An investigation was carried out to detect and evaluate the oestrogenic activity of three successive cuts of Egyptian clover berseem (Tifolium alexandrinum). Changes in oestrogenic activity due to wilting, drying and fermentation were also studied.
Oestrogenic activity was higher (P < 0·01) in first-cut berseem (49–6 ug diethylstilbestrol equivalency (DES)/kg D.M.) than in the second (38·2 ug) and the third cuts (36·1 ug), and was decreased in the three successive cuts by wilting and dehydrating to 88% D.M. It was greater (P < 0·01) in the wilted berseem than the dried material of the second cut. Oestrogenic activity was increased (P < 0·05) in all cuts by fermentation, but it was higher (P < 0·01) in the fermented second cut than the other cuts.
An intake of 10 kg D.M. of silage would be equivalent to 0·98 mg DES, which have no adverse effects on production and reproduction.