Abstract
While sequence variation can be informative to associate regions of the genome with specific traits and improve genetic selection, the epigenome may provide a more powerful tool to manage cattle. Identifying practices that are producer friendly and effectively control epigenetic function within animals is crucial to translating developmental programming to a production setting. Initial studies of developmental programming investigated how environmental or nutritional stresses during fetal and peri-natal development impacted performance of animals later in life. These studies demonstrated changes in methylation, alterations in transcript abundance, and negative impacts on physiology, but they also suggested that we may be able to beneficially impact the epigenome and developmentally program animals to excel in their niche in the production system. Maternal nutritional status during the third trimester influenced date of conception of female progeny in several studies but failed to do so in other studies. Transcriptomic analyses provided evidence that nutritional treatments alter mRNA abundance in brain, liver, muscle, and ovary, but does not conclusively demonstrate that this is due to functional changes in the epigenome. If developmental programming is to be applied in production systems, responses must be consistent and beneficial. Reducing nutrient intake in heifers during peri-pubertal development increased number of primordial follicles in the ovaries and reproductive longevity. While nutritional programming of the ovarian reserve in peri-pubertal heifers appears to occur consistently across locations and studies, it does not ensure that subsequent environmental stressors will not induce changes in the ovarian reserve that will negate beneficial effects. These studies demonstrate that it is possible to developmentally program the epigenome in cattle in ways that will improve production traits; however, there remains a need for studies to improve the consistency of response and to determine best practices that fit into production systems. USDA is an equal opportunity provider and employer.
MicroRNA profiling and identification of let-7a as a target to prevent chemotherapy-induced primordial follicles apoptosis in mouse ovaries
