These data present outcomes for monitoring of 18 mares at Sulphur herd management area, Utah. Data include Henneke body condition scores (BCS) and foaling success, measured by visual observations of mares during the 2021 breeding season (April to September 2021) to determine if mares had a foal at foot. Mares were treated with gonadotropin releasing hormone vaccine on September 2, 2020 and boosters were administered on November 1, 2020.