Effect of Age, Sex, and Breed on the Blood Biochemistry and Physiological Constants of Dogs From 4 Weeks to > 52 Weeks of Age.

Abstract

Background: Blood biochemistry and reference intervals help to differentiate between healthy and ill patients as well as to provide information for the prognosis, evaluation, and monitoring of a patient; however, these intervals are often obtained from adult animals. It is essential, hence, to understand that puppies and adults are physiologically different, which justifies the need to obtain age-specific biochemical reference intervals. The aim of this research was to assess the potential effect of age, sex, breed, and interaction on routine biochemical analytes and physiological constants (body temperature, heart rate, and respiratory rate) in addition to establish age-specific reference intervals. In order to carry out the research, we selected 197 healthy dogs of different sex and breed classified by age: group I (4-8 wk), group II (9-24 wk), group III (25-52 wk), and group IV (>52 wk). The biochemical analysis measured the enzymatic activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and concentration of cholesterol, triglycerides, total proteins, albumin, globulins, glucose, urea, and creatinine. Statistical analyses used the Analysis of Variance (ANOVA) and General Linear Model (GLM), which allows the comparison of multiple factors at two or more levels (p < 0.05). Results: The results of this study showed that ALT, total protein, albumin, globulin, urea, creatinine, and body temperature levels were lower in puppies compared to adult dogs (p < 0.05) while the enzymatic activity of ALP, LDH, glucose concentration, and heart rate were higher. Moreover, in small breeds, the serum creatinine levels were lower (p < 0.05) whereas sex and interaction did not show a significant effect (p > 0.05).Conclusions: Some biochemical components evince influence by age. For this reason, this research offers specific reference intervals to help the veterinary clinician to interpret the biochemical results of puppies with accuracy.