The pathogenesis of dystocia and fetal malformation in the horse.

The research paper focuses on understanding the causes of severe birth difficulties and fetal malformations in horses, examining different presentations during birth and how they relate to these issues.

Study Overview

The study analyzed 601 cases of severe dystocia (difficult births) in mares, or female horses. Three types of presentations were identified during birth:

• Anterior presentation (fetus is facing forward, which is the ideal position for birth): This accounted for 408 cases (68% of the total).
• Posterior presentation (fetus is facing backwards, which can make birth more difficult): This represented 95 cases (16% of the total).
• Transverse presentation (fetus is positioned horizontally, which makes a normal birth almost impossible): This made up 98 cases (16% of the total).

Distortions and malformations were also noted.

Findings and Interpretations

Among the cases with anterior presentation, 37% showed reflected heads and necks. For those with posterior presentation, it was observed:

• 50% presented hip flexions
• 25% had hock flexions
• 25% had stretched hind legs
• 47% of the fetuses were in lateral or ventral position
• 30% of the fetuses were malformed, primarily showing torticollis (twisted neck) and head scoliosis (curvature of the spine)

As for the transverse cases, all were complete or partial bicornual pregnancies (pregnancies where the fetus develops in both uterine horns) with 35% malformed fetuses, most common being wryneck (a neck deformity that twists the head to one side).

Conclusion

The evidence gathered led to the conclusion that in mares, the posterior and transverse presentations are significant causes of fetal malformation and of dystocia. The researchers also assessed the effectiveness of different obstetrical methods – repositioning, embryotomy (surgical removal of a dead fetus), and Caesarian section – in managing these cases. The exact results for each method, however, were not mentioned in the abstract. This conclusion reinforces the importance of pre-birth monitoring and appropriate intervention plans in preventing complications associated with these presentations.