PRIMEONE SIRE COMPARISON IN THE BEEF X DAIRY PRODUCTION SYSTEM AND THE INFLUENCE OF FREEZING DURATION AND PACKAGING TYPE ON SENSORY OUTCOMES OF BEEF STEAKS

The objective of this study was to compare live and carcass grading outcomes of dairy cross progeny from a sire derived via carcass cloning to progeny from a competitive traditional purebred Angus sire. Semen was artificially inseminated into Jersey cows from an F1 sire (AxG1) derived from USDA Prime Yield Grade One carcass clones and a high-performance purebred Angus sire (Foundation). Calves were born at the dairy, raised in hutches on the dairy, and grown in a separate facility - all in the Texas panhandle. Cattle were later transported to Nebraska for finishing. Both steers and heifers were harvested at a commercial beef processor in Colorado and vision camera grading data was collected to assess carcass quality and yield outcomes. Continuous data were analyzed using the MIXED procedure; frequency data were analyzed using the GLIMMIX procedure. The fixed effect was sire and the random effect was harvest date. Additionally, least squares means were calculated using the LSMEANS option, and mean separation was completed using the PDIFF option. Treatment comparisons were tested for significance at α = 0.05. In live growth, calves sired by Foundation were heavier (P < 0.01) both when they entered (396.1 vs 383.0 kg) and exited (590.1 vs 568.8 kg) the Nebraska feedyard. Similarly, calves sired by Foundation had heavier (P < 0.01) hot carcass weights than AxG1 (374.9 vs 361.4 kg). No difference (P = 0.27) was detected
between sires for longissimus muscle area (96.6 vs 95.7 cm2) or marbling score (Moderate26 vs Moderate20). Moreover, AxG1 sired calves had greater (P < 0.01) longissimus muscle area per unit of carcass weight (26.7 vs 25.9 cm2/100kg). Calves sired by AxG1 were leaner (P < 0.01) than those sired by Foundation as evidenced by less 12th rib subcutaneous fat (1.11 vs 1.26 cm) coupled with lower calculated yield grades (2.37 vs 2.59). Moreover, calculated empty body fat was greater (P < 0.01) for Foundation sired carcasses than those sired by AxG1 (29.9 vs 28.9 %). Total carcass value differed (P < 0.01) with Foundation sired calves having the highest valued carcass, compared to calves sired by AxG1. Foundation sired calves were represented by a greater (P < 0.04) percentage of USDA Prime carcasses (26.32 vs 17.79 %) whereas AxG1 sired calves had a greater (P < 0.05) percentage of USDA Choice carcasses (77.74 vs 69.48 %). AxG1 sired calves were represented by a greater (P = 0.04) percentage of Yield Grade 1 carcasses (27.48 vs 19.25 %). No difference in frequency of Yield Grade 2 (55.40 vs 57.95 %) or 4 (1.41 vs 1.0 %) carcasses was observed between sires. Frequency of Yield Grade 3 carcasses was greater (P < 0.01) for Foundation compared to AxG1 (23.94 vs 13.58 %). Carcass outcomes suggest that progeny sired by Foundation were of slightly greater mass whereas progeny sired by AxG1 were of slightly higher yield. Our objective was to evaluate the sensory traits of beef steaks originating from two muscles packaged via two methods and subjected to four freezing durations. Paired strip loins (USDA IMPS #180) and top sirloin butts (USDA IMPS #184) from USDA Choice carcasses (n = 15) were cut into 2.54-cm-thick steaks represented by the M. longissimus lumborum (LL) and M. gluteus medius (GM). Individually vacuum packaged steaks were transported from Canyon, TX to Fayetteville, AR, and re-packaged according to randomly assigned treatment: vacuum (VAC) or overwrap (OW) packaging. After 3d of continuous exposure to light emitting diode retail display, steaks were separated by storage treatment: 6d fresh; 1-week, 1-month, 6-month, and 9-month frozen (-20°C). After each storage duration was completed, steaks were transported back to Canyon, TX for trained sensory panels (n = 75). During each panel, four steaks (VAC LL, VAC GM, OW LL and OW GM) were cooked to 71°C using clamshell grills, then cut into steak thickness x 1-cm cubes. Panelists evaluated samples for beef flavor identity, brown/roasted, bloody/serumy, fat-like, umami, overall tenderness, overall juiciness, and off flavors (bitter, cardboard, fishy, liver-like, oxidized, rancid, refrigerator/stale, and sour). Statistical analyses were conducted using the procedures of SAS. Least squares means were calculated using the LSMEANS option, and mean separation was completed using the PDIFF option with the Bonferroni option. Treatment comparisons were tested for significance using PROC GLIMMIX with α = 0.050. Fixed effects were muscle, package type, and duration, and the random effect was panel, ordered served within the sensory panel, and peak temperature. Muscle by storage duration interaction was observed for beef flavor identity, oxidized and sour (P ≤ 0.039). Trained panelists did not detect differences in beef flavor for LL across duration, however GM steaks had lower ratings at 6 and 9 months frozen. Panelists rated GM greater (P = 0.039) than LL for oxidized and sour flavors after 9 months frozen storage. The interaction (P = 0.024) between packaging type and muscle indicated OW GM was rated lower for juiciness than all other muscle/packaging types. An interaction was observed between package type and cold storage duration for beef flavor identity, oxidized, refrigerator-stale and sour flavors (P ≤ 0.009). Steaks VAC packaged had higher beef flavor ratings at 9 months frozen storage, whereas beef flavor of OW packaged steaks decreased (P = 0.009) as duration increased. Steaks in OW packaging increased (P ≤ 0.004) in oxidized, refrigerator/stale, and sour flavor ratings as storage duration increased. Steaks VAC packaged were rated more sour (P = 0.004) at 6 and 9 months frozen storage than OW. Brown roasted and fishy off-flavor ratings were higher (P ≤ 0.002) for OW steaks than VAC steaks. Bloody serumy, umami flavors, and tenderness outcomes were rated higher (P ≤ 0.006) for VAC steaks than OW steaks. Fat-like, umami flavors, and tenderness were rated higher (P < 0.001) for LL steaks whereas liver-like, rancid, and refrigerator/stale off-flavors were rated higher (P ≤ 0.008) for GM steaks. Cardboard, bitter, and rancid off-flavors were higher after 9 months of frozen storage compared to fresh steaks (P ≤ 0.012). Overall tenderness and juiciness of fresh and 9 months frozen steaks did not differ (P > 0.050). In conclusion, there was no detrimental effect on tenderness, juiciness, or flavor when freezing VAC steaks for up to 9 months. Steaks packaged OW were less tender, and the OW GM was less juicy when compared to VAC steaks. Undesirable off flavors were higher in GM vs. LL, OW vs. VAC and after longer cold storage durations.