*While the full article for this executive summary is currently under peer review, these initial findings are being made available on BeefResearch.org to enable the industry to act on the research, inform the scientific community of ongoing work, and help prevent duplication of research efforts. Once peer review is complete, a link to the published article will be added to this summary.
KEY TAKEAWAYS
- Lubabegron fumarate has minimal impact on sensory evaluation and shear force values when standardized by quality grade.
- A reduction in marbling score, and thus distribution of quality grade was apartment in lots of cattle fed Lubabegron fumarate.
BACKGROUND
The FDA's approval of Lubabegron fumarate for use in beef cattle has led to widespread use in the feedlot sector. The novel label approval for reduction of ammonia emissions per pound of live or carcass weight by Lubabegron fumarate enters previously uncharted territory for β-agoagonists and other growth promotion technologies. This label indicates a movement to an industry focus on sustainable beef and environmental impact reduction, as traditional approvals for β-agonist are for increased average daily gain and gain to feed ratio. Moreover, little research has been performed to understand how this novel β-agonist affects beef quality, especially on a representative population of cattle across the United States. Therefore, the goal of this study was to understand the effects of Lubabegron fumarate on the eating experience of beef.
Methodology
Specific pens of cattle, either fed Lubabegron fumarate (LUB), or not, were identified before harvest. Cattle were located across three major cattle-feeding regions: High plains of Texas (30%), western Kansas (45%), and the upper Midwest (25%) to ensure the sample of cattle represented much of the feedlot industry. Pens of cattle were traced through beef processing facilities, and a subsample of the lots (N= 200) were selected for collection. The subsamples were evenly divided among LUB or control treatment, and samples grading Low choice, and Top Choice. Loins were fabricated to 4-inch chunks, and aged 3-, 7-, 14-, 21-, 28-, and 35-days postmortem. Chunks were vacuum sealed, boxed, aged at 1-3° C until the assigned aging period, sliced into 1 in steaks, imaged for steak dimension analysis, then frozen. Trained panelists at Texas Tech University were fed an even distribution of 14 and 28 d, Low Choice and Top Choice, and LUB or control samples on each trained sensory panel. Panelists evaluated 12 attributes, and scores were averaged across each panelist. A separate steak was utilized for Warner Bratzler and slice shear force. Data were analyzed using R statistical software.
It must be noted this was not a controlled study, and while all effort was made to obtain paired lots of cattle similar in type, differing in LUB treatment, cattle came from separate feedyards, and thus likely had differences in days on feed, diet type, etc. Nonetheless, there are noticeable trends in the carcass data, particularly marbling and percentage of each quality grade. Control lots had notably higher percentage of cattle grading in the Top Choice category (6.2%), and less cattle grading Select (8.2%) in comparison to LUB fed cattle. Across all lots, marbling score was 21 degrees higher in control lots. It should be noted this occurred with similar average ribeye areas, backfat, and final yield grades.
In terms of trained sensory analysis, there were no two- or three-way interactions between LUB treatment, quality grade, and aging period (P > 0.41) for any attribute. Therefore, only the main effects are interpreted. Furthermore, there were no differences between the control and LUB treatments for any sensory attribute (P > 0.17). While trained panelists found no differences based on β-agonist treatment, panelists did find differences among aging periods and quality grades. Steaks aged 28 days were found to be more tender than samples aged 14 d. Furthermore, Premium Choice samples were rated higher for tenderness, juiciness, fat-like, and umami than Low Choice samples. Moreover, cook loss was not significant for any interaction or main effect (P > 0.17).Trained sensory multivariate analysis showed a similar trend. There were no two- or three-way interaction in the multivariate analysis of variance (P >0.61), or main effect differences for LUB treatment (P = 0.41). There were, however, differences in aging period and quality grade in a multivariate space (P < 0.001). Those differences are driven by the attributes determined to be different in a univariate space. Therefore, panelists were able to determine differences among quality grades in aging periods, although did not determine control and LUB samples to be different for any trait. This provides further confidence that LUB has minimal effect on overall eating quality in comparison to the control.
There were no two- or three-way interactions among treatment, aging period and quality grade for Warner-Bratzler Shear force (P > 0.42). Control and LUB samples were not different (P = 0.71) for Warner-Bratzler. In terms of slice shear force, there was no three-way interaction, however, there was an interaction between treatment and quality grade. Control Top Choice samples resulted in lower slice shear force values than LUB fed Top Choice or Low Choice samples (P = 0.01) while control Low Choice was not different from any other treatment combination. However, all values for Warner-Bratzler, or slice shear force are under the values determined by ATSM to be rated “tender” and are below the threshold for a detectable tenderness difference, indicating a lack of biological significance.
Main effects were interpreted for Warner-Bratzler and slice shear force for aging period. Both Warner-Bratzler and slice shear force values decreased as aging period increased (P < 0.001). In both methods, 3-day samples resulted in the highest shear force values, while 28 and 35 d had the lowest shear force values.
There were no differences among treatments for any steak location for steak area (P > 0.20), length (P > 0.17), width at 25% (P > 0.23), 50% (P > 0.30), 75% (P > 0.32), and 87.5% (P > 0.37). Moreover, each steak was averaged across the carcass, and overall steak area, length, and width measurements were evaluated irrespective of location. Similarly, all measurements had no differences (P > 0.20).
Implications
As a whole, Lubabegron had little impact on overall eating experience of beef products when standardized by quality grade. However, the negative impact of marbling score by Lubabegron, along with the impact of marbling on eating experience, cannot be disregarded. The widespread decrease in availability of highly marbled beef caused by using Lubabegron should be a consideration of the use of the product industry wide. Nonetheless, within the scope of eating experience, especially tenderness, Lubabegron’s effect on meat quality is minimal.