Background 

The U.S. fed-beef industry has recently experienced a shift in supply as a vast majority of dairy farmers have had to seek additional value in the terminal bound, dairy-bred animal due to record low milk prices in current years. Dairies have introduced beef genetics into their population by breeding their dairy females to beef bulls with the goal of generating a phenotype resembling beef type cattle in hopes of their product being undifferentiated into the larger population at the time of slaughter. Product fabricated from native beef and dairy type cattle is widely understood but a number of questions surround the carcass composition, eating quality characteristics and immunohistochemical differences of beef x dairy cattle especially in comparison to their parental cattle types.

The objectives of this study were to identify beef quality differences between cattle types, specific to beef x dairy crossbred cattle, representing a range of quality grades, in order to characterize and understand the value of the shifting segment in the U.S. fed beef supply. Objectives were distinguished by evaluating: 1) tenderness, juiciness and sensory attributes for palatability, 2) color, pH and dimensionality assessing retail display, 3) immunohistochemistry characteristics by quantifying muscle fiber type and diameter and 4) flavor by exploring chemical composition.

Methodology 

Carcasses (n = 560) were selected at 3 separate commercial beef packing facilities on the basis of known cattle type on a lot basis: Native beef, Beef x dairy or Dairy, represented equally across 4 different USDA Quality Grades: Prime, Upper 2/3 Choice, Choice and Select. Strip loin sections (approximately 5cm in thickness) were collected from both sides of the carcass and then aged 14 days at Texas Tech University. Simultaneously to strip loin collection, a sample from the longissimus dorsi (.75cm x .75cm x 1.5 cm) was stored at -80°C for later myosin heavy chain determination. After aging, from each pair of strip loins 4 – 2.54cm steaks were fabricated and stored at -20°C. At fabrication, steaks were assigned to either shear force, trained sensory, consumer sensory or retail display (only USDA Choice carcasses). Shear force steaks were also utilized for dimensionality and additional pieces from each strip section were allocated to REIMS and pH analysis.

findings

Analysis of carcass characteristics, trained and instrumental color analysis, dimensionality, shear force, REIMS along with trained and consumer sensory panels would indicate that beef x dairy cattle produce carcass results and meat quality differences that are an intermediate to that of native beef and dairy type cattle. Beef x dairy cattle produced heavier muscled and shorter carcasses in comparison to dairy type cattle, along with leaner carcasses that calculate a lower yield grade comparatively to native beef carcasses. Strip loin steaks from beef x dairy cattle performed similarly to native beef as they were the more sustainable in the retail case than dairy type cattle. Shear force and sensory analysis indicated strip loin steaks from beef x dairy cattle were similar to dairy type that were the most tender and had the most ideal flavor attributes. Additionally, dairy type cattle had a greater proportion of MHC Type I fibers and the smallest fiber area agreeing with our results that they produce the most tender product, while beef x dairy cattle surprisingly had the largest muscle fiber area across all three myosin heavy chain isoforms. To conclude, beef from beef x dairy crossbreds could serve as an upgrade to their contemporary cattle types in specific meat quality areas when compared to either native beef or dairy type cattle.

implications

Terminal bound beef x dairy crossbreds should be of significant value to dairy farmers and consequently feeders across the U.S. in comparison to dairy type cattle as their fabricated product at slaughter is in many ways undifferentiated to native beef cattle. As a greater population of beef x dairy cattle continue to enter the fed-beef supply their product could serve as an upgrade to their contemporary cattle types in aspects of carcass composition and eating quality. Our findings indicate that beef x dairy cattle produce a product that is similar to native beef cattle in muscling, carcass length and retail display attributes while similar to dairy type cattle from the standpoint of trimness, tenderness and flavor. These differences could allow for beef x dairy cattle to be valued differently than their contemporary cattle types to feeders, packers and retailers in the future, as their product offers distinct advantages.