HOW to identify and remediate subterranean clover pastures that cause sheep infertility is the focus of a new ute guide co-created by researchers from The University of Western Australia (UWA).
The Oestrogenic Subterranean Clover Guide is a collaboration between the UWA Institute of Agriculture, the Department of Primary Industries and Regional Development (DPIRD), and the Meat & Livestock Australia (MLA) Donor Company as part of the project 'Maximising the reproductive potential of the meat sheep industry by eliminating high oestrogen clovers'.
Subterranean clover is the most widely grown pasture legume in southern Australia, however livestock producers are often unaware that some outdated cultivars can contain high levels of the phytoestrogen formononetin - a compound that causes fertility issues in sheep.
As new cultivars have been selected for low formononetin, DPIRD research scientist and UWA Institute of Agriculture honorary research fellow Kevin Foster said many producers assumed the problem was resolved.
"Unfortunately, oestrogenic cultivars can be very persistent and may be hidden within older permanent pastures or have contaminated newly-sown pastures where they are difficult to distinguish from newer cultivars," Dr Foster said.
He said there were several sheep fertility and health issues that could occur from grazing oestrogenic clovers, such as an increase in dry ewes at scanning or reduced lambing percentages.
"That link has been largely forgotten by the farming community and the resulting fertility issues may be misdiagnosed," Dr Foster said.
Professor Megan Ryan and senior research officer Daniel Kidd from the UWA School of Agriculture and Environment and the UWA Institute of Agriculture co-authored the publication.
Mr Kidd said the ute guide would help producers accurately and efficiently identify oestrogenic subclover cultivars under field conditions.
"To aid with cultivar identification, it provides detailed descriptions of leaf, stem and flower morphology for each oestrogenic cultivar," Mr Kidd said.
Additionally, the guide will show users how to assess the abundance of oestrogenic clovers in their pastures.
"If abundant, the guide can help them to decide whether to manage the problem or to remove the clovers through effective pasture renovation," professor Ryan said.
"It also aids readers to identify the effects of oestrogenic clover on sheep fertility."
MLA Donor Company program manager Joe Gebbels said he was delighted to see the launch of the ute guide.
"This user-friendly tool will for the first time enable producers to identify and manage this important issue," Mr Gebbels said.
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