Validation of Rightmate Precision Mating in Simmental Seedstock Beef Herds Shows Increased Rates of Genetic Progress

This study was designed to validate the rates of genetic progress made in beef herds by implementing RightMate technology. RightMate leverages previously identified large effect genes, genomic relationships amongst selection candidates, current National Cattle Evaluation Expected Progeny Differences (EPDs), and MateSel software to meet producer defined breeding objectives. This study utilized three Simmental herds, two with over 350 head of calves born per year (Herd A, n = 11,185; Herd B, n = 3,127) and one with under 300 calves born per year (Herd C, n = 3,299). Each herd had five or more years of calves produced under the RightMate mating strategy and at least seven years of calves produced under traditional mating strategies prior to RightMate included in these analyses. A model with indexes and EPDs as dependent variables and RightMate implementation as a fixed effect and year of birth nested within RightMate or non-RightMate mating systems fit as independent variables was fit in JMP software. In all three herds birth year of calf nested within RightMate mating systems was significant for: All Purpose Index (API), Terminal Index (TI), Calving Ease, Birth Weight, Weaning Weight, Yearling Weight, Average Daily Gain, Maternal Calving Ease, Maternal Milk, Stayability, Carcass Weight, Marbling, and Ribeye Area EPDs (P < 0.0001 for all). Annual progress in years when RightMate was implemented to assign matings was 66% to 183% higher than non-RightMate annual progress for API and 27% to 204% higher for TI across herds. We also evaluated the incidence of extreme actual birth weights (<27.2 kg or > 43.1 kg) with a logistic regression model with RightMate mating system as a fixed effect and year of birth as a random effect. The calves born out of the RightMate mating systems had lower incidence of extreme birth weights in Herd A (P < 0.001) and Herd C (P = 0.01) but not in Herd B (P = 0.30). This outcome may have been related to philosophical approach of Herd B management rather than effectiveness of the RightMate tool. Futhermore, these herds had implemented RightMate breeding for long enough that we could initiate characterization of the effect of dams in the herd being the product of RightMate matings or not and their calves being the product of RightMate matings or not in a 2 x 2 factorial design. To no surprise, the dams being out of RightMate matings and the calves being out of RightMate matings were cumulative in the performance of progeny EPDs. Across all three herds studied there were benefits of dams and calves being the result of RightMate matings for API, TI, and Marbling EPDs. Also, in two herds there were benefits of dams and calves being the result of RightMate matings for Birth Weight and Maternal Calving Ease EPDs.