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Effets d'une restriction alimentaire après vêlage chez la vache allaitante sur la fertilité à l'oestrus induit, la sécrétion de LH et l'activité ovarienne : liens avec le métabolisme énergétique et intérêt d'une supplémentation énergétique avant la mise à la reproduction

Abstract : The effects of feed restriction after calving were investigated in Charolais beef cows on epidemiological and biological reproduction parameters. Firstly, two epidemiological surveys have highlighted the influence of body condition score on the duration of postpartum anoestrus and on fertility at induced estrus. In herds with calvings d)lIing Winter, most of the cows presented allow body condition. In this case, a short period of energy supplementation or flushing before mating may improve the ovulation rate. Therefore, three trials were realised in an experimental station between 1995 and 1997 to study the effects of a flushing on biological reproduction parameters such as LH secretion, follicular dynamics and steroidogenesis. It has been shown 1/ that a feed restriction after calving results in a decrease in intrafollicular estradiol concentrations measured in large follicles 30 days after calving,without an effect on small follicles, 2/ that a flushing may improve the number of large follicles within a week and increase the plasmaticestradiol concentrations after implant removal, without an effect on LH secretion. Glucose loads have been performed to investigate the modifications of insulin metabolism and induced lower insulin concentrations in supplemented cows than in restricted cows, indicating that the sensibility of the tissues to insulin was increased. To conclude, a short period of energy supplementation may stimulate ovarian activity by a metabolic signal, which might involve insulin.
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http://docnum.univ-lorraine.fr/prive/SCD_T_2000_0303_PONSART_POSIERE.pdf
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https://hal.univ-lorraine.fr/tel-01746895
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Submitted on : Thursday, March 29, 2018 - 10:47:08 AM
Last modification on : Thursday, December 17, 2020 - 2:35:28 PM

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Claire Ponsart-Posière. Effets d'une restriction alimentaire après vêlage chez la vache allaitante sur la fertilité à l'oestrus induit, la sécrétion de LH et l'activité ovarienne : liens avec le métabolisme énergétique et intérêt d'une supplémentation énergétique avant la mise à la reproduction. Médecine humaine et pathologie. Université Henri Poincaré - Nancy 1, 2000. Français. ⟨NNT : 2000NAN10303⟩. ⟨tel-01746895⟩

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