Live and carcass production traits for progeny of an F1 USDA Prime - Yield Grade 1 carcass clone sire in comparison with progeny of popular reference sires

The cloning of beef carcasses that grade USDA Prime – Yield Grade 1 (P1) has produced a sire that ranked well against high performing bulls from multiple breeds. An F1 (P1 x P1) sire would ideally outperform its high performing parents. A terminal sire study was conducted comparing progeny of an F1 (P1 x P1) sire (AxG1) against progeny (heifers and steers) of four high performing sires of varying breeds {P1 (Alpha); Angus; Simmental; Angus x Simmental}. Production traits included morbidity and mortality frequencies, weaning weight, feedlot arrival weight, and days on feed; carcass traits included frequency of abscessed liver and lung health, quality and yield grade (YG) parameters, total carcass value, and carcass value per cwt. A completely randomized experimental design was used; data was analyzed using a mixed model with a fixed effect of sire and random effects of harvest date, sex, and pen. AxG1 sired heifers had the highest (P < 0.01) marbling score, the highest (P < 0.01) carcass value per cwt, and numerically had the lowest calculated yield grade and highest frequency of YG one carcasses. Steers sired by AxG1 had the least (P = 0.05) backfat thickness, lowest (P < 0.01) calculated yield grade, highest (P < 0.01) marbling score, highest (P < 0.01) frequency of USDA Prime carcasses, the highest (P < 0.03) total carcass value, and highest (P < 0.01) carcass value per cwt respectfully. Collectively, AxG1 steers and heifers exhibited the least 12th rib fat thickness and lowest USDA YG in addition to the largest longissimus muscle area, highest marbling score, and greatest frequency of
USDA Prime. These data suggest that AxG1 outperformed other high performing industry reference terminal sires in carcass quality and yield grade outcomes.