The Pathophysiology of NI: Neonatal Isoerythrolysis is an immune-mediated haemolytic anaemia that occurs when a newborn foal inherits red blood cell antigens from its sire that are different from those of its dam. If the dam was sensitised during pregnancy or previous births, her colostrum will contain high titres of antibodies targeting the foal's erythrocytes, causing rapid intravascular and extravascular haemolysis once consumed.

Vigilant Colostrum Screening & Timing: Clinical symptoms typically manifest within the first 12 to 36 hours of life. If NI is suspected, muzzle the foal immediately to deny further access to maternal colostrum. Screen the foal's blood and test the dam's colostrum against the foal's red blood cells (such as via crossmatch or a lytic test) to verify active antibody matching. Provide an alternative source of secure, tested colostrum, and prepare for washed maternal erythrocyte transfusions if packed cell volume falls critically.

The Equine Corticosteroid Standard: Dexamethasone (IV) is the standard first-line choice during the acute stage, as horses cannot convert oral prednisone efficiently in the liver. Once stable and eating, they can be transitioned to oral Prednisolone.

When to use Dual Therapy (from Day 1): Initiate dual protocols (such as adding supportive low-dose heparin alongside IV dexamethasone) immediately if the horse shows active intravascular haemolysis, severe hypoxia, or sudden catastrophic drops in PCV.

When to use Sequential Therapy: If the patient presents with stable extravascular IMHA, starting with standard corticosteroid monotherapy is highly acceptable. Perform continuous digital pulse assessments and maintain laminitis monitoring.