Metabolism of estrogenic isoflavones in domestic animals.

The metabolism of estrogenic isoflavones in cattle and sheep is reviewed. Results from in vitro and in vivo studies are discussed, mainly regarding whether differences in sensitivity to phytoestrogens between cattle and sheep depend on differences in metabolism, particularly in conjugative capacity. Results from a feeding experiment with pigs fed red clover meal are presented. Levels of phytoestrogens in plasma from the pig are compared with those found in plasma from ruminants fed red clover silage. Some aspects relating to the possibility of pigs being exposed to risks when fed with feed containing estrogenic isoflavones are briefly discussed.