The aim of this study was to test whether low dose oxytocin i.v. injection
once a day to mares diagnosed as being ready for birth by mammary secretion
calcium strip test measurements could be used as a reliable method to indu
ce parturition and/or predict the mare would not foal during the following
night if parturition did not occur within 2 h of treatment.
Fifty-one near-term Haflinger mares were used and a single injection of 2.5
iu oxytocin was given between 1700 and 1900 h, including 10 mares used as
controls which were administered a placebo, Administration of oxytocin resu
lted in the delivery of a normal foal within 120 min in 95% of mares. Twent
y-four out of 38 (63%) treated animals foaled in response to the first oxyt
ocin injection, 9 out of 38 (24%) in response to the second injection and 3
out of 38 (8%) in response to the third treatment. Two out of 38 (5%) trea
ted mares foaled during the night irrespective of treatment whereas 7 out o
f 10 (70%) control mares foaled during the night. It was concluded that the
major advantage of injecting a daily low dose of oxytocin appears to be th
at such a low dose induces delivery only in mares carrying a mature fetus a
nd which are ready to foal.