In mares with placentitis does the duration of antibiotic treatment affect foal outcome?

  • Elizabeth Barter Scone Equine



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PICO question

In mares with placentitis does treatment with long-term antibiotics result in improved foal viability when compared to repeated short courses of 7 to 10 days?


Clinical bottom line

Category of research question


The number and type of study designs reviewed

The literature search identified six publications that included length of antibiotic treatment and foetal outcome. The publications consisted of four non-randomised non-blinded controlled trials and two randomised non-blinded controlled trials

Strength of evidence

Collectively there was weak evidence to support either an intermittent or continuous antibiotic protocol in the treatment of placentitis in mares

Outcomes reported

The literature involved experimental induction of ascending placentitis with foal survival or viability as the outcome


Further research is required into the diagnosis of placentitis, length of treatment and choice of antibiotic/s to penetrate the uterus in a diseased state


How to apply this evidence in practice

The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.

Knowledge Summaries are a resource to help reinforce or inform decision-making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.


Open Access Peer Reviewed


Bailey, C. S., Macpherson, M. L., Pozor, M. A., Troedsson, M. H., Benson, S., Giguere, S., Sanchez, L. C., LeBlanc, M. M. & Vickroy, T. W. (2010). Treatment efficacy of trimethoprim sulfamethoxazole, pentoxifylline and altrenogest in experimentally induced equine placentitis. Theriogenology, 74(3), 402–12. DOI:

Baker, C. M., Ferrari, M. J. & Shea, K. (2018). Beyond dose: Pulsed antibiotic treatment schedules can maintain individual benefit while reducing resistance. Scientific Reports, 8(1). DOI:

Canisso, I. F., Ball, B. A., Cray, C., Squires, E. L. & Troedsson, M. H. (2015). Use of a Qualitative Horse-Side Test to Measure Serum Amyloid A in Mares With Experimentally Induced Ascending Placentitis. Journal of Equine Veterinary Science, 35(1), 54–59. DOI:

Carlotti, D. N., Jasmin, P., Gardey, L. & Ssanquer, A. (2004). Evaluation of cephalexin intermittent therapy (weekend therapy) in the control of recurrent idiopathic pyoderma in dogs: a randomized, double-blinded, placebo-controlled study. Veterinary Dermatology, 15(s1), 1–19. DOI:

Christensen, D. L., Moulton, K., Hopper, R., Walters, F. K., Cooley, A. J., LeBlanc, M. & Ryan, P. (2010). Evidence-based medicine approach to develop efficacious therapies for late-gestation mares presenting with uterine infections using and experimentally induced placentitis model. Animal Reproduction Science, 121, 345–346.

Cummins, C., Carrington, S., Fitzpatrick, E. & Duggan, V. (2008). Ascending placentitis in the mare: a review. Irish Veterinary Journal, 61(5), 307–313. DOI:

Curcio, B. R., canisso, I. F., Pazinato, F. M., Borba, L. A., Feijo, L. S., Muller, V., Finger, I. S., Toribio, R. E. & Nogueira, C. E. W. (2017). Estradiol cypionate aided treatment for experimentally induced ascending placentitis in mares. Special Issue: The David E. Bartlett Award for Lifetime Achievement in Theriogenology., 9, 454. DOI:

LeBlanc, M. M. (2010). Ascending placentitis in the mare: an update. Reproduction in Domestic Animals, 45, 28–34. DOI:

Macpherson, M. L., Giguere, S., Hatzel, J. N., Pozor, M., Benson, S., Diaw, M., Sanchez, L. C., Vickroy, T. W., Tell, L., Wetzlich, S. & Sims, J. (2013). Disposition of desfuroylceftiofur acetamide in serum, placental tissue, fetal fluids, and fetal tissues after administration of ceftiofur crystalline free acid (CCFA) to pony mares with placentitis. J Vet Pharmacol Ther, 36(1), 59–67. DOI:

Macpherson, M. L., Giguere, S., Pozor, M. A., Runcan, E., Vickroy, T. W., Benson, S. A., Troedsson, M. H. T., Hatzel, J. N., Larson, J., Vanden Berg, E., Kelleman, A. A., Sanchez, L. C. & LeBlanc, M. M. (2017). Pharmacokinetics of ceftiofur sodium in equine pregnancy. Journal of Veterinary Pharmacology Therapeutics, 40(6), 656–662. DOI:

Murchie, T. A., Macpherson, M. L., LeBlanc, M. M., Luznar, S. & Vickroy, T. W. (2006). Continuous monitoring of penicillin G and gentamicin in allantoic fluid of pregnant pony mares by in vivo microdialysis. Equine Veterinary Journal, 38(6), 520–525. DOI:

Murchie, T. A., Macpherson, M. L., LeBlanc, M. M., Luznar, S. & Vickroy, T. W. (2008). Detection of gentamicin and penicillin concentrations in allantoic fluid of pregnant pony mares by in vivo microdialysis. Havemeyer Foundation Monograph Series, 33.

Ryan, P., Crouch, J., Sykes, D., Moulton, K., Christiansen, D., Hopper, R., Read, R., Bennett, W. & LeBlanc, M. M. (2008). Experimentally induced placentitis in late gestation mares with Streptococcus equi zooepidemicus: prevention of pre-term birth. Havemeyer Foundation Monograph Series, 35–36.

Vincze, B., Baska, F., Papp, M. & Szenci, O. (2019). Introduction of a new fetal examination protocol for on-field and clinical equine practice. Theriogenology, 125, 210–215. DOI:

Waldridge, B. M. & Pugh, D. G. (2001). Equine placentitis. Compendium on Continuing Education for the Practicing Veterinarian, 23, 573–575.





Vol. 5 No. 3 (2020): The third issue of 2020

Section: Knowledge Summaries

Categories :  Small Animal  /  Dogs  /  Cats  /  Rabbits  /  Production Animal  /  Cattle  /  Sheep  /  Pig  /  Equine  / 

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