits. The accuracy of genetic evaluation of selection candidates without recorded carcass traits was low but is expected to increase with more genotypes and phenotypes on beef × dairy cattle. Genotypes, ultrasound estimates, and camera carcass data on thousands of beef × dairy cattle could enable increased accuracy of selection with periodic infusion of new phenotypes from future generations.

Effects of bacterial direct-fed microbial mixtures offered to beef cattle consuming finishing diets on intake, nutrient digestibility, feeding behavior, and ruminal kinetics/fermentation profile.

Effects of bacterial direct-fed microbial (DFM) mixtures on intake, nutrient digestibility, feeding behavior, ruminal fermentation profile, and ruminal degradation kinetics of beef steers were evaluated. Crossbred Angus ruminally cannulated steers (n = 6; body weight [BW] = 520 ±â€…30 kg) were used in a duplicated 3 × 3 Latin square design and offered a steam-flaked corn-based finisher diet to ad libitum intake for 3, 28-d periods. Treatments were 1) Control (no DFM, lactose carrier only); 2) Treat-A (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis), at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50 mg)/animal-daily minimum; and 3) Treat-B, the same DFM combination, but doses at 1:1:3:1 ratio. Bacterial counts were ~30% greater than the minimum expected. Data were analyzed using the GLIMMIX procedure of SAS with the model including the fixed effect of treatment and the random effects of square, period, and animal (square). For repeated measure variables, the fixed effects of treatment, time, and their interaction, and the random effects of square, period, animal (square), and animal (treatment) were used. Preplanned contrasts comparing Control × Treat-A or Treat-B were performed. Intake and major feeding behavior variables were not affected (P ≥ 0.17) by treatments. Steers offered Treat-A had an increased (P = 0.04) ADF digestibility compared with Control. Steers offered Treat-A experienced daily 300 min less (P = 0.04) time under ruminal pH 5.6, a greater (P = 0.04) ruminal pH average and NH3-N concentration (P = 0.05) and tended (P = 0.06) to have a lower ruminal temperature compared to Control. Ruminal VFA was not affected (P ≥ 0.38) by treatments. Steers offered Treat-A increased (P = 0.02) and tended (P = 0.08) to increase the ruminal effective degradable NDF and ADF fractions of the diet-substrate, respectively. When the forage-substrate (low quality) was incubated, steers offered Treat-A tended (P = 0.09) to increase the effective degradable hemicellulose fraction compared to Control. In this experiment, the bacterial combinations did not affect intake and feeding behavior, while the combination with a greater proportion of B. licheniformis (Treat-A) elicited an improved core-fiber digestibility and a healthier ruminal pH pattern, in which the ruminal environment showed to be more prone to induce the effective degradability of fiber fractions, while also releasing more NH3-N.

During the finishing phase, a high-energy diet offers benefits related to beef cattle growth and development. However, it is essential to acknowledge that finisher diets are energy-dense and can pose digestive challenges, such as subacute ruminal acidosis. Digestive disturbances negatively affect animal well-being, growth performance, and economic returns. To address digestive challenges endured by animals on high-energy diets, the current experiment focused on the addition of bacterial direct-fed microbial (DFM) mixtures. A unique combination of bacterial DFM containing Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis was evaluated. These bacteria have been individually reported to improve cattle nutrient utilization, digestibility, ruminal function, and maintain ruminal pH. The study aimed to investigate the effects of this specific microbial combination and doses when added to beef cattle finisher diets. The DFM mixtures offered seemed to not affect intake and major feeding behavior variables. The DFM combination containing a greater proportion of B. licheniformis (Treat-A) seemed to elicit an improved total tract core-fiber digestibility, and a safer ruminal pH pattern. The ruminal environment was shown to be more prone to improve the ruminal effective degradability of fiber fractions, while also releasing more NH3­N.

Effects of bacterial direct-fed microbial combinations on beef cattle growth performance, feeding behavior, nutrient digestibility, ruminal morphology, and carcass characteristics.

The effects of the dietary inclusion of a mixture of bacterial direct-fed microbial (DFM) on feedlot beef cattle growth performance, carcass characteristics, nutrient digestibility, feeding behavior, and ruminal papillae morphology were evaluated. Crossbred-Angus steers (n = 192; initial body weight (BW) = 409 kg ±â€…8 kg) were blocked by BW and randomly assigned into 48 pens (4 steers/pen and 16 pens/treatment) following a randomized complete block design. A steam-flaked corn-based fishing diet was offered to ad libitum intake once daily for 153 d containing the following treatments: (1) Control (no DFM, lactose carrier only); (2) treat-A (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis), at 1:1:1:3 ratio, respectively; totaling 6 × 109 CFU (50 mg)/animal-daily minimum; and (3) treat-B, the same DFM combination, but with doses at 1:1:3:1 ratio. Bacterial counts were ~30% greater than the minimum expected. Data were analyzed using the GLIMMIX procedure of SAS, with pen as the experimental unit, the fixed effect of treatment, and the random effect of BW-block, while preplanned contrasts comparing Control × treat-A or treat-B were used. Steers offered treat-A had increased carcass-adjusted average daily gain (P = 0.03) by 6.7%, gain efficiency (P < 0.01) by 6%, tended (P = 0.07) to have increased carcass-adjusted final BW by 15 kg, and hot carcass weight (P = 0.07) by 10 kg, while treat-B did not differ (P ≥ 0.17) from control. Overall dry matter (DM) intake (P = 0.36) and other carcass traits (P ≥ 0.13) were not affected by treatments. Steers offered treat-A tended to have increased digestibility of DM (P = 0.07) by 3%, neutral detergent fiber (P = 0.10), and hemicellulose (P = 0.08) by 9% compared with control, while treat-B did not differ (P ≥ 0.10) from control. No treatment × period interactions (P ≥ 0.21) or main effects of treatment (P ≥ 0.12) were observed during 24-h feeding behavior. Steers ruminated, ate, chewed, and were more active (P ≤ 0.01) during the second behavioral assessment (day 113), while drinking behavior was not affected (P ≥ 0.88). Ruminal papillae morphology and ruminal ammonia concentration (ruminal fluid collected at slaughter facility) were not affected by treatment (P ≥ 0.39). Steers offered the DFM treat-A had improved growth performance and it positively affected carcass weight and nutrient digestion. The DFM combinations did not seem to affect feedlot cattle feeding behavior or ruminal papillae morphology.

Direct-fed microbials (DFM) are naturally occurring microorganisms that alter cattle ruminal fermentation and intestinal function and have been shown to improve growth performance and nutrient digestibility of cattle. The use of DFM in animal feed has continuously increased in feedlots as an alternative to traditional antibiotic additives, which have gained negative public perception and additional regulatory scrutiny. High-energy diets can induce physiological challenges to cattle, especially when based on high starch availability ingredients, which may negatively affect animal growth performance. Such physiological digestive challenges may be overcome by a target combination of DFM bacterial strains (Lactobacillus animalis, Propionibacterium freudenreichii, Bacillus subtilis, and Bacillus licheniformis). These microorganisms individually have shown to have positive effects on finishing cattle offered high-energy diets, which highlights the need for research to optimize DFM types and doses to enhance the use of bacterial strains that can positively affect cattle growth performance, carcass traits, nutrient digestibility, and other variables relevant to the physiology of digestion. In the current experiment, feedlot steers offered a specific bacterial DFM combination/dose had improved average daily gain and feed efficiency, which were reflected as a positive influence on hot carcass weight and digestibility of nutrients, while not effectcting feeding behavior and ruminal morphology.

A current review of U.S. beef flavor I: Measuring beef flavor.

Historically, consumer acceptance of beef was determined by tenderness. Developments in genetics and management over the last couple of decades have improved tenderness to the point that it is secondary to other factors in beef's taste. Flavor, however, is an extraordinarily complex taste attribute dependent on biological sensors in the mouth, sinus cavity, and jaws. The culinary industry has recently focused on innovative ways to give consumers new products satisfying their curiosity about different foods, especially proteins. Competition from plant-based, cell-based, and even other animal-based proteins provides diversity in consumers' ability to select a protein that satisfies their desire to include unique products in their diet. Consequently, the beef industry has focused on flavor for the last 10 to 15 years to determine whether it can provide the guardrails for beef consumption in the future. The U.S. beef industry formed a Flavor Working Group in 2012 composed of the authors listed here to investigate new and innovative ways to manage and measure beef flavor. The results of this working group have resulted in dozens of papers, presentations, abstracts, and symposia. The objective of this manuscript is to summarize the research developed by this working group and by others worldwide that have investigated methodologies that measure beef flavor. This paper will describe the strengths of the research in beef flavor measurement and point out future needs that might be identified as technology advances.

A current review of U.S. beef flavor II: Managing beef flavor.

Beef flavor continues to be one of the largest drivers of beef demand and a differentiation point of beef from other competing proteins. Tenderness has long been identified as the most important palatability trait for consumer satisfaction. However, as technological advancements and industry practices evolve and improve in response to tenderness management, flavor has emerged as a key driver of consumer satisfaction. In response, the beef industry has recently invested in research focused on beef flavor development, measurement, and management to better understand the factors impacting flavor and help beef maintain this advantage. The current review paper is the second of two such papers focused on summarizing the present knowledge and identifying knowledge gaps. While the other review focuses on current practices related to beef flavor measurement, this review will cover research findings related to beef flavor management. Numerous production and product management factors influence beef flavor. Pre-harvest factors including marbling level, animal genetics/cattle type, diet, and animal age, can influence beef flavor. Moreover, numerous post-harvest product management factors, including product type, aging length and conditions, cookery methods, product enhancement, muscle-specific factors, packaging, retail display factors, and antimicrobial interventions, have all been evaluated for their impact on beef flavor characteristics. Results from numerous studies evaluating many of these factors will be outlined within this review in order to present management and production chain factors that can influence beef flavor.

Body, carcass, and steak dimensions of straightbred Holstein calves and Angus-sired calves from Holstein, Jersey, and crossbred beef dams.

Beef genetics are used with increasing frequency on commercial dairies. Although use of beef genetics improves calf value, variability has been reported in beef × dairy calf phenotype for traits related to muscularity and carcass composition. The objective of this study was to characterize morphometric and compositional differences between beef, beef × dairy, and dairy-fed cattle. Tested treatment groups included Angus-sired straightbred beef steers and heifers (A × B; n = 45), Angus × Holstein crossbreds (A × H; n = 15), Angus × Jersey crossbreds (A × J; n = 16), and straightbred Holsteins (H, n = 16). Cattle were started on trial at mean BW of 302 ±â€…29.9 kg and then fed at 196 ±â€…3.4 d. Morphometric measures were recorded every 28 d during the finishing period, ultrasound measures were recorded every 56 d, and morphometric carcass measures were recorded upon slaughter. Muscle biopsies were collected from the longissimus thoracis of a subset of steers (n = 43) every 56 d. Strip loins were collected from carcasses (n = 78) for further evaluation. Frame size measured as hip height, hip width, and body length was greatest for H cattle (P < 0.05), and A × H cattle had greater hip height than A × J cattle (P < 0.05). Relative to BW as a percentage of mature size, ribeye area of all cattle increased at a decreasing rate (negative quadratic term: P < 0.01), and all ultrasound measures of fat depots increased at an increasing rate (positive quadratic term: P < 0.01). Although no difference was observed in muscle fiber area across the finishing period from the longissimus thoracis (P = 0.80), H cattle had a more oxidative muscle phenotype than A × B cattle (P < 0.05). Additionally, H cattle had the smallest area of longissimus lumborum in the posterior strip loin, greatest length-to-width ratio of longissimus lumborum in the posterior strip loin, and least round circumference relative to round length (P < 0.05). Beef genetics improved muscularity in portions of the carcass distal to the longissimus thoracis.

Divergent selection of beef and dairy breeds has caused differences in skeletal size and muscularity. When calves from dairy systems enter the beef supply chain, variability in mature size and carcass composition are introduced. The objective of this study was to characterize morphometric differences in cattle populations with different proportions of beef and dairy genetics. Body measurements confirmed differences in mature size of beef-type cattle, dairy-type cattle, and beef × dairy cattle; Holstein influence was associated with greater skeletal growth. With advancing maturity, the rate of muscle accretion decreased quadratically while the rate of fat accretion increased quadratically. Although muscularity across all cattle types was similar in the longissimus near the last rib, differences were observed in the posterior end of the strip loin, the forearm, and the round. Differences in mature size, muscularity, and steak dimensions were observed between beef-type cattle, dairy-type cattle, and beef × dairy cattle.

Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on strip loin steak dimensionality, shear force, and sensory attributes.

Carcasses (n = 115) from steers resulting from the mating of four Limousin × Angus sires heterozygous for the F94L myostatin mutation to Jersey, Jersey × Holstein, and Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on strip loin dimensionality, Warner-Bratzler shear force and slice shear force, and sensory panel ratings. In phase I of a two-phase study, 57 carcasses from two sires were utilized to obtain samples of longissimus dorsi (LD), psoas major (PM), gluteus medsius (GM), semitendinosus (ST), serratus ventralis, triceps brachii, and biceps femori muscles, which were vacuum packaged, aged until 10 d postmortem, and frozen. Frozen strip loins were cut into 14, 2.5-cm-thick steaks each, and individual strip loin steaks were imaged at a fixed height on a gridded background and processed through image analysis software. In phase II, to obtain a greater power of test for LD palatability attributes, 58 additional carcasses from three sires were utilized to obtain LD samples only for sensory panel and shear force analysis. Cooked steak sensory attributes evaluated by trained panelists were tenderness, juiciness, beef flavor, browned flavor, roasted flavor, umami flavor, metallic flavor, fat-like flavor, buttery flavor, sour flavor, oxidized flavor, and liver-like flavor. In strip loin steaks from carcasses with one F94L allele, LD muscle area was larger in steaks 4, 5, 7, 8, and 9, and steaks 1, 6, 7, and 9 were less angular than those from carcasses with no F94L allele (P < 0.05). Of the seven muscles observed, there were no shear force differences between F94L genotypes (P > 0.20). F94L genotype did not affect sensory panel ratings of LD and GM steaks (P > 0.07). Cooked ST steaks from carcasses with one F94L rated lower in fat-like flavor compared to those from carcasses with no F94L allele (P = 0.035). Cooked PM steaks from carcasses with one F94L allele rated lower in juiciness, fat-like flavor, buttery flavor, and umami flavor compared to those with no copies of the F94L (P < 0.04). In summary, one copy of the F94L allele utilized in beef × dairy cross steers improved strip loin steak dimensionality, did not affect cooked steak tenderness across seven muscles, and decreased fat-associated flavors in the PM and ST. The use of F94L homozygous terminal beef sires would be an easily implemented strategy for dairy producers to improve steak portion size and shape in carcasses from nonreplacement calves.

In beef × dairy steers, one copy of the F94L allele decreased steak angularity in the strip loin and fat-associated flavor attributes in tenderloin steaks, while tenderness was not impacted. Reduced strip loin steak angularity addresses inherent deficiencies in dairy and dairy-cross carcasses; thus, the F94L allele could improve the consumer and chef acceptability of beef × dairy strip loin steaks. Using a beef sire homozygous for F94L myostatin in a beef-on-dairy system would ensure that all resulting progenies have exactly one copy of the F94L allele, meaning that this genetic strategy could be rapidly implemented in the beef-on-dairy industry segment.

Effects of the F94L myostatin gene mutation in beef × dairy crossed cattle on muscle fiber type, live performance, carcass characteristics, and boxed beef and retail cut yields.

Producer live performance data and carcasses from steers (n = 116) resulting from the mating of four Limousin/Angus sires heterozygous for the F94L myostatin mutation to Jersey/Holstein dams were utilized to evaluate the effects of one copy of the F94L allele on live performance, carcass traits and USDA grades, and boxed beef and retail yields. Slaughter data were collected at time of harvest and carcass data were collected 48 hours postmortem. One side from each of the 58 carcasses was fabricated into boxed beef and retail cuts by experienced lab personnel 5-8 d postmortem. One copy of the F94L allele did not affect gestation length, birth weight, percentage of unassisted births, feedlot average daily gain, live weight at harvest, hot carcass weight, or dressing percentage (P > 0.05). Muscle fiber analysis indicated that the increase in muscularity by the F94L allele in the semitendinosus and longissimus was likely due to hyperplasia as there was a 19% increase in the quantity of myosin heavy chain type IIA and IIX fibers in the semitendinosus (P < 0.05) with no effect on muscle fiber size (P > 0.05). Carcasses from steers with one F94L allele had larger ribeye areas (99.2 vs. 92.3 sq.cm.), greater ribeye width:length ratios (0.498 vs. 0.479), lower USDA yield grades (2.21 vs. 2.66), and lower marbling scores (438 vs. 480) (P < 0.05). Additionally, for boxed beef yields, one F94L allele, vs. zero F94L alleles, increased (P < 0.05) 85/15 trimmings (+0.59%), top round (+0.28%), strip loin (+0.12%), eye round (+0.11%), tenderloin (+0.07%), boneless foreshank (+0.07%), cap/wedge (+0.06%), and tri-tip (+0.04%). Overall, carcasses from steers with one F94L allele had a greater boxed beef yield (+1.06%), boxed beef plus 85/15 trimmings yield (+1.65%), and total retail cuts plus ground beef 85/15 yield (+1.78%) than carcasses from steers with zero F94L alleles (P < 0.05). One copy of the F94L allele utilized in beef-on-dairy breeding system had no significant impact on live performance traits but resulted in lower marbling scores and increased muscularity as evidenced through larger, more beef-shaped ribeyes, lower USDA yield grades, and greater carcass cutout yields (both boxed beef and retail yields).

In a beef-on-dairy system, one copy of the F94L myostatin allele caused increased muscling, resulting in larger, more beef-shaped ribeyes, more desirable yield grades, and greater boxed beef and retail yields, all of which address inherent deficiencies in dairy and dairy-cross carcasses. These improvements were realized with no negative effects on calving ease or live performance. The F94L did cause a significant and meaningful reduction in marbling score; therefore, marbling ability should be paramount in sire selection if F94L sires are utilized. Using a beef sire homozygous for F94L myostatin in a beef-on-dairy system would ensure that all resulting progenies have exactly one copy of the F94L allele, meaning that this genetic tool could be rapidly implemented in the beef-on-dairy industry segment. When selecting sires for beef-on-dairy programs, accurate EPDs should remain the primary evaluation tool as the F94L effects are reflected in accurate EPDs; however, using a sire homozygous for F94L (2 or 0 copies) should result in more consistent progeny.

Beef embryos in dairy cows: feedlot performance, mechanistic responses, and carcass characteristics of straightbred Holstein calves and Angus-sired calves from Holstein, Jersey, or crossbred beef dams.

Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. The objective of this sire-controlled study was to test the feedlot performance of straightbred beef calves raised on a calf ranch and to compare finishing growth performance, carcass characteristics, and mechanistic responses relative to beef × dairy crossbreds and straightbred beef cattle raised in a traditional beef cow/calf system. Tested treatment groups included straightbred beef steers and heifers reared on range (A × B; n = 14), straightbred beef steers and heifers born following embryo transfer to Holstein dams (H ET; n = 15) and Jersey dams (J ET; n = 16) The finishing trial began when cattle weighed 301 ±â€…32.0 kg and concluded after 195 ±â€…1.4 d. Individual intake was recorded from day 28 until shipment for slaughter. All cattle were weighed every 28 d; serum was collected from a subset of steers every 56 d. Cattle of straightbred beef genetics (A × B, H ET, and J ET) and A × H were similar in final shrunk body weight, dry matter intake, and carcass weight (P > 0.05 for each variable). Compared with A × J cattle, J ET was 42 d younger at slaughter with 42 kg more carcass weight (P < 0.05 for both variables). No difference was observed in longissimus muscle area between all treatments (P = 0.40). Fat thickness was greatest for straightbred beef cattle, least for A × J cattle, and intermediate for A × H cattle (P < 0.05). When adjusted for percentage of adjusted final body weight, feed efficiency was greater for straightbred beef cattle compared with beef × dairy crossbred cattle (P = 0.04). A treatment × day interaction was observed for circulating insulin-like growth factor I (IGF-I; P < 0.01); 112 d after being implanted, beef × dairy crossbred cattle had greater circulating IGF-I concentration than cattle of straightbred beef genetics (P < 0.05). Straightbred beef calves born to Jersey cows had more efficient feedlot and carcass performance than A × J crossbreds. Calves of straightbred beef genetics raised traditionally or in a calf ranch performed similarly in the feedlot.

Improved reproductive management has allowed dairy cow pregnancies to be optimized for beef production. The objectives of this study were to use an embryo transfer model 1) to investigate the effect of the dairy management system on beef genetics and 2) to directly compare the merit of Holstein and Jersey genetics for feedlot and carcass performance with modern beef genetics. Feedlot and carcass performance of straightbred beef cattle were similar regardless if the calf was raised in the traditional beef cow/calf system or if the calf was raised at a calf ranch. Based on greater daily live gain and carcass weight, Holstein maternal genetics had greater terminal merit than Jersey maternal genetics. Regardless of dam breed, dairy genetics increased carcass leanness. Minimal differences were detected between adjusted feed efficiency of beef and beef × dairy cattle, but underestimation of mature size of beef × dairy could have overestimated efficiency. Genetic differences were more impactful than differences between the conventional beef and dairy calfhood management systems on feedlot and carcass performance.

The effects of a nutritional packet (live yeast, vitamins C and B1, and electrolytes) offered to steers in a calf-fed system on growth performance, nutrient digestion, feeding behavior, carcass characteristics, and ruminal variables.

Effects of a nutritional packet strategically offered to calf-fed system steers on growth performance, nutrient digestibility, feeding behavior, ruminal variables, and carcass characteristics were evaluated. Angus crossbred steer-calves (N = 60; body weight [BW] = 234 ±â€…4 kg) were used in a randomized complete block design (block = BW) and stratified into two treatments: 1) control; and 2) 30 g/steer-daily (dry matter [DM] basis) of a nutritional packet containing (steer-daily basis): Live yeast (Saccharomyces cerevisiae; 1.7 × 1010 CFU), vitamin C (Ascorbic acid, 162 mg), vitamin B1 (thiamin hydrochloride, 400 mg), sodium chloride (2.4 g), and potassium chloride (2.4 g). Animals were offered (electronic feed-bunks [SmartFeed, C-Lock Inc., Rapid City, SD]), a steam-flaked corn-based finishing diet to ad libitum (individual intake), once daily for 233 d. Treatments were offered during the first and last 60 days on feed (DOF). The GLIMMIX procedure of SAS was used, with steer as the experimental unit, treatment and phase (for feeding behavior and digestibility) as fixed effects, and BW-block as a random effect. Steers offered the nutritional packet had 14% less (P < 0.01) intake and 18% greater (P = 0.01) feed efficiency during the initial 30 DOF. Intake (days 0 to 233) was 6% greater (P = 0.02) for steers offered the nutritional packet, while BW gain was not different (P ≥ 0.44). Greater (P = 0.02) dressing percent (61.1% vs. 62%) for steers offered the packet was observed, while other carcass variables were not different (P ≥ 0.33). Digestibility of DM, organic matter, and fiber were greater (P < 0.01) for steers offered the packet. Steers offered the packet spent 13% less time eating during the first 60 DOF, while during the last 60 DOF a 14% greater meal frequency and 12.3% smaller mean meal size (treatment × phase interaction, P < 0.02) were observed. Steers offered the packet had a reduced (P ≤ 0.01) mean meal duration during both phases. Regardless of treatment, a decreased rumination (P ≤ 0.03) and chewing (P ≤ 0.01) activities were observed for the last 60 DOF compared to the first 60 DOF. Ruminal papillae area was 30% greater (P = 0.02) and the total volatile fatty acid (VFA) tended (P = 0.09) to be greater for steers offered the nutritional packet. The nutritional packet offered to calf-fed steers improved feed efficiency during the initial 30 d after arrival, while inducing superior overall intake, nutrient digestibility, dressing percentage, ruminal papillae area, and total ruminal VFA.

Antibimicrobial Susceptibility of Trimethoprim-Sulfamethoxazole and 3rd-Generation Cephalosporin-Resistant Escherichia coli Isolates Enumerated Longitudinally from Feedlot Arrival to Harvest in High-Risk Beef Cattle Administered Common Metaphylactic Antimicrobials.

Multidrug resistant (MDR) Escherichia coli threaten the preservation of antimicrobials to treat infections in humans and livestock. Thus, it is important to understand where antimicrobial-resistant E. coli persist and factors that contribute to its their development. Crossbred cattle (n = 249; body weight = 244 kg ±25 kg standard deviation) were blocked by arrival date and assigned metaphylactic antimicrobial treatments of sterile saline control, tulathromycin (TUL), ceftiofur, or florfenicol at random. Trimethoprim-sulfamethoxazole (COTR) and third-generation cephalosporin (CTXR)-resistant E. coli were isolated from fecal samples on days 0, 28, 56, 112, 182, and study END (day 252 for block 1 and day 242 for block 2). Then, susceptibility testing was conducted on all confirmed isolates. MDR was detected in both COTR and CTXR E. coli isolates. In COTR isolates, the number of antimicrobials each isolate was resistant to and the minimum inhibitory concentration (MIC) for amoxicillin-clavulanic acid, ceftriaxone, and gentamicin was greatest on day 28 compared with all other days (p ≤ 0.04). Similarly, chloramphenicol MIC was greater on day 28 than on day 0 (p < 0.01). Overall, sulfisoxazole MIC was less for TUL than all other treatments (p ≤ 0.02), and trimethoprim-sulfamethoxazole MIC was greater for TUL than all other treatments (p ≤ 0.03). Finally, there was no effect of treatment, day, or treatment × day for tetracycline or meropenem MIC (p ≥ 0.07). In CTXR isolates, there was an effect of day for all antimicrobials tested except ampicillin and meropenem (p ≤ 0.06). In conclusion, administering a metaphylactic antimicrobial at feedlot arrival did influence the susceptibility of COTR and CTXR E. coli. However, MDR E. coli are widely distributed, and the MIC for most antimicrobials was not different from the initial value upon completion of the feeding period.

Descriptive Sensory Attributes and Volatile Flavor Compounds of Plant-Based Meat Alternatives and Ground Beef.

The objective of this study was to characterize descriptive sensory attributes and volatile compounds among ground beef (GB) and plant-based meat alternatives (PBMA). The Beyond Burger, Impossible Burger, a third brand of PBMA, regular GB, and lean GB were collected from local and national chain grocery stores. Patties were formed and cooked on an enamel-lined cast iron skillet to an internal temperature of 71 °C. A trained descriptive sensory panel evaluated patties for 17 flavor attributes and 4 texture attributes. Volatile compounds were extracted using solid phase microextraction and analyzed via gas chromatography-mass spectrometry. Distinct differences in sensory and volatile profiles were elucidated (p < 0.05). PBMA possessed decreased beef flavor intensity and increased umami, nutty, smokey-charcoal, and musty/earthy flavor compared to GB. Sensory differences corresponded with pyrazine, furan, ketone, alcohol, and aldehyde concentration differences between products. These data support the conclusion that ground beef and PBMA possess different flavor and texture characteristics. Furthermore, the flavor of PBMA varied among available retail brands.

Efficacy of Common Antimicrobial Interventions at and above Regulatory Allowable Pick-Up Levels on Pathogen Reduction.

The objective of this study was to evaluate the food safety efficacy of common antimicrobial interventions at and above required uptake levels for processing aids on the reduction of Shiga-toxin producing E. coli (STEC) and Salmonella spp. through spray and dip applications. Beef trim was inoculated with specific isolates of STEC or Salmonella strains. Trim was intervened with peracetic or lactic acid through spray or dip application. Meat rinses were serially diluted and plated following the drop dilution method; an enumerable range of 2-30 colonies was used to report results before log transformation. The combination of all treatments exhibits an average reduction rate of 0.16 LogCFU/g for STEC and Salmonella spp., suggesting that for every 1% increase in uptake there is an increase of 0.16 LogCFU/g of reduction rate. There is a statistical significance in the reduction rate of Shiga-toxin producing Escherichia coli in relation to the uptake percentage (p < 0.01). The addition of explanatory variables increases the R2 of the regression for STEC, where all the additional explanatory variables are statistically significant for reduction (p < 0.01). The addition of explanatory variables increases the R2 of the regression for Salmonella spp., but only trim type is statistically significant for reduction rate (p < 0.01). An increase in uptake percentages showed a significant increase in reduction rate of pathogens on beef trimmings.

The effects of a Nutritional Packet (live yeast, vitamins C and B1, and electrolytes) offered during the final phase of feedlot steers on growth performance, nutrient digestion, and feeding behavior.

The effects of a Nutritional Packet offered to beef steers during the final 64 d of the feedlot-finishing phase on growth performance, carcass characteristics, nutrient digestibility, and feeding behavior were evaluated. Angus-crossbred steers (N = 120; initial body weight = 544 ± 52 kg) were assigned to 30 pens (4 steers per pen; 15 pens per treatment) in a randomized complete block design where pen was the experimental unit. A steam-flaked corn-based finishing diet was offered to ad libitum, and the treatments were as follows: 1) control and 2) 30 g per steer-daily (dry matter basis) of the Nutritional Packet. The Nutritional Packet was formulated to provide 1.7 × 1010 CFU per steer-daily of Saccharomyces cerevisiae, 162 mg per steer-daily of vitamin C; 400 mg per steer-daily of vitamin B1; 2.4 g per steer-daily of NaCl, and 2.4 g per steer-daily of KCl. Data were analyzed using the GLIMMIX procedure of SAS with the fixed effect of treatment and the random effect of block. The average daily gain (P = 0.89), dry matter intake (P = 0.57), and gain efficiency (P = 0.82) were not affected by the inclusion of the Nutritional Packet. Digestibility of dry and organic matter, and neutral and acid detergent fiber increased (P ≤ 0.02) for steers offered the Nutritional Packet, while a trend for the same response was observed for hemicellulose (P = 0.08). The 12th rib backfat thickness increased (P = 0.02) for carcasses of steers offered the Nutritional Packet, followed by a greater (P = 0.03) calculated yield grade, whereas other carcass traits were not affected (P ≥ 0.32). While the steers under the control diet decreased behavior activities on day 63, a consistent pattern of feeding behavior measurements (activity min/d and min/kg of dry and organic matter, fiber fractions, and digestible nutrients) were observed for steers consuming the Nutritional Packet during both feeding behavior assessment periods (treatment × period interactions, P ≤ 0.03). Overall time (min/d) spent on rumination, drinking, active, chewing, and resting were not affected (P ≥ 0.28) by treatments. The Nutritional Packet offered to steers during the final 64 d on feed induced an improvement in apparent digestibility of nutrients and carcass fat deposition, without affecting growth performance or other carcass quality indices. Such effects associated with the more consistent feeding behavior of steers receiving the Nutritional Packet may warrant a shorter time on feed during the final portion of the finishing phase.

Excessive intake of rapidly fermentable nutrients by feedlot cattle can result in clinical or subclinical disorders that impair nutrient digestion, while negatively affecting animal development and health. Incidences of subclinical digestive disturbances may increase during the last days on feed in cattle fed in confinement. Manipulation of diets with probiotics (live yeast), vitamins (C and B1), and electrolytes (NaCl and KCl) to aid subclinical digestive disorders faced by cattle offered high-energy diets was addressed in the current experiment. The use of such nutritional technologies is based on previous reports that these technologies can stabilize ruminal pH, improve nutrient digestibility, enhance rumen microbial growth and energy metabolism, reduce oxidative stress, augment immune function, and prevent vitamin deficiencies induced by energy-dense diets. Therefore, it was important to investigate the effects of a packet containing these technologies during the feedlot final days on feed. When offered to steers during the final 64 d prior to harvest, a Nutritional Packet containing live yeast, vitamins C and B1, and electrolytes improved digestibility of nutrients and carcass fat deposition, while reducing variation in feeding behavior. Such effects may warrant an earlier harvest date when animals receive the packet.

Crossbreeding beef sires to dairy cows: cow, feedlot, and carcass performance.

Genetic and reproductive advancements in the dairy industry, volatile milk markets, and beef packer restrictions on dairy carcasses have increased the popularity of crossbreeding beef sires to dairy cows in the United States. This observational study aimed to understand performance of dairy cows bred to beef sires and feedlot and carcass performance of crossbred beef × dairy cattle. For dairy cow performance, archived records from two dairies representing two successive lactations were evaluated in cows (Dairy A: n = 72/group; Dairy B: n = 456/group) representing 1) All Dairy, where previous sire type of conception was Holstein for both lactations, or 2) Beef on Dairy, where previous sire type of conception was Holstein for the preceding lactation and a beef breed for the subsequent lactation. For feedlot performance, closeout data from pens (n = 26/cattle type) of beef and beef × dairy steers and heifers were evaluated. For carcass performance, individual carcass data were compared between conventional beef (n = 966), beef × dairy (n = 518), and Holstein (n = 935) steers sampled across a variety of processing facilities, harvest lots, and geographical regions. Cow lactation performance was minimally impacted by sire type of previous conception. Cows conceived to beef sires exhibited a 2 to 3 d greater (P < 0.01) gestation length than cows conceived to Holstein sires. Beef × dairy cattle were not largely different in weight gain at the feedlot but exhibited 1-unit lesser (P < 0.01) dressing percentage than beef cattle. Beef × dairy carcasses possessed 18% lesser (P < 0.05) 12th rib fat thickness than beef cattle and 5% greater (P< 0.05) ribeye area than dairy cattle. Additionally, beef cattle produced nearly double (P < 0.05) the percentage of yield grade 4 carcasses produced by beef × dairy and Holstein cattle.

Metaphylactic antimicrobial effects on occurrences of antimicrobial resistance in Salmonella enterica, Escherichia coli and Enterococcus spp. measured longitudinally from feedlot arrival to harvest in high-risk beef cattle.

AIMS: Our objective was to determine how injectable antimicrobials affected populations of Salmonella enterica, Escherichia coli and Enterococcus spp. in feedlot cattle. METHODS AND RESULTS: Two arrival date blocks of high-risk crossbred beef cattle (n = 249; mean BW = 244 kg) were randomly assigned one of four antimicrobial treatments administered on day 0: sterile saline control (CON), tulathromycin (TUL), ceftiofur (CEF) or florfenicol (FLR). Faecal samples were collected on days 0, 28, 56, 112, 182 and study end (day 252 for block 1 and day 242 for block 2). Hide swabs and subiliac lymph nodes were collected the day before and the day of harvest. Samples were cultured for antimicrobial-resistant Salmonella, Escherichia coli and Enterococcus spp. The effect of treatment varied by day across all targeted bacterial populations (p ≤ 0.01) except total E. coli. Total E. coli counts were greatest on days 112, 182 and study end (p ≤ 0.01). Tulathromycin resulted in greater counts and prevalence of Salmonella from faeces than CON at study end (p ≤ 0.01). Tulathromycin and CEF yielded greater Salmonella hide prevalence and greater counts of 128ERYR E. coli at study end than CON (p ≤ 0.01). No faecal Salmonella resistant to tetracyclines or third-generation cephalosporins were detected. Ceftiofur was associated with greater counts of 8ERYR Enterococcus spp. at study end (p ≤ 0.03). By the day before harvest, antimicrobial use did not increase prevalence or counts for all other bacterial populations compared with CON (p ≥ 0.13). CONCLUSIONS: Antimicrobial resistance (AMR) in feedlot cattle is not caused solely by using a metaphylactic antimicrobial on arrival, but more likely a multitude of environmental and management factors.

Invited review: a carcass and meat perspective of crossbred beef × dairy cattle.

Crossbreeding dairy cows with beef sires has greatly altered the consist of U.S. dairy-influenced slaughter cattle and generated an influx of crossbred beef × dairy cattle to the U.S. fed beef slaughter supply in 2021. This review provides a summary of our observations of carcass and meat traits in the recent U.S. beef × dairy crossbred population and, based on these observations, exposes future opportunities for consideration. Strip loin steaks from beef × dairy cattle can be marketed alongside conventional beef products in retail display without consumer discrimination based on color or steak shape previously experienced in steaks from straightbred dairy cattle. Additionally, beef from crossbred beef × dairy cattle cannot be discriminated against for eating quality attributes (tenderness, flavor, and juiciness) as it exhibits similar, if not improved, performance of these attributes to beef from conventional beef cattle. We have also demonstrated that live expression of beef-type versus dairy-type character within the beef × dairy crossbred population has minimal effect on eating quality. With proper genetic selection and management, crossbred beef × dairy cattle can capture carcass premiums from an optimal combination of carcass quality (marbling) and red meat yield. Future beef × dairy crossbred mating and management systems should emphasize increases in total carcass muscling and reductions in liver abscess prevalence. A story of quality, sustainability, and traceability in the large and constant supply of beef from crossbred beef × dairy cattle may present profitable branding and marketing opportunities for these products.

Effects of physical activity and feed and water restriction at reimplanting time on feed intake patterns, growth performance, and carcass characteristics of finishing beef steers.

In the feedlot, there can be a decrease in dry matter intake (DMI) associated with reimplanting cattle that negatively affects growth performance. This study was conducted to determine the mechanisms causing a decrease in DMI after reimplanting and identify a strategy to mitigate the decrease. Crossbred steers (n = 200; 10 pens/treatment; initial bodyweight [BW] = 386 ±â€…4.9 kg) were used in a randomized complete block design experiment. Cattle were implanted with Revalor-IS on day 0. Treatments included a Revalor-200 implant on day 90 before feeding with the following management practices imposed: 1) steers were returned to their home pen immediately after reimplant (PCON); 2) steers were placed in pens and restricted from feed and water for 4 h (RES); 3) steers were walked an additional 805 m after reimplant and then returned home (LOC); 4) steers were restricted from feed and water for 4 h and walked an additional 805 m (RES + LOC); 5) steers were given an oral bolus of Megasphaera elsdenii (Lactipro; MS Biotec, Wamego, KS) and were restricted from feed and water for 4 h, and then walked an additional 805 m (LACT). One hundred steers were given an ear tag to record minutes of activity (ESense Flex Tags, Allflex Livestock Intelligence, Madison, WI). As a percentage of BW, DMI was 5% greater (P = 0.01) from reimplant to end for PCON vs. RES, LOC, and RES + LOC treatments. Likewise, as a percentage of BW, DMI was 6.6% greater (P = 0.03) from reimplant to end and 4.0% greater (P = 0.05) overall for the PCON treatment vs. the LOC treatment. Overall, DMI as a percentage of BW was 3.3% greater (P = 0.02) for PCON vs. RES, LOC, and RES + LOC treatments. There was an increase in G:F from reimplant to end (P = 0.05) for RES + LOC vs. the LACT treatment. From these data, we conclude that restricting cattle from feed and water for 4 h after reimplanting did not alter subsequent DMI. Increasing locomotion had the greatest negative effect on DMI and growth performance. Management strategies to decrease locomotion associated with reimplanting would be beneficial to DMI and overall growth performance of finishing beef steers.

Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on feedlot beef cattle production.

Two experiments were performed to evaluate the effects of bismuth subsalicylate (BSS) and calcium-ammonium nitrate (CAN) on in vitro ruminal fermentation, growth, apparent total tract digestibility of nutrients, liver mineral concentration, and carcass quality of beef cattle. In Exp. 1, four ruminally cannulated steers (520 ± 30 kg body weight [BW]) were used as donors to perform a batch culture and an in vitro organic matter digestibility (IVOMD) procedure. Treatments were arranged in a 2 × 2 factorial with factors being BSS (0 or 0.33% of substrate dry matter [DM]) and CAN (0 or 2.22% of substrate DM). In Exp. 2, 200 Angus-crossbred steers (385 ± 27 kg BW) were blocked by BW and allocated to 50 pens (4 steers/pen) in a randomized complete block design with a 2 × 2 + 1 factorial arrangement of treatments. Factors included BSS (0 or 0.33% of the diet DM) and nonprotein nitrogen (NPN) source (urea or encapsulated CAN [eCAN] included at 0.68% or 2.0% of the diet, respectively) with 0.28% ruminally available S (RAS). A low S diet was included as a positive control containing urea (0.68% of DM) and 0.14% RAS. For Exp. 1, data were analyzed using the MIXED procedure of SAS with the fixed effects of BSS, CAN, BSS × CAN, and the random effect of donor. For Exp. 2, the MIXED procedure of SAS was used for continuous variables and the GLIMMIX procedure for categorical data. For Exp. 1, no differences (P > 0.230) were observed for IVOMD. There was a tendency (P = 0.055) for an interaction regarding H2S production. Acetate:propionate increased (P = 0.003) with the addition of CAN. In Exp. 2, there was a NPN source effect (P = 0.032) where steers consuming urea had greater carcass-adjusted final shrunk BW than those consuming eCAN. Intake of DM (P < 0.001) and carcass-adjusted average daily gain (P = 0.024) were reduced by eCAN; however, it did not affect (P = 0.650) carcass-adjusted feed efficiency. Steers consuming urea had greater (P = 0.032) hot carcass weight, and a BSS × NPN interaction (P = 0.019) was observed on calculated yield grade. Apparent absorption of S decreased (P < 0.001) with the addition of BSS. Final liver Cu concentration was reduced (P = 0.042) by 58% in cattle fed BSS, indicating that BSS may decrease Cu absorption and storage in the liver. The results observed in this experiment indicate that BSS does not have negative effects on feedlot steer performance, whereas CAN may hinder performance of steers fed finishing diets.

Microbial Growth Study on Pork Loins as Influenced by the Application of Different Antimicrobials.

The use of antimicrobials in the pork industry is critical in order to ensure food safety and, at the same time, extend shelf life. The objective of the study was to determine the impact of antimicrobials on indicator bacteria on pork loins under long, dark, refrigerated storage conditions. Fresh boneless pork loins (n = 36) were split in five sections and treated with antimicrobials: Water (WAT), Bovibrom 225 ppm (BB225), Bovibrom 500 ppm (BB500), Fit Fresh 3 ppm (FF3), or Washing Solution 750 ppm (WS750). Sections were stored for 1, 14, 28, and 42 days at 2-4 °C. Mesophilic and psychrotrophic aerobic bacteria (APC-M, APC-P), lactic acid bacteria (LAB-M), coliforms, and Escherichia coli were enumerated before intervention, after intervention, and at each storage time. All bacterial enumeration data were converted into log10 for statistical analysis, and the Kruskal-Wallis test was used to find statistical differences (p < 0.05). Initial counts did not differ between treatments, while, after treatment interventions, treatment WS750 did not effectively reduce counts for APC-M, APC-P, and coliforms (p < 0.01). BB500, FF3, and WS750 performed better at inhibiting the growth of indicator bacteria when compared with water until 14 days of dark storage.