A common reference population from four European Holstein populations increases reliability of genomic predictions

Table 1 Validation of parent index (PI) and genomic breeding values (GBV) using Nordic (DSF_ref) and EuroGenomic (EU_ref) reference populations

Trait	Number of bulls			Nordic reference				EuroGenomic reference
	DFS_ref	EU_ref	valid	REL_PI	b₀	b₁	REL_GBV-PI	REL_PI	b₀	b₁	REL_GBV-PI
Protein yield	3038	10701	942	0.21	2.63	0.82	0.19	0.22	1.98	0.86	0.32
Udder depth	2958	10755	948	0.12	2.80	0.98	0.29	0.13	1.70	0.90	0.42
SCS	3077	10880	947	0.21	1.27	0.99	0.19	0.22	0.44	0.94	0.32
NRR	3069	10712	942	0.29	-0.71	1.08	0.14	0.29	-1.02	0.98	0.19
Average	3035	10762	944	0.21	1.50	0.97	0.20	0.22	0.78	0.92	0.31

REL_PI: r²_{(PI, DRP)}/REL_DRP, DRP is deregressed proofs in the validation dataset, REL_DRP is the average reliability of DRP; REL_GBV-PI: the difference between REL_GBV and REL_PI, where REL_GBV is r²_{(GBV, DRP)}/REL_(DRP); b₀ is intercept and b₁ is regression coefficient of DRP on GBV

ISSN: 1297-9686