Coumestans in lucerne and ovulation in ewes

  title={Coumestans in lucerne and ovulation in ewes},
  author={J. Smith and K. T. Jagusch and L. F. C. Brunswick and R. W. Kelly},
  journal={New Zealand Journal of Agricultural Research},
Abstract Four trials with a total of 1750 Perendale ewes were conducted to determine the effect of feeding lucerne on ovulation rate and lambing performance. Levels of up to 600 ppm coumestans in lucerne leaf, associated with fungal infection, depressed ovnlation rate and lambing by 34% and 14.6% respectively. In the absence of fungal infestation no coumestans were found and stage of regrowth had 110 effect on lambing performance. A negative linear relationship between coumestan ccntent of the… 

Recovery of ovulation rate in ewes following their removal from an oestrogenic lucerne forage

This experiment quantified the decrease in risk of impaired lambing performance due to moderately oestrogenic lucerne consumption in relation to time on grass before ovulation and found that removal of ewes fromLucerne 2 weeks before Ovulation mitigated the risk of decreased lambingperformance.

Causes of elevated coumestrol in lucerne and mitigation of the subsequent risk to ewe reproductive performance

This thesis isolated the factors with potential to increase the coumestrol levels of lucerne and enabled management strategies to be developed to mitigate the risk of depressed ovulation rate in ewes grazingLucerne during the mating season.

Alfalfa Coumestrol Content in Response to Development Stage, Fungi, Aphids, and Cultivar

Identifying when and why coumestrol levels are elevated is a key requirement to refine alfalfa grazing management to reduce potential benefits of increased ovulation gained from increased ewe liveweight in dry summer and/or fall periods.

Reproductive performance of Coopworth ewes following oral doses of zearalenone before and after mating.

The results indicate that the effects of zearalenone, administered orally, on ewe reproduction, at the dose levels examined, were restricted to ewes exposed before mating.

The effect of grazing ewe lambs on lucerne (Medicago sativa) prior to breeding on aspects of reproductive performance

The hypothesis was that offering lucerne for a one-month period that ended 14 days prior to breeding would alter the pattern of breeding and pregnancy and reproductive rates of ewe lambs.

Short-term grazing of lucerne and chicory increases ovulation rate in synchronised Merino ewes.

Permanent infertility in ewes exposed to plant oestrogens.

  • N. Adams
  • Biology, Medicine
    Australian veterinary journal
  • 1990
In Australia, more than 1 million ewes have permanently damaged reproductive tracts because they have been grazed on oestrogenic pasture, and further progress with the present problem may depend on the development of animal-based solutions.

Effects of oestradiol implants on the ovulation rate of the ewe.

The hypothesis that oestrogen is involved in the physiological control of ovulation rate in the ewe is supported, but this action is probably not restricted to the assertion of dominance by a maturing follicle during the follicular phase.



Effect of coumestans on reproduction in the ewe

It was suggested that coumestans inhibit oestrus through inhibiting the production of endogenous oestrogen.

Change with length of feeding period in the oestrogenic response to ovariectomized ewes to ingested coumestans

The decline in the cervical mucus response suggested either that a deactivation mechanism for coumestans develops in the ewe, or that the ewes becomes refractory to coumstans.

The plant estrogen, coumestrol, as an agent affecting hypophysial gonadotropic function.

The results of this study indicate that coumestrol has physiological effects on hypophysial function, relatively large doses are required for antigonadotropic effects, and its primary effect on gonadotropes is to inhibit release.

Wether bioassay of annual pasture legumes. IV. The oestrogenic activity of annual medic pastures

The oestrogenic activity of seven medic pastures measured at the time of flowering , by wether bioassay was highly correlated with their coumestrol content. The most active varieties M. littoralis

Influence of Controlled Environmental Factors and Two Foliar Pathogens on Coumestrol in Alfalfa1

IT HAS long been known that estrogenic substances occur in forage plants and that their occurrence may affect animal performance As early as 1946 sheep infertility was associated with estrogenic

The reproductive performance of ewes mated on lucerne.

Tests were conducted to make a comparison between the reproductive performances of ewes de-pastured during mating on lucerne and on rye-grass-white clover, which was grown on thinner soils than was the pasture.

Varietal variation in the isoflavone content of subterranean clover: Its estimation by a microtechnique

The isoflavone content of 46 subterranean clover varieties was estimated by a microtechnique which allowed of the semiquantitative analysis of 100 leaf samples per day. The relative proportions of

The oestrogenic activity of white clover (Trifolium repens L.)

Abstract Oestrogenic activity in samples of diseased white clover has been demonstrated in mice and sheep. Relative potencies were found to parallel, in general, concentrations of coumestan compounds.