Traitement ciblé de l'infertilité post-partum chez la vache laitière

奶牛盈利能力的头号问题是生育率低，这会导致延误、治疗和过早淘汰。低生育率是几个因素结合的产物，但似乎在产后60天左右达到顶峰，正好是生产者开始授精的时候。对产后情况的分析表明了低生育率的潜在因素：子宫复旧不完全、感染、乳腺炎和炎症状态，但最可能的怀疑是由高泌乳量奶牛、有限的采食量、次优的食物质量等引起的负能量平衡。因此，我们通过使用强大的转录组学方法观察对环境的完整反应，分析了卵巢的前景。我们首先观察了奶牛在产后30-60-90和120天不同时期的同步优势卵泡，使用120天作为对照参考，并说明在60天，一些基因通路在这些卵泡中不能正常工作，特别是视黄酸依赖性途径。根据BHB的动物代谢分析（β-羟基丁酸）水平已经确定了这些动物中表达不足的2条途径：维生素A和维生素D依赖性途径。为了将基因组信息转化为实践，我们设计了一个简单的实验，该实验将作为缩小规模的初步干预，以证明更大规模的临床试验是合理的。根据不存在影响生育力的明显疾病，在产后50天时选择产后动物。将对动物进行血液BHB测量采样。一半动物（24）将在第50天和第70天注射2次维生素A-D，另一半动物将作为对照（24）。此外，还将比较对开放日数、授精和兽医怀孕费用的影响。目的是为处于授精关键期的高BHB奶牛提供简单的个体化治疗。这个概念似乎过于简单化，但似乎卵巢可以感受到季节性环境，如新鲜的草（维生素A）和春天（维生素D）作为未来能量供应的代谢指标，并促进生育。

The number one problem in dairy cows profitability is low fertility which causes delays, treatments and premature culling. The low fertility is the product of a combination of several factors but seems to peak at around day 60 post-partum exactly at the time where producers are starting to inseminate. The analysis of the post-partum context indicates the potential factors involved in low fertility: incomplete uterine involution, infection, mastitis and inflammation status but the most likely suspect is the negative energy balance caused by high milking cows, limited intake capacity, suboptimal quality of food etc. Therefore, we have analysed the ovarian perspective by looking at the complete response to the environment using the powerful transcriptomic approach. We first looked at the synchronized dominant follicles of cows at different period post-partum 30-60-90 and 120, using 120 days as the control reference and illustrates that at 60 days a few gene pathways are not functioning correctly in these follicles, especially the retinoic acid dependant path.A metabolic analysis of the animals according to BHB (beta hydroxy butyrate) level has identified 2 pathways under expressed in these animals: vitamin A and vitamin D dependant pathways. To translate the genomic information into practice we have design a simple experiment that would serve as a preliminary intervention on a reduced scale to justify a larger clinical trial. Post-partum animals will be selected at 50 post-partum based on the absence of obvious diseases which would impact fertility. The animals will be sampled for blood BHB measurements. Half of the animals (24) will be treated with 2 injections of vitamins A-D at days 50 and 70 and the other half will serve as control (24). In addition, the impact on the number of open days, insemination and veterinary cost to obtain a pregnancy will be compared. The goal is to provide a simple individual treatment to high BHB cows in the critical period for insemination. This concept may seems too simplistic but it seems that the ovary can sense the seasonal context as fresh grass (vit A) and spring (vit D) as metabolic indicator of future energy supply and facilitate fertility.