How much of a dairy goat’s observed traits is a result of the animal’s genetics? How much is an environmental influence?

Breeders could more accurately evaluate a dairy goat’s merit if they had clearer answers to these questions.

Now, researchers at the Agricultural Research Service have devised a mathematical formula that will help. The formula describes genetic as well as environmental components of traits such as a goat’s strength, stature and udder shape. It separates temporary environmental factors, such as the season, from permanent ones such as injury.

The formula also considers influences of all of the animal’s relatives--not just its sire, as other models do.

The researchers found that the least likely genetic influences are rear udder arch and rear legs. By contrast, stature, teat diameter and placement are highly heritable.

The formula was developed with data from the American Dairy Goat Association, including records of 154 herds and six breeds, and pedigrees for animals born in 1978 or later.

Scientific contact: Suzanne Hubbard and George Wiggans, USDA-ARS Animal Improvement Programs Laboratory, Beltsville, Md., phone (301)504-8334