Background With rising concerns regarding the effects of red meat on human and environmental health, a growing number of livestock producers are exploring ways to improve production systems. A promising avenue includes agro-ecological practices such as rotational grazing of locally adapted ruminants. Additionally, growing consumer interest in pasture-finished meat (i.e., grass-fed) has raised questions about its nutritional composition. Thus, the goal of this study was to determine the impact of two common finishing systems in North American bison—pasture-finished or pen-finished on concentrates for 146 d—on metabolomic, lipidomic, and fatty acid profiles of striploins (M. longissimus lumborum). Results Six hundred and seventy-one (671) out of 1570 profiled compounds (43%) differed between pasture- and pen-finished conditions (n = 20 animals per group) (all, P < 0.05). Relative to pasture-finished animals, the muscle of pen-finished animals displayed elevated glucose metabolites (~ 1.6-fold), triglycerides (~ 2-fold), markers of oxidative stress (~ 1.5-fold), and proteolysis (~ 1.2-fold). In contrast, pasture-finished animals displayed improved mitochondrial (~ 1.3-fold higher levels of various Krebs cycle metabolites) and carnitine metabolism (~ 3-fold higher levels of long-chain acyl carnitines) (all P < 0.05). Pasture-finishing also concentrated higher levels of phenolics (~ 2.3-fold), alpha-tocopherol (~ 5.8-fold), carotene (~ 2.0-fold), and very long-chain fatty acids (~ 1.3-fold) in their meat, while having lower levels of a common advanced lipoxidation (4-hydroxy-nonenal-glutathione; ~ 2-fold) and glycation end-product (N6-carboxymethyllysine; ~ 1.7-fold) (all P < 0.05). In contrast, vitamins B5, B6, and C, gamma/beta-tocopherol, and three phenolics commonly found in alfalfa were ~ 2.5-fold higher in pen-finished animals (all P < 0.05); suggesting some concentrate feeding, or grazing plants rich in those compounds, may be beneficial. Conclusions Pasture-finishing (i.e., grass-fed) broadly improves bison metabolic health and accumulates additional potential health-promoting compounds in their meat compared to concentrate finishing in confinement (i.e., pen-finished). Our data, however, does not indicate that meat from pen-finished bison is therefore unhealthy. The studied bison meat—irrespective of finishing practice—contained favorable omega 6:3 ratios (< 3.2), and amino acid and vitamin profiles. Our study represents one of the deepest meat profiling studies to date (> 1500 unique compounds), having revealed previously unrecognized differences in animal metabolic health and nutritional composition because of finishing mode. Whether observed nutritional differences have an appreciable effect on human health remains to be determined. Graphical abstract

Brassica cover crops have been widely used for improving soil health and as a feed resource for grazing cows, but their use in backgrounding diets is unknown. The objective of this study was to determine the impact of feeding a brassica cover crop mixture during backgrounding on beef palatability. Thirty steers were assigned to one of two dietary treatments during backgrounding with (1) ad libitum access to freshly cut brassica cover crop forage (CC) containing radish, turnip, rapeseed, and rye grass, or (2) common Midwestern dry lot backgrounding diet (CON). The steers were transitioned to a common finishing diet after backgrounding. Striploins were collected after harvest, and were analyzed for evaluation of the Warner–Bratzler shear force (WBSF), collagen content, autolysis of calpain-1, proteolysis of desmin, and troponin-T; in addition, the tenderness, juiciness, and flavor evaluated by a trained sensory panel. A treatment x day interaction was observed for WBSF (p = 0.02). Steaks from the CON diet were less tender than CC steaks on days 3 and 7, but did not differ on days 14 and 21. Feeding a brassica mixture cover crop during the backgrounding phase of production did not impact the collagen content, autolysis of calpain-1, or proteolysis of desmin and troponin-T. Thus, additional investigation into the mechanisms responsible for the differences observed in instrumental tenderness is warranted.

ObjectivesWhole muscle cuts from cows are often less tender than cuts from young fed beef due to increased collagen cross-linking associated with animal age. The injection of a rinse solution through the carotid artery following exsanguination has been shown to improve tenderness. The objective of this study was to compare the effect of a post-harvest rinse of an isotonic solution through the circulatory system on tenderness of steaks from cows.Materials and MethodsCows (n = 28) were randomly assigned to carcass treatments. The carcass treatments consisted of non-rinsed control (n = 14) and a rinsed (n = 14) treatment, where a chilled isotonic solution (MPSC, Inc., St. Paul, MN) was rinsed through the carotid artery and veins following exsanguination. The isotonic solution consisted of water, glucose, maltose and phosphates. Both control and rinsed treatments were electrically stimulated. At 2 d postmortem, strip loins were removed from one side of each carcass. Strip loins were fabricated into 2.54 cm steaks at 3 d postmortem and objective color measurements (L*, a* and b*) were recorded on a single steak after a 30-min bloom period. Steaks were vacuum packaged and aged at 4°C for 7, 14, and 21 d. Following aging, steaks were frozen (–20°C) for future analysis. Warner-Bratzler Shear Force (WBSF) was used to measure tenderness. Frozen steaks were thawed at 4°C for 24 h before cooking. Internal temperature was monitored on all steaks using a digital thermometer that was placed in the center of each steak. Steaks were cooked on an electric clamshell grill to an internal temperature of 71°C. Peak cook temperature was recorded for each steak. Following cooking, steaks were cooled at 4°C and allowed to equilibrate to room temperature (20°C). Six cores (1.27 cm) were removed from each steak and sheared perpendicular to the muscle fiber orientation. The peak force was recorded for each core and the average calculated for each steak. Data were analyzed using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). Shear force data were analyzed as a repeated measure with time and treatment as fixed variables. Color data were analyzed as a completely randomized design using treatment as the fixed variable. Statistical significance was considered at an α of P < 0.05 and trends at 0.05 ≤ P < 0.10.ResultsThere was no interaction (P = 0.6068) between treatment and postmortem aging day. Steaks from the rinsed treatment were more tender (P = 0.0005), than steaks in the control treatment (3.51 ± 0.168 kg vs. 4.41 ± 0.174 kg, respectively). Postmortem aging influenced (P = 0.0310) tenderness. Steaks aged 7 d were less tender (P = 0.0087) than steaks aged for 21 d (4.18 ± 0.155 kg vs. 3.72 ± 0.156 kg, respectively), while 14 d steaks did not differ (P > 0.05) from those aged 7 or 21 d. Objective color was not impacted by rinse treatment (P > 0.05).ConclusionThese data suggest that the application of a post-harvest rinse with an isotonic solution through the circulatory system improves the tenderness of cow steaks but does not influence objective color.

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The objective of this study was to determine the impact of environmental temperature during striploin and sirloin transport on moisture loss, color, and tenderness. Cases of striploins (n = 24) and sirloins (n = 24) were alternately placed on two pallets. Each pallet was placed on a refrigerated truck pre-chilled to -2.2°C (-2.2FT) or 3.3°C (3.3FT) and product was transported for 12 h prior to arriving at the South Dakota State University Meat Laboratory. One subprimal was subset from each case for further analysis. Subprimal purge loss was measured prior to fabrication into eight 2.54cm steaks. Steaks were overwrapped and packaged in modified atmosphere packaging prior to a second transport. Four steaks from each subprimal were placed on one of two pallets. Each pallet was placed on a pre-chilled refrigerated truck set at -2.2°C or 3.3°C. The steaks were transported for 12 h prior to returning to the Meat Laboratory. Steaks were utilized for the evaluation of color, cook loss, purge loss, and Warner-Bratzler shear force (WBSF). Subprimal purge loss was increased for 3.3FT sirloins compared to -2.2FT (P = 0.0362). L* values for -2.2FT strip steaks were increased (P &lt; 0.0001) and purge loss decreased (P = 0.0188) compared to 3.3FT steaks. L* values and fresh steak purge loss for 3.3FT sirloins were increased (P = 0.0356 and P = 0.0460 respectively) compared to -2.2FT steaks. These data indicate varied responses to temperature differences based on subprimal. Thus, a universal recommendation for all meat products could not be made and further investigation into the impacts of transportation temperatures on various meat products is vital to optimization of the meat supply chain.