Location: Livestock Bio-Systems
Project Number: 3040-31630-001-001-I
Project Type: Interagency Reimbursable Agreement
Start Date: Jan 1, 2021
End Date: Jun 30, 2023
The objective of this research is to better understand how reproductive health in beef females influences reproductive function by examining the role of ovarian and systemic cytokine production in granulosa cell steroidogenesis, folliculogenesis, ovulation, and luteinization. We will investigate cytokine production by granulosa cells and determine if altered cytokine profiles are driving aberrant steroidogenesis by ovarian granulosa or luteal cells.
Experiments in Objective 1: 1A. Heifers will be classified based on antral follicle counts (AFC) as Low (bottom 10%) or High (top 10%). Selected heifers (n = 10/group) will go through a Select Synch protocol and be artificially inseminated 48 h after Lutalyse. On Day 16, reproductive tracts will be collected, and follicular fluid and granulosa cells will be isolated from the dominate follicle. Estrogen and cytokines will be measured from the follicular fluid. 1B. In the second experiment granulosa cells from the dominant follicle will be collected as described above. Total cellular RNA will be extracted from the granulosa cells and transcript abundance of markers associated with inflammation and apoptosis will be measured utilizing rt-qPCR. 1C. Uterine luminal fluid will be collected and analyzed for cytokine concentrations. The uterine lumen will also be swabbed for examination of white blood cells. Experiments in Objective 2: 2A. Heifers will be fed either rumen protected arginine or methionine and dominant follicular fluid will be analyzed for cytokine analysis. Granulosa cells will be isolated and measured for apoptosis and inflammatory transcript abundance. 2B. Serum will be collected from cows (n = 42) immunized against modified live or killed vaccine for bovine viral diarrhea virus (BVDV) to examine the influence of inflammatory responses on ovulation, luteinization and progesterone production. To assess the influence of the immunization on ovulation and progesterone production, serum samples will be analyzed for cytokine concentrations. Statistical Analysis of Data: Data will be analyzed using the MIXED procedure of SAS with the appropriate main effects for each study. Efforts: Abstracts will be submitted to both regional (Midwest ASAS) and national (SSR, ASAS) meetings. Abstracts for these meetings are due at two different times of the year (spring and fall) allowing to track progress by submitting new information to each meeting. Evaluation Plan: The first goal is the completion of the experiments described in Objective 1. Experiment 1A should be completed within the first 4-5 months of the project and 1B and C completed in the first year. Experiments in Objective 2 will be completed during the first 6 month of the project.