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Veterinary medicine and science2025; 12(1); e70697; doi: 10.1002/vms3.70697

Progestagens Monitoring in 147 Mares in Order to Induce Foaling With Oxytocin.

Abstract: A total of 147 mares of different breeds (110 were sport or race horses, often very valuable) have been monitored over 5 years from 2012 to 2016. When at or near term, the mares were monitored in order to induce foaling, by checking the mammary development by palpation, analysing the colour and consistency of the precolostrum, estimating the calcium and antibodies concentrations in the precolostrum and by measuring the plasmatic progestagens concentration every day at 6 p.m. At the end of gestation, it has been observed that the progestagens rate levelled off (the top concentration varies from mare to mare: it can be as low as 35 ng/mL or up to 260 ng/mL) before falling sharply. Parturition was induced when the progestagens concentration fell of about 50% within 24 to 48 h. Induction was performed at 9 p.m. in 93 mares that followed the rule of the drop of progestagens (to respect the nycthemeral cycle) by a single IM oxytocin injection from 10 to 50 UI according to the weight of the mare (120 to 900 kg). Following the oxytocin injection, 90% (n = 84) of the foals were born within 20 to 50 min, 7.5% after 60 min (usually due to an excess of volume or dystocia), all alive and viable. Thirty to 60 min after birth, a manual delivery was performed for 71% (n = 66) of the mares. Among the 54 mares with spontaneous parturition (not induced because of insufficient proof of imminent birth), all foals were alive except for 2 twins that were found dead. A manual delivery was necessary for 17% (n = 9) of them. A 50% drop of the progestagens concentration is a good indication of the imminence of foaling: It is then safe to induce foaling, which usually results in a higher probability for a healthy foal and a reduced risk of genital lesions to the mare. Au cours de 5 saisons de monte entre 2012 et 2016, 147 juments de races différentes, dont 110 juments de selle, souvent de valeur, appartenant à différents propriétaires, ont été confiées pour surveillance du poulinage.A la date du terme ou à l'approche du terme, elles ont été suivies en se basant sur le développement de la mamelle(palpation), la couleur et la consistance du précolostrum(traite), complétés par une estimation quotidienne de la teneur en calcium et en anticorps du précolostrum et un dosage des progestagènes plasmatiques. Le taux de progestagènes évolue en plateau en fin de gestation mais, selon les juments, il est très variable, il peut osciller autour de 35 ng/mL ou beaucoup plus, le record a été de 260 ng/mL. Lorsqu'il chute d'environ 50% en 24 à 48 h, la parturition a, alors, été déclenchée chez 93 juments, par une injection de 10 à 50 UI d'ocytocine, en fonction de leur poids(120 à 900 kg) par la voie I.M., à 21 h pour respecter le rythme nycthéméral des poulinages.Tous les poulains sont nés vivants et viables:90% 20à 50 mn après l'injection,7.5% plus de 60mn plus tard (excès de volume ou dystocies).Trente à 60mn plus tard, 71% des juments sont délivrées manuellement. Chez les 54 témoins (qui ne répondaient pas à tous les critères retenus ou qui poulinaient entre 19 h, dosage des progestagènes, et 21 h, heure prévue pour l'injection d'ocytocine), tous les poulains sont vivants sauf 2 jumeaux retrouvés morts. La délivrance manuelle a été nécessaire chez 17% d'entre elles. Une chute de 50% du taux de progestagènes permet donc d'induire le poulinage sans risque de prématurité du poulain ce qui augmente les chances d'avoir un poulain vivant et une jument sans lésion génitale grave. SUMMARY: A 50% drop of the progestagens concentration within 24 to 48 h indicates imminent parturition Progestagens blood concentration, udder development, and precolostrum monitored together allows generally to determine the night of parturition A healthy foal is obtained if parturition is induced after the fall in blood progestagens associated with sufficient udder development and quality of colostrum.
Publication Date: 2025-11-27 PubMed ID: 41306086PubMed Central: PMC12658334DOI: 10.1002/vms3.70697Google Scholar: Lookup
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  • Journal Article

Cite This Article

APA
Tainturier D, Tainturier B, Michaud S, Briand-Amirat L, Topie E, Moreno D. (2025). Progestagens Monitoring in 147 Mares in Order to Induce Foaling With Oxytocin. Vet Med Sci, 12(1), e70697. https://doi.org/10.1002/vms3.70697

Publication

ISSN: 2053-1095
NlmUniqueID: 101678837
Country: England
Language: English
Volume: 12
Issue: 1
Pages: e70697
PII: e70697

Researcher Affiliations

Tainturier, Daniel
  • Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes Cedex, France.
Tainturier, Benoit
  • French Military Service, 23ème Groupe Vétérinaire, Garde Républicaine, Paris Cedex, France.
Michaud, Sandrine
  • Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes Cedex, France.
Briand-Amirat, Lamia
  • Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes Cedex, France.
Topie, Emmanuel
  • Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes Cedex, France.
Moreno, Diego
  • Biotechnology and Pathology of Reproduction, Nantes-Atlantic National College of Veterinary Medicine, Food Science and Engineering, Oniris, Nantes Cedex, France.

MeSH Terms

  • Animals
  • Horses / physiology
  • Horses / blood
  • Female
  • Oxytocin / administration & dosage
  • Oxytocin / pharmacology
  • Progestins / blood
  • Pregnancy
  • Parturition / drug effects
  • Oxytocics / administration & dosage
  • Oxytocics / pharmacology

Conflict of Interest Statement

None of the authors have any conflicts of interest to declare.

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