Mare and foal survival and subsequent fertility of mares treated for uterine torsion.

This study investigates how surgical technique and stage of gestation affect mare and foal survival rates following uterine torsion, a common pregnancy condition in horses. The researchers concluded standing flank laparotomy is the preferred treatment, especially in early stages of gestation.

Background

• The primary focus of the study is uterine torsion, a common condition in pregnant mares (female horses), which can be life-threatening if not treated promptly.
• The authors aim to compare mare and foal survival rates between standing flank laparotomy and other surgical correction methods such as midline or flank laparotomy under general anesthesia, and correction per vaginam.

Methods

• The researchers performed a retrospective analysis of clinical records to gather their data.
• They analyzed data concerning 189 mares from three equine referral hospitals in The Netherlands that were treated for uterine torsion between 1987-2007.
• Factors such as the correction technique used, stage of gestation, degree of uterine rotation, animal survival, and subsequent fertility of the mares were considered in the study.

Findings

• The average stage of gestation at diagnosis was 283 days, with 77.5% of uterine torsions occurring before Day 320 of gestation.
• Following correction of uterine torsion, 90.5% of mares and 82.3% of foals survived until hospital discharge and through to foaling.
• Survival rates for both mares and foals were influenced by the stage of gestation and the correction method employed.
• Notably, foal survival rates were found to be significantly higher following a standing flank laparotomy, with a survival rate of 88.7%, compared to just 35.0% after other surgical techniques.
• Similarly, mare survival rates were also significantly higher when standing flank laparotomy was used during the earlier stages of gestation (before 320 days), with a survival rate of 97.1% compared to 50.0% for other techniques. However, no significant difference in mare survival rates was found between techniques when uterine torsion occurred in later stages of gestation.
• Of the sample, 123 mares were bred again after the procedure and 93.5% became pregnant. The fertility rates did not significantly differ with the surgical technique.

Conclusions

• The study concludes that the most effective surgical technique for correcting uncomplicated uterine torsion in horses is standing flank laparotomy, especially during the early stages of gestation (before Day 320).