Estrogenic Activity of Fresh and Dried Red and Subterranean Clovers1

Abstract
Red clover and 3 varieties of subterranean clover (Dwalganup, Tallarook, and Mt. Barker), planted in June, 1958, at Albany, California, were periodically assayed for estrogenic activity over a 6-month growing period. The potency of the subclovers reached a maximum between 3 and 4 months after planting, remaining high for the duration of the study, although there were some fluctuations with time as well as between varieties. Although not as active as the subterranean clovers, red clover nevertheless maintained a relatively high activity throughout the growing period of this study. Peak activity was reached at 2 months and again at 5 months after planting. Drying of the clover prior to assay resulted in little if any reduction in estrogenic activity. In fact, several of the dried forage samples contained more estrogenic activity than did the comparable fresh material.