Application of Genomic Selection in the New Zealand Dairy Cattle Industry

The New Zealand (NZ) dairy industry has used genomic information to enhance its genetic evaluations for the last 13 years. The first 10 years provided little benefit to farmers and breeding companies. Sequencing of the bovine genome in 2006 generated a pool of SNPs that have been commercialised and subsequently used by the bovine research community. The improvement of the accuracy obtained by including genomic information on thousands of animals in the national evaluation system is sufficient to predict that NZ’s dairy breeding programme will be revolutionised by genomic technology. The genomically-enhanced breeding (GEBVs) of one-year-old bulls are more reliable than BVs based on parent average, thus allowing them to be reliably selected and used in the national herd. Traditionally, use of young bulls was limited and bulls were not used extensively until they were five years old when the more reliable progeny test results became available. Using young sires, as opposed to progeny-tested sires, in the breeding programme dramatically reduces the generation interval, thereby increasing the rate of genetic gain by 40%-50%. Young sires haven been marketed on their GEBVs in NZ for the last four years. Initial results have shown that the genomic estimates were over-estimated. Adjustments have been introduced into the national evaluation to reduce the bias. Statistical tool development, genotype exchanges and genotyping of cows have been undertaken to increase the accuracy and reduce the bias of the genomic predictions. In addition, sequencing of the dairy cattle population has just commenced in an effort to further improve the genomic predictions and also to detect causative mutations that underlie traits of economic performance.