Characterizing carcass conformation, meat quality attributes and muscle fiber properties of beef x dairy crossbred cattle

The objective of this study was first, to identify beef quality differences among beef × dairy cattle relative to native beef and dairy cattle, across a range of quality grades, and second, to characterize and understand the true value of this segment in the United States fed-beef supply. Carcasses (n = 560) were selected at 3 separate commercial beef packing facilities based on known cattle type: native beef, beef × dairy or dairy, represented across 4 different USDA Quality Grades: Prime, Upper 2/3 Choice, Choice and Select. Strip loin sections (approximately 5 cm in thickness) were collected from both sides of the carcass and then aged 14 days. At the same time, samples from the longissimus dorsi (0.75cm × 0.75cm × 1.5cm) were frozen for future immunohistochemical analysis (n = 113). After aging, from each pair of strip loins 4 – 2.54 cm steaks were fabricated and stored at -20°C. At fabrication, steaks were assigned to either shear force, trained sensory, consumer sensory or color panel (only USDA Choice carcasses). Shear force steaks were also utilized for dimensionality images and additional pieces from each strip section were allocated to Rapid Evaporative Ionization Mass Spectrometry (REIMS) and pH analyses. Data were analyzed in R (version 4.0, R Core Team, Vienna, Austria) as a completely randomized experiment with a 3×4 factorial arrangement of treatments. Cattle type, USDA Quality Grade, and their interaction (when appropriate) were included as fixed effects. All carcass traits were impacted by cattle type (P < 0.01). Cattle type affected myosin heavy chain isoform IIA proportion (P ≤ 0.01) and beef × dairy cattle had the largest mean cross-sectional area (P ≤ 0.05). Cattle type impacted pH, all trained color panel, L* and a* values and shear force measurements (P < 0.01). Trained sensory analysis indicated tenderness, juiciness and flavor attributes of sour, metallic, fat-like, buttery, liver and oxidized were affected by cattle type (P < 0.01). Consumer sensory analysis also showed tenderness was affected by cattle type (P < 0.01). These results indicate beef × dairy cattle improved aspects of carcass composition when compared to either other cattle type, color stability was preferred to dairy cattle along with recognized improvements in tenderness and flavor performance when compared to native beef. Secondly, the same aforementioned sampling procedures (n = 530) and analyses were utilized to determine the effect of Angus or Continental influenced sires on meat quality characteristics of beef × dairy cattle and compared to native beef and dairy-type cattle (analyzed as a 4 × 4 factorial). Continental influenced sires improved REA relative to dairy type cattle along with trimness and overall yield grade compared to native beef (P < 0.05). Additionally, Angus sires decreased fatness compared to native beef (P < 0.05). Continental influenced beef × dairy cattle produced the least myosin heavy chain IIX fibers and the largest cross-sectional area of myosin heavy chain I, IIA and total fiber area (P < 0.05). Initial color and color stability of strip loin steaks from Angus sired beef × dairy cattle was more ideal relative to Continental influenced sires (P < 0.05). Angus sires also improved tenderness compared to Continental influenced sires as quantified by trained sensory analysis and shear force measurements (P < 0.05). Finally, trained sensory flavor attributes indicated dairy influenced cattle were more ideal than native beef (P < 0.05). To conclude, both Continental-influenced and Angus sired bulls improved characteristics of carcass composition relative to either of their parental breed types and initial color and color stability of ABD was preferred to dairy-type and CIBD cattle. Additionally, both sire types improved tenderness and showed more ideal flavor profiles comparatively to native beef.