Preharvest health treatment effects on post-harvest tenderness, lean color, and antioxidant capacity

Authors: BARKER, SAM - Texas Tech University; LEGAKO, JERRAD - Texas Tech University; HALES, KRISTIN - Texas Tech University; LONG, NATE - Texas Tech University; Carroll, Jeffery - Jeff Carroll; Sanchez, Nicole; Broadway, Paul

Submitted to: American Meat Science Association Conference Reciprocal Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The objective of this study was to evaluate the effect of metaphylactic treatment in response to diagnosed Bovine Respiratory Disease (BRD) at the feedlot on the tenderness, color stability, and oxidative status of these cattle post-harvest. A subset of cattle (n=72) were selected for this study based on number of metaphylactic treatments in response to BRD (Control = 0 treatments; TRT1 = 1 treatment; TRT2 = 2 treatments). Cattle within the study were evaluated daily and treated as needed by determination of rectal temperature (> 37.5 °C) and clinical illness score. Treatments included a negative control, or subcutaneous administration of either florfenicol, ceftiofur, or tulathromycin. Additionally, whole blood was collected at 3 intervals- upon feedlot arrival, 112 d, and 245 d. On d 246, cattle were shipped to a commercial processing facility, and at 48 h postmortem, striploins from selected steers were collected, immediately sectioned into quarters, and randomly assigned to aging treatments (7, 14, 21, 28 d). A face steak was also removed from the most anterior end of each strip loin, vacuum packaged, and frozen for subsequent analyses. Following assigned aging intervals, 3 steaks were cut from each quarter, vacuum packaged, and frozen for analyses. Quarters designated to 14 d had 2 additional steaks assigned to retail display. Retail display steaks were packaged in overwrap and displayed in coffin-style cases to be evaluated for redness and % discoloration by trained panelists, and L*, a*, and b* values for 6 d. Slice sheer force was evaluated on steaks representing every carcass and aging point. Furthermore, ferric reducing antioxidant power (FRAP) was determined via colorimetric assay on plasma from 3 time points and 48 h postmortem tissue. Repeated measures and a split-plot design were used to evaluate FRAP and color evaluations, as well as tenderness, respectively. Correlation coefficients were also determined across all variables mentioned. An interaction between treatment number and hour of display occurred for steak redness (P = 0.036). Throughout the display period, cattle receiving treatment showed steaks which were consistently more red than control samples (P < 0.05). However, when evaluating tenderness, there were no interactions or treatment differences (P = 0.286). Still, as days of age increased, SSF values decreased (P < 0.001). In plasma and 48 h post-mortem tissue, FRAP values showed an interaction between treatment number and sample timing (P = 0.016). At the starting and final time points, plasma samples increased in antioxidant capacity as metaphylactic treatment number increased (P < 0.05). Samples evaluated on the middle time point, as well as post-mortem tissue, did not differ (P > 0.05). Correlation coefficients showed a positive correlation between final FRAP values in plasma and redness at 0 and 6 d during retail display (P = 0.01) suggesting that as antioxidant capacity increased pre-harvest, post-mortem steak redness during display also increased. These data suggest that pre-harvest treatment of illness may affect antioxidant capacity and oxidative stress markers in vivo, ultimately impacting meat quality during retail display. This study also implies that any reduction in usage of metaphylactic drugs or promotion of alternative technologies during animal production may have significant effects on meat quality.