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Failure to Thrive in Collie Dogs

Cyclic Hematopoiesis in Dogs

Cyclic hematopoiesis, a condition marked by recurrent episodes of blood cell formation, affects color-dilute gray collie puppies, often leading to frequent infections, failure to thrive, and premature death. Initially, the pups may seem healthy for the first 4–6 weeks before showing symptoms such as diarrhea, conjunctivitis, gingivitis, pneumonia, skin infections, joint pain, and fever. Intussusception of the small intestine is a common cause of death among affected puppies.

Episodes of illness, ranging from mild fever to severe infections, occur every 11 to 14 days. Gray pups are typically smaller and weaker than their littermates at birth, often being neglected by the mother.

Cyclic hematopoiesis has been identified in various collie bloodlines in the U.S. and other countries, but many experienced breeders avoid raising affected pups and may deny the presence of the responsible gene in their lineage. Consequently, gray collie puppies are not commonly seen.

In collie breeds, cyclic hematopoiesis primarily affects color-dilute pups, with the bone marrow disorder and color dilution being inherited as an autosomal recessive trait. This disorder can manifest as early as 1–2 weeks of age and is usually noticeable by 4–6 weeks. A similar condition has been observed in normal-colored pups in Border collie litters in the UK. While single cases have been reported in Pomeranians and cocker spaniels, the disease remains poorly characterized in these breeds.

Symptoms and Types

  • Diluted gray coat color
  • Being smaller and weaker compared to littermates
  • Weakness
  • Failure to thrive
  • Conjunctivitis, characterized by watery eyes and crusty discharge
  • Gingivitis, evidenced by reddened and/or swollen gums
  • Diarrhea
  • Pneumonia
  • Skin infections
  • Carpal joint pain, typically observed during the initial recovery phase of the disease cycle
  • Fever


The cause of this cellular disease is genetic inheritance.


For the diagnosis, it’s essential to provide a comprehensive history of your puppy’s health leading up to the appearance of symptoms. Any information regarding pregnancy, birth, and early stages of life will assist your veterinarian in determining the most appropriate steps. A thorough physical examination will be conducted, including blood chemical profile, complete blood count, electrolyte panel, and urinalysis.

If the complete blood count reveals consistently low levels of neutrophils at two-week intervals and the collie exhibits genetic expression for a dilute coat color along with nasal epithelial color dilution, this strongly supports a diagnosis of cyclic hematopoiesis.


The treatment plan involves supportive measures such as fluid therapy and antibiotics. While these interventions may prolong the lives of affected collie pups for several years, it’s essential to note that such treatments can be financially challenging.

There have been successful experimental treatments that disrupt the disease cycle, including bone marrow transplantation. Additionally, daily administration of endotoxin, lithium, or recombinant human or canine colony-stimulating factor has shown promise in managing the condition.

Living and Management

Unfortunately, sustaining the lives of puppies diagnosed with cyclic hematopoiesis entails significant financial expenses. Your veterinarian can update you on the latest experimental treatments available for this condition. However, for most owners, euthanasia may be the most practical option due to the high costs involved. If you own a color-dilute collie or a collie carrying color dilution genes (as evidenced by previous litters), it’s crucial to refrain from further breeding. This disease is hereditary and can be passed down through bloodlines, affecting both male and female collies.

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