Ideas for continuous genomic evaluation for newly genotyped Walloon Holstein females and males

Crucial for large scale use in dairy cattle of genotyping for females is that any newly genotyped animal (calves, cows and heifers but also bulls) receives very quickly genomic breeding values (GEBV) even outside the official schedule for routine evaluations. In this study, a system was developed to estimate initial GEBV for newly genotyped animals before their inclusion in the official routine release of genomic evaluations. The system was setup to be run on request, featuring the setup of a ‘continuous’ evaluation, also being quick and simple enough to be used at least on a weekly base. For animals without own records or descendants, official GEBV were approximated using selection-index like method by combining direct genomic values (DGV) of newly genotyped animals and their parent average (PA). DGV for new genotyped animals were calculated based on SNP effects from the previous official routine evaluations (April and August, 2017). Depending on GEBV accessibility from parents of a given animal, PA was calculated based on conventional phenotypic information (cPA), and parent GEBV (gPA). To expand the system for animals with progeny, a subset of genotyped animals was selected, and conventional estimated breeding values (cEBV) and cPA of selected animals were combined with DGV and gPA in order to obtain GEBV for animals with progeny. The weights were calculated based on the covariance between DGV and gPA for animals without progeny, and between DGV, gPA, cEBV and cPA for animals with progeny. Correlations between initial and April official evaluations for 60 new genotyped animals without progeny varied from 0.87 to 0.95 for conformation, fertility and production traits, whereas correlations between initial and August official evaluations varied 0.84 to 0.92 (n=25 new genotyped animals). On the other hand, correlations between initial and August official evaluations for 120 genotyped animals with progeny varied from 0.95 to 0.97 for production traits. Study showed potential to use simple selection index based methods in continuous genomic evaluations, a way to support genotyping of females for genomic selection but also for management and marketing.