Journal of the Department of Agriculture, Western Australia, Series 4


Medicago, Phosphorus fertilizers, Coumestrol, Plant oestrogens

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Western Australia has a million acres of medics including various cultivars of barrel medic, Medicago truncatula, and strand medic, M. littoralis. Both species contain coumestrol, a chemical thought to have caused delayed conception and reduced twinning rates among grazing ewes in New Zealand.

No infertility has been reported among ewes grazing medic pastures in Western Australia, but coumestrol levels in both species have often been high enough to suggest the possibility of oestrogenic responses among sheep grazing them.