280 Relationship of gene markers to residual feed intake, ADG, and marbling of four years of MSU Steer-A-Year steers

Abstract

Feeding cattle is one of the largest expenses in beef production systems. Genetic testing has been proposed as a tool to help select livestock that are the most efficient, with greater performance and/or carcass yield or quality. Improved beef cattle performance, increased feed efficiency, and increased carcass value are ongoing goals for beef cattle production. For this study, 118 mix breed feedlot calves were genetically tested with The Merial Ltd (Deluth, GA) Igenity GGP Bovine 50K. We compared genotypic and phenotypic average daily gain (ADG), residual feed intake (RFI) and marbling. Igenity scores were not related to ADG in years 1, 2, and 3 (P > 0.14), but were correlated in year 4 (P < 0.01; r = -0.58). Steer RFI displayed no relationship to the Igenity RFI score (P ≥ 0.29). No linear relationships were observed between actual and predicted marbling but did display tendencies to rank animals similar to actual marbling in years 3 and 4 (P ≤ 0.08; P = 0.34, 0.31, respectively). In summary, we did not see a strong relationship between genetic marker predictions and actual performance characteristics. However, relationships appear to be stronger in later years, suggesting more work is needed to validate genetic markers correlation to feedlot performance.