The issue with oestrogenic sub clover pastures

What is the problem?

Recent surveys conducted in the medium to high rainfall zones of southern Australia have found that old cultivars of subterranean clover remain common in many pastures. Some of these cultivars contain high levels of oestrogenic compounds which can negatively impact sheep health.

History

The link between sheep reproductive health problems and high levels of the oestrogenic compound, formononetin, in the leaves of sub clover was first made in the 1960s. In response, plant breeding programs quickly developed and released new cultivars with lower, safer, levels of formononetin. By the 1980s, the problem was thought to have been largely resolved. Communication about the problem declined and knowledge on how to identify and remediate highly oestrogenic pastures diminished.