Age-related changes in hematologic and serum biochemical variables in dogs aged 16-60 days

The literature reporting hematologic and serum biochemical variables in puppies is limited. As puppies are physiologically different from adult dogs, an age effect would be expected.

We aimed to describe age-related changes in hematologic and serum biochemical variables in puppies aged 16-60 days and compare the results to reference intervals (RI) for adults. Our second aim was to determine RI for this age group.

A total of 227 blood samples were collected from 101 clinically healthy puppies, mainly mixed breeds. To assess the effect of age, the results were compared to RI for adult dogs, and variations within the age period 16-60 days were studied. Reference intervals for the groups 16-24, 28-45, and 46-60 days of age were determined.

Lower values in puppies compared to adults were found for RBC, HGB, HCT, concentration of albumin, globulin, total protein, creatinine, and sodium:potassium ratio. Higher values in puppies compared to adults were found for activities of ALP and CK, and concentrations of inorganic phosphorus, calcium, and potassium. For MCV, MCHC, albumin:globulin ratio, and glucose concentration, different values in puppies compared to adults were found for some of the age groups. No age-specific differences were found compared to RI for adults regarding WBC, absolute counts of lymphocytes, neutrophils, monocytes, eosinophils, and platelets, RDW, activities for AST, ALT, amylase, lipase, and concentrations of bile acids, cholesterol, urea, sodium, and chloride.

Our results support that age has a significant effect on several hematologic and serum biochemical values in puppies, warranting age-specific RI.