Archives West Finding Aid

Diary Herd Improvement Associations, commonly called DHIAs, were first formed in the state of Washington in 1916, facilitated by the agricultural extension service.

The idea of a DHIA is keeping records of concerning milk production of dairy cows, tracking individual animals. A group of dairy farmers form an organization, subscribe to the service, employ a party called a tester, and support a small laboratory. Once or twice a month, the farmers weigh the milk produced by individual animals and collect small samples.. The tester conducts lab operations to determine the content of milk fat and other solids, and also assembles the numeric information and provides periodic reports. These "herd book" reports can be ordered so as to list the production of each animal, ranked from highest to lowest. This information guides the farm operator in the selection of which animals to cull and which to use as the parent stock. The process tends to select a high-producing strain. Over time the overall average production level should rise. Since 1916, production per cow has risen dramatically, five- or six-fold.

A DHIA report can also be used for other management purposes, of course.