Use of ultrasonography in reproductive management of mares

Abstract
Since the introduction of ultrasonography to the equine veterinary field in the early 1980's, its use as a diagnostic tool has expanded dramatically. Initially used strictly for pregnancy detection, more recent applications in reproduction include: 1) monitoring follicular changes and predicting ovulation; 2) confirmation of ovulation and evaluation of corpus luteum morphology; 3) estimating the stage of the estrous cycle; 4) diagnosing ovarian irregularities and pathology; 5) detection of twins and embryo reduction; 6) determining embryonic death; 7) evaluation of uterine pathology; and 8) evaluation of testes and accessory sex glands of stallions. Ultrasonography has now become an indispensable component of an equine embryo transfer program. The purpose of this review is to discuss some of the uses of ultrasound in reproduction in the mare with emphasis on its application in an embryo transfer program.