Effects of forage level in feedlot finishing diets on carcass characteristics and palatability of Jersey beef1,2

Abstract

Jersey cattle are known for producing carcasses with a greater amount of marbling, but they require more days on feed to achieve acceptable market weights compared with other breeds. The objective of this study was to evaluate the effect of dietary forage (12 vs. 24% sudangrass:alfalfa hay, DM basis) in steam-flaked, corn-based finishing diets on carcass characteristics, beef palatability, and retail color stability of steaks from Jersey beef compared with conventionally fed commodity beef strip loins (COM) of identified quality (Choice(-) and Select(+)). Jersey steers (n = 77) were blocked by BW and randomly assigned to 1 of the following treatments for a 383-d trial period: Jersey low 12% (JL; n = 38) or Jersey high 24% (JH; n = 39) forage (DM basis). A comparison group was selected from conventionally fed cattle on the same day of slaughter as the Jersey treatments, and strip loins from USDA Select(+) (COM; n = 20) and Choice(-) (COM; n = 20) were removed for data analysis. Seventy-two hours postmortem, strip loins were removed, vacuum-packaged, and aged at 3°C for 18 d postmortem. After the aging period, steaks from the LM were sliced, vacuum-packaged, and frozen (-20°C) until analyzed. Jersey steaks had reduced (P < 0.05) Warner-Bratzler shear force values compared with COM steaks. Trained sensory panelists rated JL greater (P < 0.05) for initial and sustained tenderness and initial juiciness than COM, whereas JH was intermediate. As expected, marbling was greater (P < 0.05) for both JL and JH compared with COM, and trained sensory panel sustained juiciness, beef flavor intensity, and overall acceptability scores were greater (P < 0.05) for both JL and JH compared with COM; however, no differences (P = 0.14) were reported for consumer tenderness and flavor. Objective color (L*, a*, b*) measurements decreased (P < 0.05) over time across treatments. There were no differences among treatments for lightness (L*); however, overall during retail display JL were less (P < 0.05) red (a*) and yellow (b*) than JH and COM. Subjective color scores indicated both JL and JH were less red (P < 0.05) than COM. Steaks from Jersey were equal to and on some measurements more desirable than steaks from COM carcasses for both color stability and palatability. These results suggest that dietary forage level had minimal effects on carcass characteristics and beef palatability. However, feeding a low-forage diet decreases input cost and potentially results in a greater valued carcass. Finishing long-fed (383 d) Jersey steers can meet beef industry expectations with respect to quality grade.

Effect of Ensiled Mulberry Leaves and Sun-Dried Mulberry Fruit Pomace on Finishing Steer Growth Performance, Blood Biochemical Parameters, and Carcass Characteristics

“…Moisture, protein, and ash percentages were similar between the three treatment groups; however, intramuscular fat content was significantly higher in the CONT group than in the EML and SMFP groups. A previous study showed that WBSF values are negatively correlated with marbling scores and intramuscular fat content, indicating that as intramuscular fat decreases, WBSF values increase and steaks become tougher [19]. However, our results revealed that there were no differences in WBSF values, even at the lowest intramuscular fat content, in the EML and SMFP groups.…”

“…Cooking loss, expressed as a percentage of weight loss, was calculated from the ratio between the initial weight (before cooking) and the final weight (after cooking). At least six 1.27-cm-diameter pieces were removed from each steak parallel to the muscle fiber orientation [19]. The pieces were sheared perpendicular to the muscle fiber orientation using a shear device (Warner-Bratzler Meat Shear 2356X).…”

Genetic, management, and nutritional factors affecting intramuscular fat deposition in beef cattle — A review

“…American Wagyu steers fed a high-corn diet had greater fat accumulation than did animals fed a hay-based diet [ 120 ]. Similarly, dietary forage level affected MS. Jersey steers fed a low forage diet (6% Sudan grass, 6% alfalfa hay and 63.15% steam-flaked corn, dry matter [DM] basis) in a feedlot finishing diet had greater MS in the strip loin than did animals fed a high forage level diet (12% Sudan grass, 12% alfalfa hay and 51.20% steam-flaked corn) [ 121 ]. The effects of roughage/concentrate ratio on body fat deposition and the expression of angiogenic and adipogenic factors in adipose tissue have been examined in fattening Wagyu steers [ 122 ].…”

Review: Enhancing intramuscular fat development via targeting fibro-adipogenic progenitor cells in meat animals

“…Compared with the hay-based diet, corn-based diet can increase glucose uptake in intramuscular adipocytes, thus increasing IMF contents in America Wagyu (Chung et al, 2007) and Barrosã bulls, but not Alentejana bulls under the same condition (Costa et al, 2013). Conversely, haybased diet in the finishing stage generates lower marbling in Jersey steers (Arnett et al, 2012).…”