The effects of pairing a low quality forage with excess amounts of metabolizable protein (MP) supplementation from a moderately abundant rumen undegradable protein (RUP) source (corn gluten meal; 62% RUP) on ovarian function of beef cows was evaluated in a 60-day trial. Non-pregnant, non-lactating cows (n = 16) were offered ad libitum access to cornstalks and fed 1 of 2 isocaloric diets (0.48 NEm/lb) and supplemented primarily with corn gluten meal to provide 125% MP requirements (MP125) or 150% MP requirements (MP150). It was observed that cows offered MP at 150% in the diet from a moderately abundant RUP source had increased ovulatory follicle diameter, average antral follicle count and corpus luteum (CL) development compared to 125% MP. Therefore, excess dietary CP supplementation from a RUP source at 150% of MP requirements appears to enhance ovarian parameters of beef cows when fed with low quality forage compared to supplementation at 125% of MP requirements.