Neonatal Isoerythrolysis (NI): The ‘Fading Kitten’ Killer#

It is the most heartbreaking scenario in breeding. You have a litter of big, fat, healthy Maine Coon kittens. They nurse vigorously. Then, 24 hours later, they stop eating. Their urine turns dark brown (the color of port wine). Within hours, they are dead.

This is Neonatal Isoerythrolysis (NI). It wasn’t a virus. It wasn’t a bacteria. The kittens were poisoned by their own mother’s milk.

[cite_start]According to recent studies from the University of Pennsylvania cited in Robinson’s Genetics, the interplay between blood types is a primary cause of Fading Kitten Syndrome[cite: 1157].

The Blood Type Problem: A vs. B#

[cite_start]Cats have three blood types: A, B, and the very rare AB[cite: 1157].

• Type A: Most Maine Coons are Type A. (Note: “A” is dominant to “B”).
• Type B: Some Maine Coons (estimates vary from 2% to 5% in the breed) are Type B.

The Danger Zone: The problem occurs when you breed a Type B Queen to a Type A Male.

• The kittens will likely be Type A (carrying B).
• The Type B mother has naturally occurring, strong anti-A antibodies in her blood.

The “Poison” Colostrum#

When the kittens are born, they are healthy. However, the mother’s Colostrum (the first milk) is packed with her antibodies.

1. The Type A kitten nurses.
2. The mother’s anti-A antibodies enter the kitten’s gut.
3. [cite_start]For the first 16-24 hours, the kitten’s gut is “open” (permeable) to absorb these antibodies[cite: 2298].
4. The antibodies enter the kitten’s bloodstream and attack its Type A red blood cells.
5. The red blood cells burst (hemolysis). The kitten becomes anemic, jaundiced, and dies from oxygen deprivation and kidney failure (clogged by dead cell debris).

The Solution: The 18-Hour Rule#

If you have a Type B queen (which you should know via DNA testing), you CAN breed her to a Type A male, but you must intervene.

The Protocol:

1. Remove the kittens immediately at birth. Do not let them nurse even once.
2. Hand feed them with commercial kitten milk replacer (KMR) for the first 18 to 24 hours.
3. [cite_start]Gut Closure: After roughly 24 hours, the kitten’s intestines “close” and can no longer absorb the large antibody molecules[cite: 1157].
4. Reunite: You can put the kittens back on the mother. Her milk still contains the antibodies, but they will now pass harmlessly through the kitten’s digestion without entering the bloodstream.

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Conclusion#

NI is completely preventable. In the modern era of breeding, losing a kitten to blood type incompatibility is a failure of husbandry. Test your queens. If she is Type B, be ready with the bottle.

References#

1. Vella, C. et al. (1999). Robinson’s Genetics for Cat Breeders and Veterinarians. “Blood Types,” p. [cite_start]183. [cite: 1157]
2. Pedersen, N.C. (1991). Feline Husbandry. “Reproduction and Reproductive Disorders,” p. [cite_start]129. [cite: 2303]
3. Giger, U. (University of Pennsylvania). Feline Blood Groups and Incompatibility.
4. CFA. Feline Health: Neonatal Isoerythrolysis.
5. Little, S. (DVM). Pediatrics: The Fading Kitten.
6. Casal, M.L. et al. (1996). “Feline colostrum and milk antibodies.” American Journal of Veterinary Research.
7. Walsh, L.G. (2013). [cite_start]The Maine Coon Cat. [cite: 1164]