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Effets de l'âge, de la parité et de la lactation de la jument poulinière sur l’embryon, le placenta et le développement du poulain

Abstract : Many mares in horse farms foal for the first time at an advanced age, after their sporting career. Since the mare can reproduce right after foaling, they can be pregnant and nursing, in order to produce one foal per year.The objective of this work was to study the effects of age, parity and lactation of the mare at insemination on the embryo, placenta at term, lactation and foal.Groups of young or old, nulliparous/primiparous or multiparous mares, lactating or not at the time of insemination were used. Gene expression was analyzed by RNA sequencing in embryos and placentas. Placental morphology was studied by histology and the growth and metabolism of the foals was followed up to 18 months.The results show that mares >10 years old are less fertile, with significant gene expression changes in the embryo, especially in the inner cell mass, related to energy metabolism and mitochondria. Their placenta is macroscopically similar to that of younger mares but with histological and gene expression changes indicating functional adaptations that result in the birth of a normal foal. These effects are amplified in nulliparous animals.In young nulliparous females, gene expression are observed in the embryo, without affecting viability. However, placental growth is reduced, resulting in intrauterine growth retardation. At birth, the foals are smaller but they catch up in their postnatal life.Changes in placental gene expression were observed in mares that were lactating at the time of insemination but normal sized foals are produced. Nevertheless, their growth is reduced at the end of lactation compared to controls, possibly related to less efficient lactation.These results highlight the importance of taking into account the age, parity and physiological stage of the mare in equine breeding.
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Submitted on : Tuesday, June 7, 2022 - 10:00:52 AM
Last modification on : Friday, August 5, 2022 - 2:38:11 PM

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  • HAL Id : tel-03689300, version 1

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Emilie Derisoud. Effets de l'âge, de la parité et de la lactation de la jument poulinière sur l’embryon, le placenta et le développement du poulain. Biologie de la reproduction. Université Paris-Saclay, 2022. Français. ⟨NNT : 2022UPASB010⟩. ⟨tel-03689300⟩

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