Pregnancy monitoring in mares

The abstract provides a quick overview of the procedures available and why they may be relevant to managing a pregnant mare.
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Pregnancy monitoring in mares: Ultrasonographic and endocrine approaches
Reprod Domest Anim. 2023 Sep;58 Suppl 2:34-48. doi: 10.1111/rda.14392. Epub 2023 Jun 13.
Authors
Catherine D Renaudin 1 , Alan J Conley 1
Affiliation

1 Department of Population Health & Reproduction, School of Veterinary Medicine, University of California Davis, Davis, California, USA.

PMID: 37191550
DOI: 10.1111/rda.14392

Abstract

Methods to diagnose and monitor equine pregnancy continue to advance with improved instrumentation enabling the development of novel, non-invasive approaches to assess fetal well-being and viability using ultrasound and endocrine testing. From early embryonic loss to placentitis, that is typically encountered later in gestation, fetal viability and development as well as placental function can be evaluated using two fundamentally different, structural and functional, approaches. Ultrasound provides structural information on embryonic and fetal growth using such parameters as combined thickness of the uterus and placenta (CTUP), visual assessment of fetal fluids, activity, heart rate and multiple biometrics involving the fetal head and eyes, limbs and joints among many others, depending on the stage of gestation. Endocrine profiles that include progesterone and 5α-dihydroprogesterone, other metabolites, androgens and estrogens can be evaluated simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS) providing more functional information on fetal and placental competence and development. Endocrine information can be used in making clinical decisions including the need for progestin supplementation or when it can cease, and even estimating gestational stage in mares that cannot be easily palpated or scanned, as with mini-breeds or rancorous animals most notably. When used together, monitoring gestation by ultrasound and hormonal analysis provides unusual insight into feto-placental well-being and the progress of pregnancy, helping to identify problems needing therapeutic intervention.

Keywords: equine; fetus; hormone; ultrasound.

© 2023 The Authors. Reproduction in Domestic Animals published by Wiley-VCH GmbH.