105 Use of cloning in beef production - the WTAMU PrimeOne Project.

Cloning is a technology by which genetic material can be salvaged and replicated for future herd improvement. Carcasses that grade USDA Prime – Yield Grade 1 (P1), represent a rare and antagonistic outcome and are a goal for terminal sire selection. The WTAMU PrimeOne project resulted in two bulls and three heifers born in 2012–2014 through somatic cell nuclear transfer from carcasses that graded P1. Mating of a crossbred bull (14% Zebu, 86% Angus; Alpha) to three identical heifers (Gammas) subsequently produced progeny (AxGs) via embryo transfer. Alpha progeny (steers and heifers) were compared against progeny of three purebred (Angus; Charolais; Simmental) reference sires in a terminal sire test. Live production traits and carcass traits were measured. A completely randomized experimental design structure was used; data were analyzed using a mixed model with sire as the fixed effect and harvest date, sex, and pen as random effects. For live cattle traits: Alpha progeny were the lightest (P = 0.03) in weaning weight (kg), tended (P = 0.08) to have the lowest frequency of morbidity, and Alpha-sired heifers tended (P = 0.07) to have the heaviest weight (kg) at feedlot arrival. For carcass traits: Alpha-sired heifers and steers had the largest (P < 0.01) longissimus muscle area next to the Charolais sire, Alpha-sired steers had the lowest (P P P < 0.01) for steers; Alpha-sired steers had the greatest value per cwt. Progeny data from Alpha and an AxG sire (AG1) is being used to generate EPDs for WTAMU PrimeOne cattle. These data indicate Alpha progeny performed comparably to high performing reference sires from multiple breeds for terminal sire production traits. [ABSTRACT FROM AUTHOR]