PSVII-15 - Polymorphism of the Follicle Stimulating Hormone Receptor Does Not Impact Reproductive Performance or in-vitro Embryo Production in Beef Heifers

Assisted reproductive technologies are used to propagate desirable genetics in a shorter timeframe. Females selected are utilized as donor females and there is variability in the response to ovarian stimulation with the use of follicle stimulating hormone (FSH). The FSH receptor (FSHR) c.337 C >G variant was reported to result in fewer viable embryos in an ovarian stimulation protocol. We, therefore, hypothesized that FSHR c.337 C >G would result in reduced blastocyst development in -vitro. Beef heifers were genotyped and selected based on the c.337 C >G FSHR genotype (CC, CG, GG; n = 12/genotype). Estrus was synchronized with a Select Synch protocol, and heifers were slaughtered 5 days after induced ovulation. Anterior pituitaries, serum and reproductive tracts were collected at slaughter for analysis. Cumulus oocyte complexes (COCs) were collected and pooled within genotype for in-vitro fertilization and subsequent blastocyst development. Percent data were analyzed with PROC GLIMMIX using the logit function in SAS. Continuous data were analyzed with PROC MIXED in SAS. No differences were observed in anterior pituitary weights, serum progesterone, corpus luteum weights, surface follicle counts, histological follicle counts or follicular fluid estradiol concentration (P > 0.1) due to FSHR genotype. Cleavage and blastocyst rates were not affected due to FSHR genotype (P > 0.1). While previous literature reports differences in viable embryos quality after an in vivo superovulation protocol due to this FSHR variant, the sample size is limited. The data collected from this study have an equal number of females across the different variants. Thus, this FSHR variant does not influence follicle counts, estradiol production, or blastocyst development in-vitro in beef heifers and may not be a useful marker for predicting response to assisted reproductive technologies. USDA is an equal opportunity provider and employer.