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Failure to Thrive in Collie Dogs

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Cyclic Hematopoiesis in Dogs


Cyclic hematopoiesis (formation of blood cells) in color-dilute gray collie pups is characterized by frequent episodes of infection with failure to thrive and early death. Clinically, the pups may appear normal for the first 4–6 weeks and then develop diarrhea, conjunctivitis, gingivitis, pneumonia, skin infections, carpal joint pain, and fever. A frequent cause of death of the pups is intussusception (blockage) of the small intestine.


Episodes of illness, varying from inactivity accompanied by fever, to life-threatening infection, repeat at 11- to 14-day intervals. The gray pups are usually smaller than their litter mates at birth, weak, and often pushed aside by the bitch.


Cyclic hematopoiesis has been observed in many collie bloodlines in the U.S. and in other countries; however, experienced collie breeders do not attempt to raise the affected pups and frequently will not acknowledge the presence of the responsible gene in their bloodline. As a result, gray collie pups are not commonly observed.


Cyclic hematopoiesis in the collie breed is present only in the color-dilute pups. The color dilution and bone marrow disorder are inherited as an autosomal recessive trait (presumably the same gene). The bone marrow disorder and color dilution was present in pups resulting from a collie/beagle cross and could occur in any mongrel with collie bloodlines in both parents, if both parents had the recessive gene. Clinical signs occur as early as 1–2 weeks of age and are always apparent by 4–6 weeks of age.


An apparently similar disease was reported in normal-colored pups in two Border collie litters in the UK. Single cases of cyclic hematopoiesis have been reported in Pomeranians and cocker spaniels; the disease is not well characterized in these breeds.


Symptoms and Types


  • Coat color is diluted gray
  • Smaller and weaker than litter mates
  • Weakness
  • Failure to thrive
  • Conjunctivitis, may be symptomized by watery eyes, crusted discharge on eyes
  • Gingivitis, symptomized by reddened and/or swollen gums
  • Diarrhea
  • Pneumonia
  • Skin infections
  • Carpal joint pain, observed during the initial recovery phase of the disease cycle
  • Fever




This cellular disease is inherited genetically.





You will need to provide a thorough history of your puppy's health leading up to the onset of symptoms. Any details that you can provide about the pregnancy, birth, and infancy stages will be helpful for your veterinarian in determining the appropriate course of action. Your veterinarian will perform a complete physical exam on the puppy, including a blood chemical profile, a complete blood count, an electrolyte panel, and a urinalysis.


If the complete blood count shows an abnormally low number of neutrophils at two week intervals, and the collie shows expression of genes for a dilute coat color along with a nasal epithelial color dilution, this is strong support for a diagnosis of cyclic hematopoiesis.



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