Neonatal isoerythrolysis in horse foals and a mule foal: 18 cases (1988-2003).

This research article investigates the clinical features, data, and outcomes from horse and mule foals suffering from neonatal isoerythrolysis (NI) – a disorder involving a blood type incompatibility between the mare and foal causing serious illness after consuming her colostrum, by examining 18 cases over a period of 15 years.

Study Methodology

• The researchers conducted a retrospective case series study including 17 horse and 1 mule foals.
• The foals studied were all less than 14 days old showing signs of NI.
• Data collected from records included the animal’s species and age, examination findings, the relevant blood, serum and plasma biochemical parameters, treatments given, and outcomes.

Key Findings

• When evaluating data for foals with an average age of 71 hours, it was observed that many had high serum indirect and direct bilirubin concentrations and sorbitol dehydrogenase activity, indicating possible liver issues.
• Whole blood immunoglobulin concentrations were below the normal range in 4 out of 15 foals, suggesting inadequate passive transfer of colostral antibodies.
• Among 11 foals, a blood factor Dg, not previously associated with NI, was implicated in the condition.
• Life-saving whole blood transfusions were given to 10 out of 18 foals. Seven of the ten showed significant improvements in hematocrit (Hct) and hemoglobin concentration, and two showed significant improvements in central venous oxygen tension, improving tissue oxygenation.

Conclusions and Future Implications

• The presence of blood factor Dg may be associated with NI in foals; this finding may be helpful for future screenings and prevention methods.
• The study suggests there may be concurrent liver disease in foals with NI.Diagnosis and proper treatment of these associated conditions could further improve the prognosis for these foals.
• The potential for NI to develop in foals with inadequate passive transfer of colostral antibodies has implications for breeding management, including the crucial need for adequate colostrum intake after birth.
• Whole blood transfusions were found to improve oxygen-carrying capacity and peripheral tissue oxygenation and can be considered a successful treatment method.
• Despite the severity of NI, with appropriate treatment the prognosis for foals is positive – 15 out of 18 foals survived to discharge.