ON FARM SHEEP FEEDBASE f l How well do you knowi i i i your paddocks?es raiith r cl at li tc?igl ro i Recent sur conduct i t i to igh rinfll znes f ther t lia f tha ol • ost co ol , Tihreasd ry e cet e Keep your head down whenf slover rterraneanu i Scolving a historical problemi e researchers trekked through you’re out in the pad dockc rs taiInthe early 1970s, it was found thathil lhundreds of paddocks across southernbi this winter.coi unds ich manyof the sub-clover cultivars plantedac orry liAustralia identifying oestrogenic cloversi rtili sheep lt. widely across southern• Aus itralia in the(see story page 26).r lapse That’s the tip from The University first half of the 20th century contained of Westiertn Australia (UWA) Senior high levels of an oestrogenic compound,• irease in e“It’s probably the best Research Officer Dr Kevin Foster, who formononetin,, rintheir green leaves.reinsnapshot of our sub‑cloverilk now isi rpr health le • said a good time to really get to retio in ai and et s, flse ladder knowand igh level ic co pastures out there that your paddocks.o oest The release of new, low-fion rmononetins ‘ loetver di f onetin, i l cl ’. cultivarsin the late 1970s was thought we’ve had for many, many i , l br ing rhave resolved the issue.to a it i l y ea sr ts i clti distinguishing features in the leavseesd ltivar i ,” Dr Foster s aid . of subterranean clover (sub-clover), ti . cHowever, the hard-seeded nature ofi a a o makinpgr it elasi er to tidentify cultivars – l rgloestrogenic cultivars has seen a gradualr ih tr cl iInr sanalysing hundreds of plant samples,be ry ifsitent. including the old oestrogenic cultivalrse declinedresurgence of the issue in recent years.t ren 25the rrsesearchers found around 20%no doinat, the whichknoledgecan negatively affect sheep ingre Inresponse, MLA Donor Companyiat hi ly past eseven inclof pastures in southern Australiat , . healthand reproduction rates.i ini . supported a project (led by Dr Foster are dominated by high-oestrogen With decent autumn rains across much andhis UWA colleague Megan Ryan)i t prsub-clover, with some districts havingc f i l of southern Australia, Dr Foster warns to provide producers and advisors with cla figure of higher than 65%. r r an early break could mean higher intake information and skills toIf identify andthey ribteThe most common oestrogenic cloverbif tur r ore ass. of oestrogenic clovers and an adverse manage the presence of oestrogenic found in the pasture samples submitted impact on flock fertility. sub-clover. so far has been Dinninup. Which cultivars are high Dwalganup Geraldton in oestrogens? Slight Red Dwalganup, Geraldton, Dinninup pink calyx and Yarloop are most likely to calyx contribute high levels of oestrogens in pastures. Tallarook is present only in districts with very high rainfall. Some locally evolved sub-clover variants are also highly oestrogenic, Leaf – crescent with white arms, leaf Leaf – narrow, triangular, distinctly including Eden Valley in SA and often has fold, brown flush in winter.spaced leaflets, band leaf mark Book Book in NSW. Hairy runner. Early flowering. and often brown flush midrib. Hairy runner. Early flowering. Dinninup Yarloop Tallarook Red calyx Green on calyx half to 1/4 Green tube tube calyx Leaf – full crescent with distinctive Leaf – no crescent only white Leaf – crescent with white arms flush pattern and thin line arms, brown flush midrib. Hairless which fade in spring, often brown surrounding leaf mark. Hairy runner. runner. Late flowering. Adapted to flush below the leaf mark in winter. Late flowering. waterlogging. Cream/amber seed. Hairy runner. Very late flowering. 24