Scientists have released a first draft of the bovine genome - a run through of the genetic code that describes a cow.
Dominette with her calf
A fuller version will follow in 2005 but already researchers can use the data to compare bovine genes with those from humans and other animals.
This is likely to aid our understanding of human genetics and disease, as well as improving the health and well being of cattle themselves.
Scientists believe the work will also lead to better beef and dairy products.
The genome of the cow (Bos taurus) is being produced by an international team led by Dr Richard Gibbs, from Baylor College of Medicine's Human Genome Sequencing Center in Houston, Texas, US.
The researchers are using samples from a Hereford cow, named L1 Dominette 01449, for the bulk of their sequence work.
COW DNA - BOS TAURUS
The double-stranded DNA molecule is held together by four chemical components called bases
Adenine (A) bonds with thymine (T); cytosine(C) bonds with guanine (G)
Groupings of these letters form the "code of life"; there are estimated to be about three billion base-pairs in the cow genome wound into 31distinct bundles, or chromosomes
Written in the DNA are possibly 30,000 genes which cow cells use as starting templates to make proteins; these sophisticated molecules build and maintain the animal's body
This animal is used in beef production. Investigations of the genetics of other breeds - including the Holstein, Angus, Jersey, Limousin, Norwegian Red and Brahman - are also being conducted to get a broader picture of the important genetic factors that control good meat and milk production.
The bovine genome is similar in size to the genomes of humans and other mammals, containing approximately three billion DNA base-pairs. Like the other mammals already sequenced, or in the process of being sequenced, it is expected to have about 30,000 genes.
So far, the international team has, broadly speaking, read through the cow's DNA complement 3.3 times.
By early next year, the scientists will have been through it six times. This should ensure there are no gaps in the sequence, and any mistakes have been corrected.
All the information from the $53m project is being deposited into free public databases for use by biomedical and agricultural researchers around the globe.
They can use web tools such as the Ensembl Genome Browser at the Wellcome Trust Sanger Institute in Cambridge, UK, to mine the data.
Dr Tim Hubbard, who heads up the Human Genome Analysis group at the Sanger, says the cow is part of a broad strategy to decode a range of animals.
Cows are interesting because traits have been inbred
And comparisons between them should make it easier to understand our own biochemistry.
"From the point of view of them being models, the dog and the cow are interesting because they have been inbred for a long time," he told BBC News.
"If you think about the variation in the height of the dog or the variation in milk yields in cows or other factors - the point is you can relate those things which have been bred against the genes underneath. You can use it to understand the relationships you've inbred."
"The cow is a good model because of this long history of human breeding."