PS-6 Nutrition During Early Pregnancy Impacts Offspring Ovarian Characteristics

Abstract During early pregnancy offspring are directly exposed to nutrients consumed by their mother, and the development of own reproductive tract is underway. The objective this research was determine how characteristics ovaries were affected different maternal rates gain during first trimester gestation in beef heifers. Before breeding antral follicle counts determined via ultrasound. Beginning at Angus heifers managed achieve one two gain: low (0.20 kg/d, n = 8; LG) or moderate (0.75 MG) for pregnancy, after which they as a single group through F1 calving. Calves remained with dams until weaning breeding. These heifer calves then synchronized bred sire using female sexed semen. On 84th day (approximate age 17 months) removed from tract, weighed, visible follicles counted. Cross-sections each ovary post-fixed embedded paraffin, 3 sections (5 µm, 10 between avoid counting more than once) stained Hematoxylin Eosin histological evaluation. Number primordial, primary, secondary, section. Data analyzed GLM procedure SAS significance declared P ≤ 0.05. CORR used calculate correlations pre-breeding counts, surface counts. Though no differences observed number (P 0.45), corpus luteum (CL) heavier 0.03) average ovarian length greater 0.04) LG compared those MG dams. No treatments 0.18). There correlation (r 0.73; 0.002) 0.60; 0.014), but there 0.10). Heavier CLs have positive amount progesterone released, essential maintenance. Longer lengths suggest area develop, indicative future success. corroborates previous reports regarding count ultrasound on extracted ovaries. findings demonstrate that nutrition impacts development.