Bovine genome: The genome of the cow (Bos taurus). The bovine genome is similar in size to the genomes of humans and other mammals, containing approximately 3 billion DNA base pairs. The breed of cattle selected for initial sequencing was Hereford, which is used in beef production. Sequencing began in December 2003 and a first draft was completed in October 2004. Sequencing of additional cattle breeds, including the Holstein, Angus, Jersey, Limousin, Norwegian Red and Brahman, allows tracking of the DNA differences between these breeds to assist in the discovery of traits for better meat and milk production and, as with all non-human genomes, to model human disease.