ON FARM SHEEP What’s the damage? Think you might have a Consumption of older cultivars – sub-cloverroblem?p RESEARCH IN Dinninup, Dwalganup, Yarloop, If producers suspect they have problem REVIEW Geraldton and Tallarook – can lead to sub-clover, the first step is to get two forms of infertility in ewes. One is confirmation. PROJECT AIM short-term, with a return of fertility after Seek expert advice and support from To identify the ongoing impact of removal from the high-oestrogenic your local agronomist or vet, or talk to old subterranean clover pastures pastures, and the other is permanent an agricultural department staff member with oestrogenic qualities on infertility which increases in severity in your district to help identify cultivars. Australia’s sheep production and to with continued exposure. work with producers and advisors Permanent infertility can also be After confirming the presence of to identify and manage the impact. accompanied by ewe mortality, difficult high-oestrogenic sub-clovers, work with your advisors to establish a RESEARCH ORGANISATIONS births and post-natal lamb mortality. management plan. The University of Western Even lambs dropped onto oestrogenic Australia and the Department of pastures may be infertile as maidens. “When prices and demand are strong, it’s Primary Industries and Regional It can also cause udder development a good time to allocate funds to invest Development, WA problems in maiden ewes and urethral in improving your pastures, particularly blockages in wethers. those which aren’t supporting your FUNDING ORGANISATIONS animal enterprise productivity as best The UWA Institute of Agriculture Before this research, many producers they could,” Dr Foster said. ■ through the UWA Future Farm and and agronomists were not aware of MLA Donor Company high-oestrogen cultivars, so poor reproductive performance was often Samples of sub‑clover can still be DURATION attributed to other husbandry problems. submitted for testing as part of this June 2018 – August 2021 project. Contact Dr Foster for a “When you see the light-bulb moment testing kit, but be quick, as there KEY FINDINGS TO DATE that happens when producers realise are limited test kits available • Oestrogenic sub-clovers were they have a problem with their for 2020. found to dominate more than 20% sub-clover, which could’ve been Dr Kevin Foster of sub-clover pastures sampled. causing a whole lot of challenges they The University of Western Australia • In many cases, producers, haven’t been able to get to the bottom E: kevin.foster@uwa.edu.au advisors and government of until now, it makes you realise this departments were unaware has been such a great investment in Oestrogenic sub‑clover pastures of the presence and impact of research, development and extension,” fact sheet oestrogenic sub-clovers. Dr Foster said. mla.com.au/ sub‑clover‑identification • Consumption of oestrogenic “Our research suggests we need to sub-clovers is likely a significant rule out if it’s what ewes are eating in Unleash your sub‑clover’s cause of reproductive wastage the pasture that’s the actual reason super powers in sheep, particularly Merinos. for dry ewes.” mla.com.au/sub‑clover Two ways to manage problem clovers If you have problem clovers in your paddocks, there are two management options. 1. Avoid grazing the paddock with nutrition up to the sub-clover, as Tip:Hay or silage made from young ewes or lambs and limit formononetin in the green leaves green, high-oestrogenic clover is grazing by wethers (rams are not can increase when clover growth likely still potent, but sub-clovers thought to be affected). Don’t is limited. can be safely grazed when they ‘grass clean’ pastures, as dilution 2. Go for the ultimate solution dry naturally at the end of the is part of the solution. Oestrogenic and renovate pasture with a season. However, ewes should not clovers need to be less than 20% low-formononetin sub-clover start grazing until six weeks after of overall pasture to avoid livestock cultivar suitable for your district. drying starts. health issues. New cultivars also have other Help livestock avoid the improved traits to enhance oestrogenic pastures when green productivity. This is also a good by providing other feed sources opportunity to improve soil or using other paddocks. Keep fertility and rhizobia for long-term soil phosphorus and sulphur productivity gains. ■ 25