Determination of Estrogenic Activity in Fresh and Dried Forage

Abstract

Since it has been found that dehydration lowers the apparent estrogenic activity of a forage, different techniques have been developed for preparation of extracts for bioassay. Freshly harvested forage is rapidly macerated in a mechanical blender with acetone in order to extract the estrogens. The dried samples are Soxhlet extracted with acetone for 24 hours. In either case the acetone extract is incorporated into the control diet and the solvent removed. Estrogenic activity is evaluated by feeding the test diets to immature female mice and determining the increase in weight of the freshly excised uteri.