Abstract

Formononetin is the major red clover phytoestrogen responsible for reproductive dysfunction in sheep. Formononetin is metabolised in the rumen to equol which is significantly more oestrogenic. This study was conducted to characterise the accumulation of conjugated and free equol in the blood of ewes grazed on either high formononetin (cv Pawera, 0.57% of dry matter) or low formononetin (cv G27, 0.25% of dry matter) red clovers over a 1, 2 or 3 week period and the subsequent clearance of equol after removal from the red clover. Seventy mixed age ewes were divided into 7 treatment groups (n=10). Each group grazed either Pawera or G27 red clover for 3, 2 or 1 week or ryegrass (control group) prior to mating as one flock on ryegrass pasture. All ewes were regularly blood sampled. Once mated, the ewes were laparoscoped and returns to service recorded. Conjugated equol concentrations in both Pawera and G27 ewes increased over the first 2 days to 23.97

R, Kramer, RG Keogh, and MF McDonald

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 373-377, 1996