Neonatal isoerythrolysis

Symptoms include lethargy, weakness, depression, pale mucous membranes, fever, and blood in the urine.

If there is a blood-type mismatch, the kittens should not be allowed to nurse for 72 hours from the mother to prevent the passage of antibodies in the colostrum.

It is a medical emergency and requires immediate veterinary attention to prevent further decline in health and subsequent death.

Horses, unlike humans, have an epitheliochorial placenta which prevents the transfer of antibodies to the foal in-utero.

However, a few factors, such as Aa and Qa, do lead to a significant response and therefore account for the majority of cases of isoerythrolysis.

Immune mediated thrombocytopenia often occurs concurrently in mule foals suffering from neonatal isoerythrolysis.

A definitive diagnosis can only be made if alloantibodies are discovered in the mare's serum or colostrum and are shown to be against the foal's red blood cells.

Such tests include crossmatching the mare's serum to washed red blood cells of the foal, which is added to exogenous complement, and is positive if hemolysis occurs.

[2] The severity of clinical signs and their speed of onset is determined by the dose of alloantibodies taken in by the foal and their potency.

Mares with multiple exposures to a blood group antigen also produce a greater amount of alloantibodies and therefore the foal receives a larger dose.

The mare should be stripped of milk and the foal muzzled during the time to prevent additional ingestion of colostrum.

Foals are supported with fluids, which are used to maintain hydration, correct electrolyte and acid-base imbalances, and help perfuse the stressed kidneys which can be damaged by the circulating hemoglobin.

[2] Prognosis depends on the amount of alloantibody received and their potency, which may be indirectly measured by the degree of clinical signs.

In this case, all subsequent foals should be given an alternative source of colostrum unless the mare is blood typed and bred to a compatible stallion.

[2] In breeds most commonly associated with this disease, such as Thoroughbreds and Arabians, compatible stallions that fit with the goals of the breeder's program may be difficult to find.

Blood groups that have been associated with NI, such as Ab, De, Ua, and Pa, are generally not used in risk assessment of mares.