Systems approach to deciphering molecular mechanisms of infertility in lactating dairy cows with subclinical ketosis

点击翻译按钮获取中文摘要

Sustainable dairy production is a function of dairy cow longevity. Reduced longevity is not profitable because of reduced lifetime milk yield and it is environmentally unsustainable because more replacement heifers have to be maintained in the herd. Reproductive failure, which is fundamentally due to ovarian dysfunction, is the number one cause of culling. Therefore, understanding the mechanisms of ovarian dysfunction is urgently needed to develop diagnostic, therapeutic and managemental strategies to optimize reproductive performance of lactating dairy cows. The metabolic stress that the cows experience during early lactation has long been proposed to negatively impact reproductive processes. Subclinical ketosis (SCK) is the most prevalent metabolic disorder in dairy herds. We hypothesize that metabolic alterations associated with SCK have unique effects on ovarian follicular gene expression. The objective of this project are to determine metabolic and hormonal levels and to profile gene expression in the liver and ovarian granulosa cells of healthy and SCK cows. These objectives are aligned with the research priority, "Dairy cattle fertility and reproduction" of our industry partner, Novalait. We propose to use systems biology approach employing RNA sequencing technology, molecular biology and bioinformatics tools to investigate the liver and ovarian functions in healthy and SCK cows. Other molecular biology techniques and on-farm data including production, nutritional, reproduction and culling rate will also be used link metabolic perturbation to ovarian dysfunction. The results of this project will enhance our understanding of the impact of SCK on ovarian functions and thus lactating cow fertility. The data generated may contribute to identification of marker sets in milk that will predict cows suffering from SCK and consequent reproductive dysfunction. Such markers could be used to advise farmers of the cows with potential reproductive problems and needing appropriate intervention to best achieve fertility and longevity.