The objective of the study was to determine the effect of extended aging on the flavor development of various muscles, individually stored in vacuum rollstock packaging. Strip loins, paired tenderloins, and top sirloin butts (n=48) from USDA Low Choice carcasses (Small00 to Small100 marbling score, n=16). Subprimals were wet-aged in the absence of light for 28 d postmortem before fabrication into 2.54 cm steaks representing the longissimus lumborum (LL), psoas major (PM), and gluteus medius (GM). Steaks were individually packaged in vacuum rollstock packaging and assigned to an additional aging time of 28, 35, 42, 49, or 56 d. Cut steaks (n=240/test) were designated to trained descriptive panel analysis or volatile compound analysis. No interactions occurred for trained sensory analysis, but a main effect of days of age (P≤0.033) showed the greatest effect on negatively associated attributes, including liver-like, oxidized, fishy, bitter, and sour, after 42 d of aging. A main effect of muscle type also occurred (P≤0.040) for flavor attributes, in which GM and PM samples scored higher in off-flavor attributes compared with LL samples, including flavors such as liver-like, oxidized, and sour. An interaction between muscle type and days of age occurred for 2-pentyl-furan (P=0.021). One compound—3 hydroxy-2 butanone—was affected by muscle type (P=0.009). However, most compounds were affected by days of age (P≤0.046), in which compounds related to off-flavors increased in concentrations the most after 49 d. Additionally, discriminant function analyses were performed, suggesting the most effective aging time for individual steaks to be under 49 d when considering loadings for volatile compounds and flavor attributes corresponding with days of age. Overall, these data suggest individual packaging of GM, LL, and PM muscles is most optimal for up to 42 or49 d of age without a large impact from the presence of off-flavors, thus providing food service establishments the opportunity to individually package beef steaks for an extended period while maintaining consumer satisfaction through optimal flavor.

This study was conducted to investigate the effects of different stressors on physiological and innate immune variables in weaned dairy calves. Dairy steers [n = 40;10 ±1.8 kg body weight (BW)] were transported to the Calf Building at the USDA-ARS Livestock Issues Research Unit where they were housed in individual pens in an environmentally controlled room. Calves had ad libitum access to water and a starter ration. At arrival, calves were randomly allotted to four treatment groups (n = 10/treatment): 1) Control, 2) Transport (transported in a livestock trailer for 4 h), 3) Lipopolysaccharide (LPS; administered i.v. 0.10 µg /kg BW), 4) Vaccine (administered a Mannheimia Haemolyticatoxoid vaccine; OneShot, Zoetis). One day before application of stressors, indwelling jugular vein catheters and rectal temperature (RT) recording devices were placed in all calves. Whole blood was collected at -1, -0.5, 0, 1, 2, 3, and 4 h relative to application of stressors for serum, plasma, and hematology. There was a treatment × time interaction (P ≤ 0.01) for all hematology parameters except for hemoglobin and platelets. Monocyte, lymphocyte, neutrophil, basophil, and white blood cell concentrations and the neutrophil:lymphocyte ratio were reduced (P < 0.02) in calves administered LPS compared with all other treatments. For calves administered the Vaccine treatment, white blood cell and neutrophil concentrations and the neutrophil:lymphocyte ratio increased (P < 0.04) 4 h post-challenge compared with other treatments. There was a treatment × time interaction (P < 0.01) for the change in RT relative to baseline values. The change in RT increased following administration of LPS and peaked at approximately 3 h post-challenge before decreasing to near baseline values. In contrast, RT began to increase 3 h post-challenge in calves administered the Vaccine treatment, where the greatest RT values were observed at 6 h post-challenge. There was a treatment x time interaction (P < 0.01) for cortisol concentrations, where calves administered LPS produced the greatest increase in cortisol compared with all other treatments. There was a treatment x time interaction (P < 0.01) for tumor necrosis factor-a (TNF-a) and macrophage inflammatory protein-1b (MIP-1b). Concentrations of TNF-a remained greater in LPS and Vaccine calves compared with Control and Transport calves while MIP-1b concentrations remained omcreased for calves administered LPS compared with the other treatments. Results from this study suggest that common challenges experienced by dairy calves differentially influence physiological and immunological variables in weaned dairy calves.

The objective of this study was to determine the influence of lighting type and display duration on flavor development in multiple beef muscles. Paired beef top sirloin butts, strip loins, and tenderloins were collected from USDA Low Choice carcasses (Small00 to Small100 marbling score, n = 16). Subprimals were wet-aged in the absence of light for 7 d post-mortem at 0 to 4⁰C before being fabricated into 2.54 cm steaks representing the Gluteus medius (GM), Longissimus lumborum (LL), and Psoas major (PM). Steaks were packaged individually in vacuum rollstock packaging (VRP), and assigned to either light-emitting diode (LED) or fluorescent (FLUR) display cases for a display period of 0, 2, 6, or 10 d. All steaks were assigned to either trained descriptive panel analysis (n = 384) or volatile compound analysis (n = 384) and cooked to a medium degree of doneness (71⁰C). Trained descriptive panelists evaluated samples for beef flavor identity, brown/roasted, bloody/serumy, fat-like, liver-like, oxidized, umami, sweet, salty, bitter, sour, overall tenderness, and overall juiciness attributes. Two-way interactions occurred between lighting type and display duration, showing increased tenderness sooner during display for LED steaks, and lower umami intensity in FLUR steaks after 10 d (P < 0.001). Lighting and muscle type showed more tender LL and PM steaks in LED lighting (P ≤ 0.001). Lighting and display duration interactions also showed increased concentrations of 2,3- Butanedione under FLUR light and ethyl benzene under LED display (P ≤  0.043), while lighting and muscle type showed greater concentrations of alcohols and carboxylic acids in LL steaks under LED lighting (P ≤ 0.046). Discriminate function analyses were also used to evaluate relationships between trained sensory attributes and volatile flavor compounds. Nonetheless, lighting type showed no clear impact on beef flavor and volatile compounds of individually packaged beef steaks.

This study assessed how fresh beef tumbling without brine inclusion combined with aging would affect quality, biochemical attributes, and descriptive sensory scores of sirloin muscles. Paired gluteus medius (GM), biceps femoris (BF), and tensor fasciae latae (TFL) muscles from beef carcasses (n = 16) at 5 days postmortem were assigned to 0 or 120 min of tumbling, after which sections were aged 0 or 10 days. Tumbled GM (p < 0.001) and TFL (p < 0.01) muscles had increased objective tenderness compared to respective controls. Greater cook and initial purge losses were induced in all muscles with tumbling (p < 0.05), while thawing loss and purge loss with aging were similar (p > 0.05). Fragmentation of myofibrils was increased with tumbling and aging main effects (p < 0.001), although degradation of troponin T and desmin were primarily affected by aging only. In general, neither tumbling nor aging affected properties of collagen. Trained panelists assessed muscles aged 10 days for descriptive sensory scores including tenderness (myofibrillar, connective tissue, and overall), flavor (beef flavor identity, bloody/serumy, fat‐like, liver‐like, oxidized, umami, metallic, and sour), and juiciness (overall). Tumbled GM had greater myofibrillar tenderness than the control group (p < 0.05). Most sensory scores were unaffected by tumbling; however, tumbling increased oxidized and liver‐like flavors of GM and TFL, respectively, as well as decreased overall juiciness of BF (p < 0.05). These findings indicate tumbling combined with postmortem aging can improve tenderness of certain sirloin muscles like GM, although some impairments to flavor and juiciness could also occur. Practical Application The findings of this study are applicable to the beef industry to develop postharvest strategies to ensure sufficient tenderization of fresh beef sirloin muscles is achieved. However, the effectiveness of this process would differ between individual cuts, and minimizing possible impairments to flavor and juiciness would be critical.

The objective of this study was to evaluate antioxidant capacity in plasma of beef calves challenged with LPS. Following an initial feeding period of 40 d, steers (n = 32; 379 kg ± 30.7) were transported to the Livestock Issues Research Unit’s Bovine Immunology Research and Development Complex and challenged intravenously with LPS (0.25 µg/kg BW) on d 41. Blood samples were collected via jugular catheter at -2, 0, 2, 4, 6, 8, 10, 12, 18, 24, 36 and 48 h relative to the LPS challenge at 0 h. Blood samples were processed to isolate plasma for indicators of oxidative stress with a colorimetric assay to determine ferric reducing antioxidant power (FRAP) values via concentration of ferrous iron (µM). Data were analyzed as repeated measures using the GLIMMIX procedure of SAS. Antioxidant values did vary with time (P &lt; 0.001) being greater (P &lt; 0.05) at -2, 0, 2, 36, and 48 h. Antioxidant capacity was reduced at 6 and 8 h (P &lt; 0.05), with the least FRAP value observed at 8 h post-challenge. Antioxidant capacity increased (P &lt; 0.05) again at 10 h, showing similar (P &gt; 0.05) concentrations to those observed at 4 h. By 24 h post-challenge, plasma FRAP values increased (P &lt; 0.05) similar to initial values at -2, 0, and 2 h. It can be inferred that oxidative stress contributes to reduced antioxidant capacity, ultimately interfering with animal growth and productivity. While these values reflect the oxidative stress response to an acute endotoxin challenge, and a subsequent recovery returning to homeostasis within 24 to 48 h, they may also correlate with other physiological and immunological indicators associated with an acute endotoxin challenge.