Two related cases of cerebellar abnormality in equine fetuses associated with hydrops of fetal membranes.

This research presents two unique cases of brain defects in horse fetuses, coupled with a rare pregnancy complication known as hydrops allantois, in which there is excessive accumulation of fluid in the allantoic cavity of pregnant mares.

Overview of the Cases

• Two pregnant Haflinger mares experienced extreme abdominal expansion and were identified having hydrops allantois. Both mares were seven months pregnant.
• To handle the pregnancies, abortion was induced using prostaglandin injections, additional cervix dilation, and using oxytocin.

Findings

• The allantoic cavities of the mares held large amounts of fluid (90 and 95 litres), which had similar characteristics as extracellular fluid in terms of urea, creatinine, sodium, potassium, calcium, magnesium, phosphate, and chloride concentrations. However, total protein concentration was not comparable.
• Severe brain abnormalities were discovered in both fetuses. These were diagnosed as hypoplasia (underdevelopment) of the cerebrum and cerebellum, internal hydrocephalus (the buildup of fluid in the cavities or ventricles deep within the brain), hydranencephaly (a condition in which the brain’s cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid), and complete absence (aplasia) of the cerebellum. Each fetus displayed a slightly unique pattern of abnormalities suggesting a common cause with varied manifestations.

Implications

• Despite the pregnancy abnormalities occurring in mares impregnated by the same stallion, there was no explicit connection to a genetic cause. This can lead to further studies to understand if these cases were an anomaly or if there is an unknown environmental factor influencing the development of cerebellar abnormalities in equine fetuses in combination with hydrops allantois.

In conclusion, this research illustrates a complex and rare combination of brain defects in equine fetuses, linked with hydrops allantois condition during pregnancies. The lack of an apparent hereditary link implies that other unidentified factors might be in play, opening up avenues for further investigation.