Research Communications of the 24th ECVIM-CA Congress

Authors are affiliated with genetic disease screening test laboratory. Remarkably little has been published on haematological and serum biochemical phenotypes of the domestic dog. Information on the signalment and complete blood cell count of all dogs with normal red and white blood cell parameters judged by existing reference intervals was extracted from a veterinary database; similar information was collected from all dogs with normal serum biochemical profiles, considering all parameters other than glucose as inclusion criteria. Normal haematological profiles were available for 6046 dogs, 5447 of which also had machine platelet concentrations within the reference interval; normal serum biochemical profiles were available from 3045 dogs, 1495 of which also had accompanying normal serum glucose concentrations. For the haematological data, 75 pure breeds plus a mixed breed control group were represented by 10 or more dogs, while for the serum biochemical data, 60 pure breeds plus a mixed breed control group were represented by 10 or more individuals. All measured haematological parameters except mean corpuscular haemoglobin concentration (MCHC), and all serum biochemical analytes except sodium, chloride and glucose, varied with age. Concentrations of white blood cells (WBCs), neutrophils, monocytes, lymphocytes, eosinophils and platelets, but not red blood cell parameters, all varied with sex, as did total protein, globulin, potassium, chloride, creatinine, cholesterol, total bilirubin, and activities of alanine aminotransferase (ALT), creatine kinase (CK), amylase and lipase. Neutering status had an impact on haemoglobin concentration, mean corpuscular haemoglobin (MCH), MCHC, and concentrations of WBCs, neutrophils, monocytes, lymphocytes and platelets, as well as all serum biochemical analytes except albumin, sodium, calcium, urea and glucose. Principal component analysis (PCA) of haematological data revealed 37 pure breeds with distinctive phenotypes, while PCA of serum biochemical data revealed over 50 pure breeds with distinctive phenotypes. Furthermore, all haematological parameters except MCHC and all serum biochemical analytes except urea and glucose showed significant differences between specific individual breeds and the mixed breed group. Twenty-nine breeds had distinctive haematological phenotypes and 21 breeds had distinctive serum biochemical phenotypes when assessed in this way. Tentative breed-specific reference intervals were generated for breeds with a distinctive phenotype identified by comparative analysis. This study represents the first large-scale analysis of haematological and serum biochemical phenotypes in the dog and underlines the important potential of this species in the elucidation of genetic determinants of haematological and biochemical traits, triangulating phenotype, breed and genetic predisposition, as well as the urgent need for breed-specific reference intervals in clinical practice.