38 research outputs found

    Changes in the plasma concentrations of free and conjugated oestrogens in heifers after treatment to induce superovulation and the relationship with number of ovulations

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    Oestradiol-17β and conjugated oestrone, oestradiol-17β and oestradiol-17α were measured in peripheral plasma of heifers treated with PMSG/PGF-2α to induce superovulation. Changes in the concentration of each hormone were synchronous, the highest level being near oestrus. For a given number of ovulations the hormone with the highest concentration was total oestradiol-17α, then came total oestrone, total oestradiol-17β and oestradiol-17β. For each oestrogen, the maximum preovulatory concentration measured was significantly correlated with the number of ovulations; the regression line for total oestradiol-17β was twice as steep as that for oestradiol-17β. It is concluded that in animals treated to induce superovulation assay of total oestradiol-17α gives a better indication of the number of follicles induced to ovulate than does the more conventional assay of oestradiol-17β

    Sur la teneur des eaux en sélénium en relation avec la présence de terrains détritiques de l'Eocène supérieur (formation de Brenne) : Exemples de sources de la basse vallée de la Creuse (départements de l'Indre et de la Vienne)

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    L'analyse des eaux de la Roche-Posay (Vienne) connues pour leur teneur en sélénium et celle des eaux de la source de Saint-Aigny (Indre), près du Blanc, réputées pour avoir des propriétés comparables, met en évidence la faible teneur en sélénium des secondes. On rapproche la teneur élevée en sélénium avec la présence d'un manteau de terrains détritiques tertiaires aux environs de La Roche-Posay, alors qu'ils sont absents à Saint-Aigny

    Variabilité du moment d'apparition de l'oestrus et du pic pré-ovulatoire de LH chez la chèvre

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    Après traitement de synchronisation de l’œstrus chez la chèvre, l’étalement des venues en œstrus, du pic de LH et par conséquent des ovulations, constitue un facteur limitant de la réussite à I’IA lorsque celle-ci est réalisée à un moment prédéterminé. Une partie de cette variabilit6 pourrait être due à des caractéristiques physiologiques individuelles. Pour évaluer l’importance d’un tel facteur, nous avons étudié les délais d’apparition de l’œstrus et du pic de LH après injection d’oestradiol, ainsi que la répétabilité individuelle des réponses sur des chèvres ovariectomisées

    Synchronization of estrus in goats: the relationship between PMSG binding in plasma, time of occurrence of estrus and fertility following artificial insemination

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    Radioimmunoassay (RIA) was used to measure plasma eCG binding in dairy goats (n = 524) at the beginning of a progestagen/eCG treatment and 25 d after eCG administration. The eCG binding was not dependent on the age of the females but increased with the number of treatments they had previously received (3.4 % ± 4.8, N = 47 vs 9.6 % ± 13.2, N = 249; mean ± SD; P < 0.01 for goats treated 0 and 1 time vs those treated 2 to 5 times, respectively). The synchronization treatment led to an increase in the binding of eCG (7.1 % ± 10.9 before vs 28.3 ± 24.5 after treatment; P < 0.01). When eCG binding before treatment was higher than 5 % the onset of estrus was delayed: 37.9 % of goats came into estrus more than 30 h after sponge removal vs 7.4 % when eCG binding was lower than 5 % (P < 0.01). Fertility was significantly decreased when eCG binding was higher than 10 %. These results show that the repetition of treatment with eCG to induce estrus in goats increases eCG binding. This could explain the lowered efficiency of the hormonal treatment to synchronize estrus and the associated decrease in fertility when goats are inseminated at a predetermined time
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