Observations on the Effect of Drying on Estrogenic Activity of Alfalfa Samples of Varying Maturity

Abstract

The estrogenic activity of alfalfa was compared at different stages of maturity in five crops cut during 1958 and in the spring growth (first crop) of the 1959 season. Estrogen content followed a fairly similar pattern in all of the crops. The estrogen content was quite low in the vegetative stages and then increased gradually as the plant matured, usually reaching its highest level at about the full bloom or seedhead stages. The third crop attained its peak activity in the early bud stage and remained high throughout the life cycle of the plant. The winter growth attained high levels of activity without ever blossoming. The 1959 crop never attained more than one-third of the peak activity of the comparable 1958 crop. Drying fresh forage samples prior to assay sometimes leads to significant losses of apparent estrogen activity. The amount of loss varied considerably in different samples, ranging from no loss in some cases, to more than 75% in others. It is recommended that fresh forage samples be assayed without prior drying. Copyright © . .