Abstract #369

# 369
Genomic prediction of male fertility in Jersey dairy cattle.
F. M. Rezende*1,2, J. P. Nani1, F. Peñagaricano1, 1University of Florida, Gainesville, FL, 2Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.

Service sire has been recognized as an important factor affecting herd fertility in dairy cattle. Recent studies have reported accurate predictions for Holstein bull fertility using genomic data. This study was conducted to evaluate the feasibility of genomic prediction of sire conception rate (SCR) in US Jersey bulls using alternative predictive models. Data set consisted of 1.5k Jersey bulls with SCR records and 95k SNP spanning the entire genome. Both linear and Gaussian kernel-based models were used either fitting all SNP or subsets of markers with presumed functional roles, such as SNP significantly associated with SCR or SNP located within or close to known genes. The prediction of Jersey SCR records using a multi-breed reference population including the entire US Holstein SCR data set (11.5k bulls) was also investigated. Model predictive ability was evaluated using 5-fold cross-validation with 10 replicates. The entire SNP set exhibited predictive correlations around 0.30. Interestingly, either SNP marginally associated with SCR or genic SNP achieved higher predictive abilities than their counterparts using random sets of SNP. Among alternative SNP subsets, Gaussian kernel models fitting significant SNP achieved the best performance with increases in predictive correlation up to 7% compared with the standard whole-genome approach. Notably, the use of a multi-breed reference population allowed to achieve predictive correlations up to 0.315, gaining 8% in accuracy compared with the standard model fitting a pure Jersey reference set. Overall, our findings indicate that genomic prediction of Jersey bull fertility is feasible. The use of Gaussian kernels fitting markers with relevant roles and the inclusion of Holstein records in the training set seem to be promising alternatives to the standard whole-genome approach. These results have the potential to help the dairy industry improve Jersey sire fertility through accurate genome-guided decisions. Future research should investigate the benefits of using an across-country Jersey reference population.

Key Words: biologically informed model, kernel-based prediction, sire conception rate