
%0 Journal Article
%A Kaltenbach, cC 
%A Davies, HL 
%T Fertilization, sperm transport, and early embryonic loss in ewes grazed on cultivars of subterranean clover. (<I>T. subterraneum</I>)
%J Australian Journal of Agricultural Research
%D 1970/02/01
%V 21
%N 1
%P 107-114
%K 
%R https://doi.org/10.1071/AR9700107
%U https://www.publish.csiro.au/paper/AR9700107 
%X The causes of infertility due to phyto-oestrogens were investigated in ewes which had grazed Dwalganup, Yarloop, Geraldton, Woogenellup, and Mount Barker cultivars of subterranean clover (T. subterraneum L.) for 5 years. At laparotomy, sperm transport was investigated by making counts of spermatozoa in the oviduct 22-26 hr post coitum; fertilization rates were checked 72 hr post coitum and embryonic survival at 27-31 days. A larger proportion of ewes on high oestrogen cultivars Dwalganup, Yarloop, and Geraldton) had low oviducal spermatozoa counts and the fertilization rate was significantly lower (P < 0.05) than in ewes grazed on low oestrogen cultivars (Woogenellup and Mount Barker) (44% v. 63 %). There was no statistically significant difference in embryonic survival between these groups. Merino ewes had fewer oviducal spermatozoa and a lower (P < 0.05) fertilization rate than Border Leicester x Merino ewes. Impaired sperm transport is considered to be the reason for reproductive failure in the ewes that had grazed the high oestrogen cultivars of subterranean clover. 
