PSIV-19 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

Abstract

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 exhibit heterosis and 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, and feedlot arrival weight; carcass traits included edible liver and normal lung frequencies, hot carcass weight, longissimus muscle area, 12th rib fat thickness, and marbling score. 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. Feedlot arrival weight, frequencies of morbidity and mortality, 12th rib fat thickness, and frequency of grading Certified Angus Beef or USDA Select did not differ (P ≥ 0.16) between sires. Weaning weight and frequency of normal lungs tended (P ≤ 0.08) to differ amongst sires. Differences in hot carcass weight (P < 0.01), longissimus muscle area (P < 0.01), marbling score (P < 0.01), and frequencies of normal lungs (P < 0.01) was detected among sires. Additionally, sire differences in USDA yield grade (P < 0.01), and frequencies of carcasses grading USDA Prime (P < 0.01) and USDA Choice (P < 0.01) were observed. AxG1 progeny exhibited the least 12th rib fat thickness and lowest USDA yield grade in addition to the largest longissimus muscle area, highest marbling score, and greatest frequency of USDA Prime. These data suggest that AxG1 competed extremely well against other high performing industry sires.