Déclanchement Simultané De l'ŒSTRUS Dans Un Lot De Brebis Avec Possibilité De Gestation Ultérieure

Dauzier, L.; Wintenberger, Suzanne

doi:10.1051/animres:19520405

Cited by 10 publications

(4 citation statements)

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“…intervals, as against daily or longer intervals. Robinson (1954a) confirmed the findings of Dutt (1952Dutt ( , 1953 and Dauzier & Wintenberger (1952) that progesterone alone can induce ovulation and occasionally oestrus in the anoestrous ewe, but the response appeared to be made much more positive and uniform when gonadotrophin followed the progesterone treatment. He concluded from his experiments that progesterone apparently acts through the conditioning of a receptor or receptor tissues to respond to a subsequent low level of endogenous oestrogen (produced during the growth of the graafian follicles).…”

supporting

confidence: 58%

The use of progesterone and serum gonadotrophin (P.M.S.) in the control of fertility in sheep. II. Studies in the extra-seasonal production of lambs

Gordon

1958

J. Agric. Sci.

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Section 11. A total of 189 ewes, of various breeds and crosses were used in slaughter experiments conducted in anoestrum during 1953–6. The ewes were of mixed ages, and included four lambs, aged 52–71 days.2. Ewes received P.M.S. in different combinations with progesterone to induce co-incident oestrus and ovulation. Progesterone was employed in three forms, as a solution in oil, as a micro-crystalline suspension and as fused pellet implants. One hundred ewes were injected with the oil solutions, eighty-five with the suspensions and four received the pellet form of the hormone.3. The percentage of ewes that came in oestrus (oestrous response) was higher in those treated for a 5-day period than in those treated for a 3-day period with progesterone in oil P.M.S. being administered 2 days after the final progesterone injection. The oestrous response in ewes receiving progesterone over a 13-day period was no higher than in those treated over 5 days.4. 172 ewes' tracts were examined for ovulations. In those sheep (excluding the four young lambs) which came in oestrus, all had ovulated. Ovulation was apparently inhibited in some ewes which received progesterone in suspension form. The ovulation rate following treatment with 700 i.u. whole serum P.M.S. was higher than that where 750 i.u. purified serum was employed.5. Forty-one of the ewes which came in oestrus were slaughtered 41–120 hr. after estimated onset of oestrus. Seventy-six of the ninety-two ova shed by these animals were recovered. 81·3% of recovered ova were cleaved. Of thirty-four ewes slaughtered 61–120 hr. after oestrus, thirty-two (94·1%) yielded one or more apparently normal fertilized ova. There was no evidence that fertility in the Suffolk rams employed in matings decreased to the point where it might affect conception in out-of-season breeding.

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confidence: 58%

The use of progesterone and serum gonadotrophin (P.M.S.) in the control of fertility in sheep. II. Studies in the extra-seasonal production of lambs

Gordon

1958

J. Agric. Sci.

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“…Sensitivity to oestradiol and reliability in response were restored when a period of treatment with progesterone preceded oestradiol (Robinson 1954a(Robinson , 1954b. The realization that oestrus in the ewe was a function of oestrogen secreted after a period of progesterone provided support for the observation (Dauzier and Wintenberger 1952;Dutt 1952;Robinson 1952) that ovulation induced in the anoestrous ewe by pregnant mare serum gonadotrophin (PMSG) was accompanied by oestrus only if the PMSG was preceded by progesterone. The need for progesterone prior to oestrogen also provided the explanation for the observation made 20 years previously (Grant 1934) that the first ovulation of the breeding season was usually not accompanied by oestrus (,silent heat').…”

Section: Relationship Between Oestrogen and Progesterone In Oestrus Imentioning

confidence: 87%

The Ovariectomized Ewe: Its Contribution to Controlled Breeding

1988

Aust. Jnl. Of Bio. Sci.

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The ovariectomized ewe has been used to establish principles and procedures which have proved invaluable in controlled breeding in entire animals. Bioassays in the ovariectomized ewe, using the end-point of oestrous behaviour, have been used to identify potent and rapidly metabolized progestagens which were subsequently used to control the time of oestrus and ovulation in cyclic ewes effectively, and to induce oestrus and ovulation in anoestrous ewes. Steroid hormone treatment of the ovariectomized ewe has been used to study relationships between the ovary and the pituitary - hypothalamic axis, to examine transport of embryos within the female tract and to establish the steroid hormone requirements of early pregnancy.

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“…On the basis of results obtained when androgen was given prior to PMS-induced ovulation in the anoestrous ewe, Cole (1948) suggested that androgen may be responsible for the induction of oestrous behaviour in the sheep. Subsequently Dauzier & Wintenberger (1952), Dutt (1952) and Robinson (1952Robinson ( , 1954 found that a period of progesterone pretreatment prior to PMS-induced ovulation commonly resulted in an apparently normal oestrus accompanying this ovulation. Studies with spayed ewes showed that normal oestrus-behavioural and vaginaldepends on an interaction between progesterone and oestrogen.…”

Section: Introductionmentioning

confidence: 99%

Oestrogenic and Anti-Oestrogenic Activity of Androgens in the Ewe

Lindsay¹,

Robinson²

1964

Reproduction

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Seventy-two spayed crossbred ewes were used in a series of five successive tests, at intervals of 15 days, in a study of the actions and interactions of androgen, oestrogen and progesterone on behavioural and vaginal oestrous responses.Androgen and oestrogen were additive in their action (128 vs. 62 services; P<0\m=.\001) on behavioural response, but androgen almost completely inhibited the expected vaginal response to oestrogen.There was a significant linear decline in behavioural sensitivity from test to test; in the five successive tests, forty-eight, forty-three, thirtyseven, thirty-two and thirty ewes were served (P<0\m=.\001). This refractory condition was partly offset by progesterone pretreatment (P<0\m=.\001), but oestrogen was necessary to maintain a constant state of psychic reactivity to androgen (P<0\m=.\001).A highly significant linear dose-response relationship was demonstrated with both testosterone and testosterone propionate (P<0\m=.\001).

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Déclanchement Simultané De l'ŒSTRUS Dans Un Lot De Brebis Avec Possibilité De Gestation Ultérieure

Cited by 10 publications

References 0 publications

The use of progesterone and serum gonadotrophin (P.M.S.) in the control of fertility in sheep. II. Studies in the extra-seasonal production of lambs

The use of progesterone and serum gonadotrophin (P.M.S.) in the control of fertility in sheep. II. Studies in the extra-seasonal production of lambs

The Ovariectomized Ewe: Its Contribution to Controlled Breeding

Oestrogenic and Anti-Oestrogenic Activity of Androgens in the Ewe

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