Three methods of oxytocin-induced parturition and their effects of foals.

The research article explores and compares three methods of inducing parturition (birth) in horses using oxytocin, and examines their effects on newborn foals. The researchers concluded that while the method of oxytocin-induced birth doesn’t impact the health of the newborn, factors like the length of time from induction until birth, the degree of cervical dilatation, and intrapartum complications do affect the success of the induction.

Research Methodology

The study was conducted as a prospective randomized controlled trial involving 16 pregnant mares. Three different treatments were used to induce parturition:

• Group 1: 75 units of oxytocin, given as an intramuscular injection.
• Group 2: 15 units of oxytocin, administered intramuscularly every 15 minutes, for a maximum total of 75 units.
• Group 3: 75 units of oxytocin given via an intravenous drip in a litre of saline solution, at one unit per minute, for a maximum total of 75 units.

Subsequently, various parameters were measured in the mares and foals. In the mares, factors relating to the parturition process were recorded; while in the foals, blood gas values, vitality indices, and plasma cortisol concentrations were assessed.

Findings

The experiment found that mares in Group 3 had a shorter interval from oxytocin administration to the rupture of the chorioallantois (an embryonic membrane) as compared to Group 2. However, when the interval from oxytocin administration to delivery (OTDE) was more than 60 minutes, more foals were observed to be abnormal.

There were no differences in arterial blood gas values, vitality measurements, or cortisol levels among foals in the different groups. However, it was noted that a longer OTDE resulted in higher neonatal carbon dioxide (PaCO2) levels, and a longer time from oxytocin administration to chorioallantois rupture resulted in lower arterial pH in the foals. Both of these findings suggest distress in the newborn foals.

Processes relating to birth including degree of cervical dilation, premature placental separation or dystocia (difficult birth) impacted the health of the newborn foals. Foals born under adverse conditions took longer to stand and suckle than those born under normal circumstances.

Conclusions

The study concluded that the method of oxytocin-induced parturition did not significantly influence the health of the neonatal foals. However, the time from induction to parturition, degree of cervical dilation, and intrapartum complications all had an impact on the success of the induction.