Altrenogest is a synthetic progestin used in veterinary medicine to regulate estrus in animals, particularly mares and swine. In mares, it synchronizes the estrous cycle to facilitate breeding schedules, controls ovulation timing for improved artificial insemination and natural breeding efficiency, suppresses behavioral estrus signs in performance horses to maintain focus during training or competitions, and manages reproductive disorders like persistent or irregular estrus. In swine, it synchronizes estrus in gilts and sows by suppressing follicular development during treatment, leading to synchronized ovulation post-withdrawal, which enhances pregnancy rates and farm productivity.