B-mode and Doppler ultrasonography in pony mares with experimentally induced ascending placentitis
Article first published online: 27 NOV 2012
© 2012 EVJ Ltd
Equine Veterinary Journal
Special Issue: 58th Annual Convention of the American Association of Equine Practitioners. Guest Editors: N. White, D. Sellon and B. Ball. Publication of this supplement was supported by the American Association of Equine Practitioners
Volume 44, Issue Supplement S43, pages 88–94, December 2012
How to Cite
Bailey, C. S., Heitzman, J. M., Buchanan, C. N., Bare, C. A., Sper, R. B., Borst, L. B., Macpherson, M., Archibald, K. and Whitacre, M. (2012), B-mode and Doppler ultrasonography in pony mares with experimentally induced ascending placentitis. Equine Veterinary Journal, 44: 88–94. doi: 10.1111/j.2042-3306.2012.00658.x
- Issue published online: 27 NOV 2012
- Article first published online: 27 NOV 2012
- NCSU CVM First Award Grant
- Veterinary Scholars Program at North Carolina State University
Reasons for performing study
Early, accurate diagnosis of ascending placentitis in mares remains a key challenge for successful treatment of the disease. Doppler ultrasonography has shown promise as a tool to diagnose pregnancy abnormalities and is becoming more available to equine clinicians. However, to date, no studies have prospectively compared this technique to standard B-mode measurement of the combined thickness of the uterus and placenta (CTUP).
The objective of the current study was to compare Doppler and B-mode ultrasonography for the detection of experimentally-induced ascending placentitis in mares.
Eleven healthy pony mares in late gestation were used in this study. Placentitis was induced in 6 mares between Days 280 and 295, while 5 mares served as negative controls. All mares were intensively monitored until delivery. Fetal heart rate, CTUP, uterine artery blood flow (resistance index, pulsatility index, arterial diameter and total arterial blood flow) and physical examination findings were recorded at each examination. Mares with an increased CTUP above published values were treated in accordance with published recommendations. Foals and fetal membranes were examined at birth. Ultrasonographic parameters were compared between groups using ANOVA. Foal viability and histological presence of placentitis were compared using a Fisher's exact test.
The CTUP was increased above normal in 5 of 6 inoculated mares within 3 days after inoculation (P = 0.05). The sixth inoculated mare was excluded from subsequent data analysis. Uterine artery blood flow, physical examination findings and fetal heart rate were not different between groups. Gradual increases in CTUP, arterial diameter and total arterial blood flow were detected with increasing gestational age in the control mares (P = 0.02, P = 0.00001 and P = 0.00001, respectively).
The CTUP, but not uterine blood flow, was different between groups (P = 0.00001). Recorded CTUP values for control pony mares were similar to previously published values for light breed horses.