The effect of storage on the estrogenic effect of red clover silage

Pure red clover was selected for plant estrogen analyses from the fresh fodder crops of 1972 and 1973. The investigations were made on fresh red clover and on the same red clover after periods of storage of varying length. The red clover was stored in manilla bags in a silo among the ordinary silge fodder, use being of the "green solution method" (Farmos Oy). In the studies the estrogenic effect of the fodder was ascertained by means of bioassay, the criterion being the increase in murine uterine weight. The known plant estrogens were determined by thin layer chromatography and by liquid chromatography. The estrogenic effect of the red clover silage fodder of 1972 was greater in all the silage fodder samples than it was in the fresh red clover. The quantity of individual isoflavones and "transformed" estrogen too, was greater in many of the silage fodder samples than it was in the respective fresh red clover. The estrogenic effect of the silage fodder made from the red clover of 1973 varied considerably; in some samples it was greater but in most it was smaller than the estrogen effect of the fresh red clover. However, apart from a few exceptions, the quantity of individual isoflavones and of transformed estrogens was smaller than it was the fresh red clover.