Life Sciences Commons^™

Clover Infertility Of Sheep : Continuing Problem, N R. Adams, Keith Croker

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

Some varieties of subterranean clover, notably Dinninup, Dwalganup and Yarloop, contain compounds which act like the female sex hormone oestrogen. These plant oestrogens, or "phyto-oestrogens", interfere with the fertility of sheep and depress the percentage of lambs born.

Over the past 10 years our understanding of clover infertility has increased, and we can now gauge the extent of this residual problem. In fact, there is a widespread but low-level incidence of infertility which does not greatly affect individial farms but which has an important impact on the State's sheep production.

Clover Disease : What Do We Know And What Can We Do, T Marshall

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

A review of 30 years' study and practical experience of clover disease in Western Australia—and a summary of current recommendations for reducing problems in sheep grazing pastures based on oestrogenic subterranean clover.

Pasture Legume Varieties And Ewe Fertility, T Marshall, H. E. Fels, H. G. Neil, R. C. Rossiter

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

ALTHOUGH it was first thought that all varieties of subterranean clover would cause ewe infertility, research in the last 10 to 15 years has shown that varieties differ in potency.

The relative level of potency has also been shown to remain consistent for any one variety under normal conditions.

Phosphate Applications Affect The Coumestrol Level Of Medics, T Marshall, R. J. Parkin

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

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.

Control Of Clover Infertility In Sheep, H G. Neil, H. E. Fels, C. M. Francis

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

A summary of practices recommended for the control of infertility caused by subterranean clover in West Australian sheep.

PROLONGED grazing of green subterranean clover pastures often reduces ewe fertility. In more extreme cases, obvious signs of clover disease occur.