Electromyographic properties of the myometrium correlated with the endocrinology of the pre-partum and post-partum periods and parturition in pony mares.

The research focuses on studying the electromagnetic properties of the myometrium (muscle layer of the uterus) in pony mares, especially during the days leading up to and after childbirth. It identifies distinct patterns of electromagnetic activity during these periods, which may help understanding aspects of equine reproduction.

Study Design and Data Collection

• The research involved making a combination of electromyographic (EMG) records, taking plasma samples, and noting behavioral observations of two pony mares.
• The study started seven days before parturition (childbirth), continued through it, and also covered the early postpartum period.

EMG Activity Prepartum

• In the week leading up to parturition, there was an increase in EMG activity. It was recorded happening between 26 to 73% of the time.
• The activity was lesser during the daytime and higher at night. However, there was no significant difference noted either throughout the day or between days in this prepartum phase.

EMG Activity Around Parturition

• In the 24 hours just before the actual delivery, EMG activity increased 55-80% of the time during daylight hours, persisting for about 7 to 13 hours.
• Just before the foal’s delivery, this activity dropped for about 2 to 4 hours. There was a sudden increase in EMG activity at the time of rupturing of the chorioallantois (part of the fetus’s placenta).
• During the very act of delivery, the recorded EMG activity comprised roughly 10 to 13 distinct bursts of increasing strength, coming one after the other rapidly.

Postpartum EMG Activity

• After the foal’s delivery, there was a noticeable reduction in EMG activity until the placenta was delivered. Subsequently, there were very long (ranging from 2 to 22 minutes) trains of electrical potentials observed.

Ideal Application of Findings

• The behavioral and electromyographic findings in the mares suggest that monitoring EMG activity could play a crucial role in predicting and managing equine reproduction health.