Creatine stores high-energy phosphate bonds in muscle and is synthesized in the liver through methylation of guanidinoacetic acid (GAA). Supplementation of GAA may therefore increase methyl group requirements, and this may affect methyl group utilization. Our experiment evaluated the metabolic responses of growing cattle to postruminal supplementation of GAA, in a model where methionine (Met) was deficient, with and without Met supplementation. Seven ruminally cannulated Holstein steers (161 kg initial body weight [BW]) were limit-fed a soybean hull-based diet (2.7 kg/d dry matter) and received continuous abomasal infusions of an essential amino acid (AA) mixture devoid of Met to ensure that no AA besides Met limited animal performance. To provide energy without increasing the microbial protein supply, all steers received ruminal infusions of 200 g/d acetic acid, 200 g/d propionic acid, and 50 g/d butyric acid, as well as abomasal infusions of 300 g/d glucose. Treatments, provided abomasally, were arranged as a 2 × 3 factorial in a split-plot design, and included 0 or 6 g/d of l-Met and 0, 7.5, and 15 g/d of GAA. The experiment included six 10-d periods. Whole body Met flux was measured using continuous jugular infusion of 1-13C-l-Met and methyl-2H3-l-Met. Nitrogen retention was elevated by Met supplementation (P < 0.01). Supplementation with GAA tended to increase N retention when it was supplemented along with Met, but not when it was supplemented without Met. Supplementing GAA linearly increased plasma concentrations of GAA and creatine (P < 0.001), but treatments did not affect urinary excretion of GAA, creatine, or creatinine. Supplementation with Met decreased plasma homocysteine (P < 0.01). Supplementation of GAA tended (P = 0.10) to increase plasma homocysteine when no Met was supplemented, but not when 6 g/d Met was provided. Protein synthesis and protein degradation were both increased by GAA supplementation when no Met was supplemented, but decreased by GAA supplementation when 6 g/d Met were provided. Loss of Met through transsulfuration was increased by Met supplementation, whereas synthesis of Met from remethylation of homocysteine was decreased by Met supplementation. No differences in transmethylation, transsulfuration, or remethylation reactions were observed in response to GAA supplementation. The administration of GAA, when methyl groups are not limiting, has the potential to improve lean tissue deposition and cattle growth.

Creatine stores energy in muscles as high-energy phosphate bonds. Creatine is endogenously synthesized in the liver through the methylation of guanidinoacetic acid. We hypothesized that provision of guanidinoacetic acid, the precursor to creatine, would increase creatine supply to the body and improve animal production. Because increased synthesis of creatine will increase methyl group consumption, an adequate supply of methyl groups might improve the benefits of guanidinoacetic acid supplementation. This study was to determine whether guanidinoacetic acid supplementation could improve lean tissue deposition (growth) and whether an additional methyl group source (methionine) was required to optimize the response to guanidinoacetic acid. Ruminally-cannulated steers were housed in metabolism crates to allow complete collection of feces and urine for calculation of nitrogen retention. The experiment included six 10-day periods, and each animal received one of the 6 different treatments in each period. The 6 treatments were supplementation of 0, 7.5, or 15 g/day of guanidi-noacetic acid each in the presence or absence of 6 g/day supplemental L-methionine. Supplementation of guanidinoacetic acid increased plasma creatine concentrations, demonstrating that the cattle converted guanidinoacetic acid to creatine. Responses to guanidinoacetic acid for lean tissue deposition were dependent on the methionine status of the steers. When methionine was supplemented to steers, there was an increase in nitrogen retention when 15 g/day of guanidinoacetic acid was provided. In contrast,

Heat stress in feedlot cattle has serious animal welfare and economic implications. The objective of this experiment was to determine whether a titanium dioxide coating applied to the dorsal midline of cattle would reflect solar radiation and mitigate heat stress. Feedlot heifers (n = 30; 269 ± 27.6 kg) were randomly assigned to a noncoated (control) or titanium dioxide–coated treatment. Coating was applied to the dorsal midline except for a control area over the dorsal anterior midline. Reflectance was measured with a suspended modified digital camera in a blue band, a green band, and a near-infrared band. Skin surface temperature was measured with a suspended infrared thermal imaging sensor. Vaginal thermometers recorded the internal body temperature of heifers. Reflectance in the blue, green, and red edge to near infrared bands were found to be 5.7, 8.8, and 10.3 times greater (P < 0.001), respectively, for the coated areas compared with the noncoated areas. Dorsal surface temperature averaged 39.1 and 42.4°C for coated and noncoated areas, respectively (P < 0.001). Reflectance values and skin surface temperatures suggest that the coating decreased solar energy absorption. Over a 2- to 3-h period of exposure to natural solar radiation on a day with temperature–humidity index of 86.9, titanium dioxide–coated cattle had stable body temperatures, whereas the body temperatures of control heifers increased 0.8°C. A reflective coating applied to the dorsal midline could be an opportunity to decrease solar radiation energy absorbed by feedlot cattle.

The objective of this study was to determine the effects of liver abscess severity in beef cattle at slaughter on meat tenderness and sensory attributes of steaks from USDA Low Choice and Select quality grades. Liver abscesses at the time of slaughter have been shown to decrease hot carcass weight, dressing percentage, yield grade, and marbling scores. However, little research has focused on the effects of animal health and disease parameters, including liver abscesses, on meat tenderness and sensory attributes.

Abstract Cattle mobility is routinely measured at commercial slaughter facilities. However, the clinical signs and underlying causes of impaired mobility of cattle presented to slaughter facilities are poorly defined. As such, the objectives of this study were 1) to determine the prevalence of impaired mobility in finished cattle using a 4-point mobility scoring system and 2) to observe clinical signs in order to provide clinical diagnoses for this subset of affected cattle. Finished beef cattle (n = 65,600) were observed by a veterinarian during the morning shift from six commercial abattoirs dispersed across the United States; the veterinarian assigned mobility scores (MS) to all animals using a 1–4 scale from the North American Meat Institute’s Mobility Scoring System, with 1 = normal mobility and 4 = extremely limited mobility. Prevalence of MS 1, 2, 3, and 4 was 97.02%, 2.69%, 0.27%, and 0.01%, respectively. Animals with an abnormal MS (MS > 1) were then assigned to one of five clinical observation categories: 1) lameness, 2) poor conformation, 3) laminitis, 4) Fatigued Cattle Syndrome (FCS), and 5) general stiffness. Of all cattle observed, 0.23% were categorized as lame, 0.20% as having poor conformation, 0.72% as displaying signs of laminitis, 0.14% as FCS, and 1.68% as showing general stiffness. The prevalence of lameness and general stiffness was greater in steers than heifers, whereas the prevalence of laminitis was the opposite (P < 0.05). FCS prevalence was higher in dairy cattle than in beef cattle (0.31% vs. 0.22%, respectively; P ≤ 0.05). These data indicate the prevalence of cattle displaying abnormal mobility at slaughter is low and causes of abnormal mobility are multifactorial.

Feedlot cattle ( = 128; BW = 549 ± 60 kg) were used to evaluate the effects of ractopamine hydrochloride (RAC) on growth performance, physiological response to handling, and mobility during shipment for slaughter in a study utilizing a split-plot design with a 2 × 2 factorial arrangement of treatments: 1) diet (CON [no β-adrenergic agonist] vs. RAC [400 mg·animal·d ractopamine hydrochloride for 28 d]) and 2) handling intensity (HI; low-stress handling [LSH; cattle moved at a walking pace with no electric prod use] vs. high-stress handling [HSH; cattle moved at a minimum of a trot and an electric prod applied while in the alley for posthandling restraint and during loading for shipment to the abattoir]). Cattle fed RAC tended to have greater ADG and G:F ( = 0.06), and had greater HCW and LM area ( = 0.04). The HI treatments were applied on the day after the 28-d growth performance period. Blood samples were collected before HI treatment (baseline), after HI treatments (POSTHAND), after transport to the abattoir (POSTTRANS), and during exsanguination at slaughter. A diet × HI interaction ( = 0.01) was observed in the change in cortisol from baseline to POSTTRANS, and there tended ( ≤ 0.07) to be diet × HI interactions for the change in epinephrine from baseline to POSTHAND and for the change in creatine kinase (CK) from baseline to POSTTRANS. Feeding RAC and HSH both increased the change from baseline to POSTHAND in norepinephrine and pH ( ≤ 0.05). The HSH cattle also had greater changes from baseline to POSTHAND in blood HCO, base excess, partial pressure of CO, lactate, cortisol, and glucose ( ≤ 0.01). Ractopamine and HSH both produced greater increases in CK concentrations from baseline to slaughter ( < 0.01). Mobility was not affected by RAC at the feedlot or following an average 6-h lairage ( ≥ 0.43). This study confirms RAC improves growth performance and suggests metabolic acidosis, a precursor to fatigued cattle syndrome, develops in cattle allowed to trot without the use of a lead rider regardless of RAC administration. Cattle fed RAC displayed altered hormonal responses to handling and transport stress, and the overall proportion of cattle with compromised mobility appears to increase later in the marketing channel. These findings warrant additional research aimed at better understanding the physiological response to stress and protect the welfare of cattle during shipment for slaughter.

Abstract Cattle injuries can occur during transportation due to vehicle design, transport conditions, and loading or unloading procedures and lead to carcass bruising and economic loss due to decreased carcass value. The objectives of this study were to determine whether a relationship exists between trauma incurred during unloading and prevalence of carcass bruising in finished beef cattle at commercial slaughter facilities and determine related risk factors which contribute to both trauma and carcass bruising. Breed (classified as either Holstein cattle or beef breeds), sex, distance traveled, and trailer type (“fat/feeder combination” vs. “fat” trailer) were considered risk factors which may contribute to traumatic event prevalence. When carcass bruise prevalence within each lot was used as the dependent variable, breed, sex, distance traveled, traumatic event prevalence, ribeye area, fat thickness, yield grade, and average carcass weight were considered potential risk factors. Carcass bruises were categorized by location and size, according to the Harvest Audit Program Carcass Bruise Scoring System. Traumatic events were observed while cattle exited trailers onto the unloading docks, and were categorized by location on the animal. Average traumatic event prevalence per lot was 20.4% (± 1.11%). Average carcass bruise prevalence by lot was 68.2% (± 1.15%). There was an interaction between breed and trailer type when multiple linear regression was used to explore variables contributing to traumatic events observed at unloading (P ≤ 0.05). Traumatic events were not associated with prevalence of carcass bruising, while average carcass weight and breed were associated with carcass bruising prevalence. Carcass bruising was more prevalent in Holstein cattle than in cattle which were predominantly beef breeds (P ≤ 0.01). Average carcass weight was negatively associated with carcass bruise prevalence (P ≤ 0.05). The association between traumatic events at unloading and carcass bruising is not significant when multiple variables are considered, indicating that bruising may occur at numerous other points prior to and during the transportation process, including loading and transport, and that other variables can contribute to carcass bruise prevalence. These areas should be explored to determine all potential causes of bruising in beef carcasses, and to help implement prevention practices.

Introduction: Atrial. premature complexes have been reported to be the Electrocardiography; most common arrhythmia in cattle and is suspected to be secondary to systemic dis ease, especially gastrointestinal disease. In order to properly identify pathologic arrhythmia in cattle, the normal rhythm and arrhythmia prevalence should be defined. The objective of this study was to determine the normal heart rate, rhythm, number of ventricular premature complexes (VPCs), and atrial premature complexes (APCs) in unrestrained Angus steers.Animals: Twenty-seven client owned steers with unremarkable physical examinations and serum biochemical analyses were used.Materials and methods: Twenty-four hour Hotter monitors, attached by a custommade harness, were retrospectively evaluated. Three lead electrocardiographic registrations of good quality and normal sinus rhythm were obtained from all steers in the study.Results: The mean heart rate was 66.8 bpm +/- 16.4 bpm. Ventricular premature complexes were rare (noted in 14.8% of steers), and APCs were common (noted in 85% of the steers). Simple second degree AV block was observed in 18.5% of the steers.Conclusion: In summary, healthy steers have rare single VPCs, although it is possible for an individual animal to have apparent more frequent VPCs. Mean heart rate varies with a diurnal pattern similar to other species. Atrial premature complexes are the most prevalent abnormality observed in feedlot steers. (C) 2016 Elsevier B.V. All rights reserved.

Facilities used by the feedlot industry have diverse designs, and published data describing these designs are not found in the literature. Feedlot managers (n = 43) responded to a survey describing general feedlot information, shipping and receiving areas, finishing pens, and hospital facilities currently used in the High Plains region of the United States (TX, OK, NM, CO, KS, NE). Feedlots reported one-time capacities of <10,000 animals (21%); 10,000 to 20,000 animals (26%); and >20,000 animals (53%). Cattle processing facility design and equipment used consisted primarily of crowding tubs (74%) and Bud Boxes (19%). Most feedlots (95%) reported 9.3 m2/animal of pen space for receiving cattle, 68% of feedlots provided 13.9 to 18.6 m2/animal of pen space for calves with elevated risk of respiratory disease, and 66% of feedlots provided 9.4 to 23.2 m2/animal of pen space for finishing cattle. Bunk space of 22.9 to 30.5 cm/animal for calves at elevated risk of respiratory disease and bunk space of 22.6 to 30.5 cm/animal for finishing cattle were provided by 55% of feedlots. Linear water tank space of 7.6 to 15.2 cm/animal for finishing cattle was allowed by 27% of feedlots. Windbreaks (43%) and mounds (71%) were used in finishing pens of feedlots surveyed. Few feedlots (17%) provided shade in feeding pens, although 50% provided shade in hospital pens. Dedicated health treatment facilities that were distinct from the postarrival processing facility were reported in 66% of feedlots surveyed. These data benchmark characteristics of outdoor cattle feeding facilities in the High Plains region of the United States.

Yearling Red Angus or Black Angus bulls (n = 24; initial BW = 1,336 ± 25.1 lb; (606 ± 11.4 kg); average 16 mo of age) were used to evaluate the effects of castration and use of growth promoting technology (STR) on performance, carcass traits, and meat quality characteristics when compared to intact (BULL) post-pubertal male cattle. The STR treatment included administration of a combination 120 mg trenbolone acetate + 24 mg estradiol growth-promoting implant on d 0 and feeding ractopamine hydrochloride the last 28 d on feed. Cattle were individually fed a corn-based finishing diet for 62 d and harvested at a commercial abattoir. Intact bulls had greater average daily gain ( 4.08 vs 3.19 lb or 1.85 vs 1.45 kg/d; P = 0.02) and feed:gain ratio (8.54 vs 10.97; P = 0.02) than STR. There were no treatment differences for dry-matter intake, quality or yield grade, hot carcass weight, back-fat thickness, or dressing percent (P < 0.05). Longissimus muscle area was greater in BULL compared to STR carcasses (16.6 vs 15.0 in2 or 106.9 vs 96.8 cm2; P < 0.01). Warner-Bratzler Shear Force was not affected (P > 0.05) by treatment. Intact bulls had improved performance with no differences in carcass characteristics, tenderness, or sensory panel measurements compared to STR treatment.

Carcass bruising of finished cattle can be attributed to suboptimal cattle handling and has become an animal welfare concern. Bruised carcasses require excess trimming, leading to increased sanitation risk and loss in time, and can potentially decrease profits. The objective of this study was to evaluate the relationship between the prevalence of horns and prevalence of bruising in lots of cattle at a commercial slaughter facility and to report size of horns and the anatomical location and severity of bruising on beef carcasses. Carcasses (n = 4,287) of feedlot cattle were observed at one commercial beef packing plant in southwest Kansas. Within lots of cattle, the percentage of cattle with horns averaged 7.7 ± 7.4% and ranged from 1.3 to 26.4%. Average single horn length was 11.1 cm and average distance from horn tip to horn tip was 39.6 cm. Of the carcasses evaluated, 55.2 ± 23.2% had one or more bruises and 25.6 ± 8.3% were severe (>15 cm), 35.6 ± 7.0% were moderate (5 to 15 cm), and 38.8 ± 12.5% were minor (<5 cm). The majority of bruises (61.8%) occurred on the dorsal midline, with 18.6% on the left side and 19.5% on the right side. The prevalence of bruising on the caudal third was 21.8%, on the center was 60.5%, and on the anterior region was 17.6% of the entire carcass. Results from these data suggest there was no significant relationship between the prevalence of horns and the prevalence of bruises in a lot of cattle, indicating that further research evaluating causation of carcass bruising is needed.

Cross-bred heifer calves (n = 579; initial bodyweight 404 ± 27.4 lb; 183.3 ± 12.4 kg) were utilized in a randomized, complete block design to compare 3 different antibiotics for control of bovine respiratory disease (BRD) in light-weight feeder heifers. Cattle originated from southeast Texas and were shipped approximately 700miles(1125 km) to the Clayton (New Mexico) Livestock Research Center. Heifers were randomly allocated off the truck into 30 pens, and administered 1 of 3 metaphylactic treatments at initial processing: 1) tulathromycin (TUL; 1.13 mg/lb (2.5 mg/kg)); 2) tilmicosin (TIL; 6 mg/lb (13.3 mg/kg)); or 3) gamithromycin (GAM; 2.72 mg/lb (6.0 mg/kg)). Heifers administered TUL had 0.29 lb (0.13 kg) greater (95% Cl = 2.27 to 2.46) average daily gain than cattle administered GAM. Cattle administered TUL had a lower (5.2%; 95% Cl = 1.2 to 9.1) morbidity rate than calves in the TIL (14.6%; 95% Cl = 6.7 to 22.5) and GAM (12.79%; 95% Cl = 7.7 to 17.9) groups. There were no differences in DM I or mortality in cattle between treatments.

OBJECTIVETo describe the incidence of specific causes of lameness and the associations of cause and severity of lameness on the outcome for cattle on commercial feedlots.DESIGNDynamic population longitudinal study.ANIMALSCattle on 6 commercial feedlots in Kansas and Nebraska during a 12-month period (mean daily population, 243,602 cattle; range, 223,544 to 252,825 cattle).PROCEDURESFeedlot personnel were trained to use a standardized diagnostic algorithm and locomotion score (LMS) system to identify and classify cattle by cause and severity of lameness. Information regarding lameness cause, severity, and treatments was recorded for individual cattle. Cattle were monitored until they left the feedlot (ie, outcome; shipped with pen mates [shipped], culled prematurely because of lameness [realized], or euthanized or died [died]). Incidence rates for various causes of lameness, LMSs, and outcomes were calculated. The respective associations of cause of lameness and LMS with outcome were evaluated.RESULTSLameness was identified in 2,532 cattle, resulting in an overall lameness incidence rate of 1.04 cases/100 animal-years. Realized and mortality rates were 0.096 cattle/100 animal-years and 0.397 deaths/100 animal-years, respectively. Injury to the proximal portion of a limb was the most frequently identified cause of lameness followed by undefined lameness, septic joint or deep digital sepsis, and interdigital phlegmon (foot rot). As the LMS (lameness severity) at lameness detection increased, the percentage of cattle that died but not the percentage of cattle that were realized increased.CONCLUSIONS AND CLINICAL RELEVANCEResults provided clinically useful prognostic guidelines for management of lame feedlot cattle.

Steam-flaked corn is commonly fed in feedlot finishing diets because steam-flaking improves starch availability and nutrient utilization, thus improving the overall feeding value of corn. In most operations which utilize steam-flaked corn, grain is processed to a pre-determined flake density by setting the rolls to a specific separation distance and using tension to hold rolls together. Flaked grain is most often produced to a bulk density between 24 and 32 lb/bu, with a common recommendation of 27 lb/bu for corn; however, flake density among steam-flakers within a single mill and among feedlots can vary greatly. Flaking to a similar density using 2 flakers does not ensure similar starch availability.

Antibiotic use in the beef industry is of increasing interest to consumers and has become a point of discussion for producers, veterinarians, and professional scientists in recent years. With the vast amount of information available on the internet and social media, consumers are becoming more knowledgeable about beef production practices and the use of antibiotics in the food animal industries. Furthermore, scientists have devoted a large amount of time and money to research to investigate consumer opinions and perspectives about management practices used in food animal production. However, many of these investigations fail to include the opinions and perspectives of the producers who raise these animals. Therefore, the objective of this survey was to explore producer practices and opinions on antibiotic use and antibiotic resistance in the beef industry.

Dry-rolling corn is a common practice in feedlots located in the Midwestern and Northern Plains regions of the United States. Optimizing total digestive tract starch utilization in diets containing dry-rolled corn is essential for maximizing efficiency. However, recommendations often suggest that grain be coarsely cracked to avoid producing an excessive amount of fine material that could potentially increase the rate of fermentation, reduce rumen pH, and cause digestive disturbances.

Two separate sets of 6 ruminally cannulated Holstein steers (240 kg) were used to study effects of ractopamine on lysine utilization. Steers were housed in metabolism crates and limit-fed 2.52 kg DM/d of a diet (10.1% CP) containing 82% soybean hulls twice daily. Treatments were arranged as a 2 × 3 factorial with 2 levels of ractopamine-HCl (0 and 200 mg/d) and 3 levels of lysine (0, 6, and 15 g/d) continuously infused abomasally. For each replicate of 6 steers, a completely randomized design was used for main-plot treatments (ractopamine-HCl; 0 vs 200 mg/d). Each steer received subplot treatments (lysine; 0, 6, or 15 g/d) in random sequence, such that each replicate contained concurrent 3 × 3 Latin squares, with each Latin square representing either 0 or 200 mg/d ractopamine-HCl. All steers were continuously infused ruminally with 200 g/d acetic acid, 200 g/d propionic acid, and 50 g/d butyric acid and abomasally with 300 g/d glucose to increase energy supply. Urea (10 g/d) was infused ruminally to ensure adequate ruminal ammonia. Steers were abomasally infused with excess of all essential AA except lysine to ensure lysine was solely limiting. Periods were 6 d with N retention measured on d 3 to 6 and longissimus biopsies and blood collected on d 6. Lysine increased (P<0.01) N retention for both control steers (21.3, 28.6, 33.9 g/d) and ractopamine-fed steers (25.5, 33.2, 38.9 g/d); ractopamine tended (P= 0.07) to increase N retention. Lysine linearly decreased (P<0.01) plasma urea (2.83, 2.04, 1.88 mM), leucine, and valine, but increased (P<0.01) plasma lysine (34, 51, 76 mM), arginine, and alanine. Ractopamine decreased (P<0.05) plasma lysine and arginine concentrations. In longissimus, ractopamine increased (P<0.05) phosphorylation of RPS6 on Ser-235 and Ser-244, and tended to increase (P= 0.08) phosphorylation of AKT on Thr-308 but not Ser-473. Abundance of MAFbx was decreased (P= 0.01) and MURF1 was numerically decreased (P= 0.14) by ractopamine. Lysine supplementation did not affect phosphorylation of RPS6 or AKT or abundance of MAFbx or MURF1. The efficiency of lysine use between 0 and 6 g/d supplemental lysine was 49% for control and 51% for ractopamine-supplemented steers. N retention tended to be improved by ractopamine when lysine supply was limiting, but incremental efficiencies of lysine utilization were not affected by ractopamine, suggesting that ractopamine reduced maintenance requirements for lysine.

Liver abscesses are a significant problem in the United States’ cattle feeding industry, costing the industry an estimated $15.9 million annually in liver condemnation, trim losses, and reduced carcass weights and quality grades. Recent reported incidence rates of liver abscesses at slaughter range from 10 to 20%. Liver abscess incidence may be influenced by a number of factors including: breed, gender, diet, days on feed, cattle type, season, and geographical location. Liver abscesses typically occur secondary to rumen insults caused by acidosis or rumenitis. It has been proposed that pathogens associated with liver abscess formation enter the blood stream through damaged rumen epithelium and are transported to the liver through the portal vein where they cause infection, manifested as liver abscesses. Severe liver abscesses have been linked to reduction in hot carcass weight, dressing percentage, yield grade, longissimus muscle area, and marbling scores of carcasses when compared to those with normal livers. However, the effect of liver abscesses on meat tenderness and sensory attributes has not been previously investigated.

Strip loin steaks (n = 119) were used to evaluate the association between liver abscess severity and USDA quality grade and meat tenderness and sensory attributes of steaks from finished feedlot cattle. Steaks were used in a 3 × 2 factorial treatment structure using a completely randomized design and were collected at a commercial abattoir located in northwest Texas. All cattle were sourced from a single feedlot and fed a common diet that did not include tylosin phosphate. Treatments were USDA quality grades of Select (SEL) and Low Choice (LC) and liver abscess scores of normal (NORM; healthy liver, no abscesses), mild (M; 1 abscess less than 2 cm in diameter to 4 abscesses less than 4 cm in diameter), and severe (SV; 1 abscess greater than 4 cm in diameter or greater than 4 small abscesses). All steak samples were collected on the same day, approximately 36-h post-mortem and were cut from the left side of the carcass at the 13th rib by a trained abattoir employee. Steaks were vacuum-packaged, and aged at 3 ± 1°C for 14-d post-mortem. Warner-Bratzler Shear Force (WBSF) and Slice Shear Force (SSF) analyses were conducted and cook-loss percentage was measured. A trained sensory panel analyzed samples for juiciness, tenderness, and flavor attributes. There were no differences among liver abscess scores for WBSF or SSF (P > 0.52). Warner-Bratzler Shear Force was lower for LC-SV than SEL-SV (P = 0.04). Sensory attributes of initial and sustained juiciness, and overall tenderness were all greater for LC than for SEL steaks (P < 0.04) and connective tissue amount was less for LC steaks when compared to SEL (P = 0.03). Liver abscess score had no effect on any sensory attributes (P > 0.70); however, there was an interaction between quality grade and liver score for myofibillar tenderness (P = 0.03). Within LC steaks, liver abscess score had no effect on myofibrillar tenderness (P > 0.05), however, in SEL steaks, M steaks were more tender than SV steaks (P < 0.03). These results indicate that within quality grades, meat tenderness or sensory attributes were not influenced by liver abscess score but that mild liver abscesses may affect the myofibrillar tenderness of SEL steaks.

Bull breeding soundness evaluations are often performed as a critical component of beef cow herd management to ensure that herd bulls have adequate semen quality, are physically capable of enduring the breeding season, and to determine the serving capacity per bull. Currently, there are approximately 30.3 million beef cows and 2.1 million bulls in the U.S. Depending on the breeding soundness evaluation failure rate, there are likely several hundred thousand bulls which will enter the beef market annually and a portion will be young bulls with the potential to be fed and sold to produce saleable meat of choice or select quality grade.