The reproductive performance of ewes mated on lucerne

Coop, I. E.; Clark, V. R.

doi:10.1080/00288233.1960.10419307

Cited by 20 publications

(12 citation statements)

References 6 publications

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“…Ovulation rate was linearly related to dietary coumestrol content over the range 0 to 100 mg/kg; the number of ovulations fell from 1.44 to 0.98; ewes with high ovulation rates were more sensitive to coumestans [51]. Coop and Clark (1960) [128] reported that ewes mated on lucerne recorded a 10-12% decrease in lambing, mainly due to a reduced number of twins. Coop (1977) [26] suggested the decrease was likely to be greater in high fecundity breeds (Table 3).…”

Section: Ovulationmentioning

confidence: 99%

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Fertility of Herbivores Consuming Phytoestrogen-containing Medicago and Trifolium Species

Reed¹

2016

Agriculture

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Despite their unrivalled value in livestock systems, certain temperate, pasture, legume species and varieties may contain phytoestrogens which can lower flock/herd fertility. Such compounds, whose chemical structure and biological activity resembles that of estradiol-17α, include the isoflavones that have caused devastating effects (some of them permanent) on the fertility of many Australian sheep flocks. While the persistence of old 'oestrogenic' ecotypes of subterranean clover (Trifolium subterraneum) in pasture remains a risk, genetic improvement has been most effective in lowering isoflavone production in Trifolium species; infertility due to 'clover disease' has been greatly reduced. Coumestans, which can be produced in Medicago species responding to stress, remain a potential risk in cultivars susceptible to, for example, foliar diseases. In the field, coumestrol is often not detected in healthy vegetative Medicago species. Wide variation in its concentration is influenced by environmental factors and stage of growth. Biotic stress is the most studied environmental factor and, in lucerne/alfalfa (Medicago sativa), it is the major determinant of oestrogenicity. Concentrations up to 90 mg coumestrol/kg (all concentrations expressed as DM) have been recorded for lucerne damaged by aphids and up to 600 mg/kg for lucerne stressed by foliar disease(s). Other significant coumestans, e.g., 4'-methoxy-coumestrol, are usually present at the same time. Concentrations exceeding 2000 mg coumestrol/kg have been recorded in diseased, annual species of Medicago. Oestrogenicity of some Medicago species is also influenced by maturity and senescence. Studies in Israel, North America, Europe, New Zealand and Australia have confirmed that coumestans in lucerne, represent an acute or sub-acute loss of reproductive efficiency in herbivores, e.g., sheep, cattle, and possibly horses. When sufficiently exposed peri-conception, coumestrol, sometimes present in lucerne, be it as pasture, hay, silage, pellets, meal, and sprouts, is associated with what can be an insidious, asymptomatic, infertility syndrome. Most livestock research with oestrogenic lucerne has been conducted with sheep. Ewes may be at risk when the coumestrol concentration in their diet exceeds 25 mg/kg. In studies where lambing was compared for lucerne and a phytoestrogen-free treatment, the mean decrease in lambs born/ewe was 13%; ewes on lucerne, exhibited a lower frequency of multiple births.

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Section: Ovulationmentioning

confidence: 99%

“…Five months into pregnancy, the verified abortion rate was >10% in premiparous ewes and 5% in adult ewes [99]. In the seven studies where lambing was observed for lucerne compared with an oestrogen-free treatment [26,27,91,128,129] (Table 3), 13.4% less lambs were born to ewes on lucerne (range 0% to 32%).…”

Section: Ovulationmentioning

confidence: 99%

Fertility of Herbivores Consuming Phytoestrogen-containing Medicago and Trifolium Species

Reed¹

2016

Agriculture

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“…The main reason is a reduction in the percentage of ewes having multiple births (Coop & Clark 1960;Thompson & Jagusch 1976;Coop 1977;Scales et ai. 1977), caused primarily by a decreased ovulation rate (Jagusch et ai.…”

Section: Introductionmentioning

confidence: 99%

Coumestans in lucerne and ovulation in ewes

Smith¹,

Jagusch²,

Brunswick³

et al. 1979

New Zealand Journal of Agricultural Research

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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 diet (x) and ovulation rate (y) was determined (y = 1.382 -O.004x). Levels of coumestans as low as 25 ppm in the diet depressed the ovulation rate of ewes fed lucerne pellets for 35 days. The depression in ovulation rate of ewes fed a high (100 ppm) level of coumestans was overcome by treatment with pregnant mare's serum gonadotrophin. It is suggested that coumestans exert their effect by interference with the release of follicle stimulating hormone from the pituitary gland.

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“…on coumestrol levels in herbage of lucerne (Medicago sativa) INTRODUCTION Lucerne is an important crop in New Zealand agriculture and is used both for grazing and hay production. However large depressions in ewe fertility, attributed to the presence of oestrogenic substances in the herbage (Shutt 1976), have been reported in flocks grazed on it at mating (Coop & Clark 1960;Thomson & Jagusch 1976;Coop 1977;Jagusch et al 1977;Scales et al 1977;Smith et al 1979). The phytoestrogens implicated are coumestrol and 4' -0-methyl coumestrol (Bickoff et al 1962;Coop 1977;Scales et al 1977;Smith et al 1979).…”

mentioning

confidence: 99%

Effect of pea aphid and bluegreen lucerne aphid (Acyrthosiphonspp.) on coumestrol levels in herbage of lucerne (Medicago sativa)

Kain¹,

Biggs²

1980

New Zealand Journal of Agricultural Research

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Field and glasshouse studies showed that infestations of pea aphid (Acyrthosiphon pisum Harris) and bluegreen lucerne aphid (A. kondoi Shinji) (BGA) caused increased coumestrollevels in herbage ofluceme (Medicago sativa cv. "Wairau"). Under field conditions log coumestrol concentration (ppm) was linearly related to aphid numbers and a reauction in stem length was associated largely with aphid damage. The coumestrol levels in severely aphid-damaged herbage were high enough to impair ewe fecundity. Glasshouse studies showed that similar levels of coumestrol were found in leaf and stem tissue of aphid damaged plants and that BGA infestations caused higher coumestrol levels than similar population levels of pea aphid.

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The reproductive performance of ewes mated on lucerne

Cited by 20 publications

References 6 publications

Fertility of Herbivores Consuming Phytoestrogen-containing Medicago and Trifolium Species

Fertility of Herbivores Consuming Phytoestrogen-containing Medicago and Trifolium Species

Coumestans in lucerne and ovulation in ewes

Effect of pea aphid and bluegreen lucerne aphid (Acyrthosiphonspp.) on coumestrol levels in herbage of lucerne (Medicago sativa)

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