For more than half a century, progeny testing has been the foundation of genetic selection programs in dairy cattle, and it has led to rapid genetic gains in traits such as milk production, for which breeding values of bulls and cows have increased by roughly 200 pounds per year. However, progeny testing is expensive and time-consuming due to a long generation interval in cattle, and it is not an effective method for improving traits that are difficult or expensive to measure routinely on commercial dairy farms, such as feed efficiency. Whole genome selection, more commonly known as genomic selection, refers to using information about single nucleotide polymorphisms (SNP) markers in the cattle genome to predict the genetic merit of young animals that have no offspring or performance data at the time selection decisions are made. The information obtained by genomic testing a young heifer or bull is compared with genomic data from a reference population of older animals of the same breed. The Council on Dairy Cattle Breeding (CDCB) provides routine genomic predicted transmitting abilities (PTA) for US dairy cattle, and more than 800,000 dairy bulls, cows, heifers, and calves have been tested to date. Genome-Tested Young Sires Virtually every bull offered to US dairy farmers has been chosen based on the results of genomic
At the 2015 Western Dairy Management Conference, UW-Extension Dairy Scientist Kent Weigel discusses the use of genomics in sire selection. For more information on his presentation, please visit Effective Use of Genomics in Sire Selection & Replacement Heifer Management.