Induction of Parturition with Daily Low‐dose Oxytocin Injections in Pregnant Mares at Term: Clinical Applications and Limitations

Abstract

The aim of the present study was to evaluate the clinical applications and limitations of daily low-dose oxytocin injections for the induction of parturition in pregnant at term mares, the attention was focussed on the efficacy of the treatment and on its possible negative effects on mare and foal. Three-hundred and fifty pregnant full term Standardbred mares were used: 176 were allowed to foal spontaneously, 174 were treated daily with 3.5 IU of oxytocin i.m. when mammary secretion showed a calcium concentration >or= 200 ppm. For each mare, gestational length, outcome and duration of foaling, placenta expulsion time were recorded. Physical and behavioural characteristics of each foal were also recorded. Administration of oxytocin resulted in the delivery of a normal foal within 120 min in 68.9% of treated mares: 51.3% responded to the first oxytocin administration, 14.2% to the second and 3.4% to the third. No significant difference between treated and control mares was observed in the gestational length (340 +/- 8 days vs 337 +/- 7 days), duration of foaling (10 +/- 5.6 min vs 11 +/- 4.9 min), incidence of dystocia (1.4% vs 1.7%) and failure of rupture of the allantochorion (0% vs 0.6%). No significant difference was observed in the incidence of placental retention between treated and control groups (8.1% vs 6.3%). Physical and behavioural characteristics were normal in foals of both groups. In conclusion, daily injections of low doses of oxytocin in at term mares showed only moderate efficacy for inducing parturition. However, the easy applicability and the complete safety for both mare and foal, of this method of foaling induction makes it a useful tool to simplify the management of mares in commercial stud farms.

Peripartum findings and blood gas analysis in newborn foals born after spontaneous or induced parturition

“…We found that gestational length was within the reference range and was similar in SF and IF groups, which suggests that low-doses of OX successfully induce parturition if mares are ready for parturition, as previously demonstrated [11][12][13].…”

“…The length of the II stage of parturition was within the reference interval (<30 minutes) [1,22] in both groups and no differences were found between SF and IF mares. Although these re-sults do not agree with Panzani et al [13] who reported a shorter expulsion time in treated mares, they are in line with others who reported similar lengths both in treated and control mares using either low-dose OX [12] or other OX-based induction protocols [8].…”

“…In more recent studies, parturition in mares at term was induced by low doses of OX once a day, and the authors [11][12][13] reported that this procedure was safe for both mares and foals.…”

Gestational length in Carthusian broodmares: effects of breeding season, foal gender, age of mare, year of parturition, parity and sire

“…Up to now, GL data have been reported for Thoroughbreds (Hintz et alElliot et al 2009, Sharma andDhaliwal 2010), Freibergers (Giger et al 1997), Lipizzaners (Heidler et al 2004), Friesians (Sevinga et al 2004), Quarter Horses (Guay et al 2002, Duggan et al 2008, Standardbreds (Marteniuk et al 1998, Villani andRomano 2008), Criollo (Winter et al 2007), Pantaneira (Zúccari et al 2002), Andalusians (Valera et al 2006), Arabians (Demirci 1988, El-Wishi et al 1990, Valera et al 2006, Cilek 2009, Meliani et al 2011) and Andalusians of Carthusian strain (Pérez et al 2003). In all these studies, GL ranges between 330 and 350 days.…”

A regression model including fetal orbit measurements to predict parturition in Standardbred mares with normal pregnancy

“…In veterinary medicine, fetal morphometry is used to evaluate fetal development, to estimate gestational age and could be useful for predicting parturition. Normal gestation length in Standardbred mares ranges between 322 and 389 days [23][24][25] and it could be influenced by many factors such as season, sex [26], daylight [27,28], geographical region, latitude [25,29,30], sire [23], mare's age and parity [31][32][33][34][35][36][37]. The selected covariates used for the regression tree (the two ocular diameters, mare's age and parity) were the ones that from a practical point of view are available for the veterinary practitioner.…”