摘要Background:The aims of this study were (a) to ascertain age-related changes in the reference values in hematological and serum biochemical examinations of beagles,and (b) to clarify the changes in these findings,including acute phase proteins and oxidative stress,throughout pregnancy and after parturition.Methods:Clinicopathological parameters were measured in young beagles at 6,9 and 12 months and in adult beagles aged from 24 to 60 months.Likewise,pregnant beagles were investigated throughout the pregnancy and after parturition.Results:Apparent age-related changes were found in erythrocytic parameters during the growth and development of beagles.Most of the parameters (total protein,albumin,blood urea nitrogen,creatinine,urate,alkaline phosphatase (ALP) and creatine kinase (CK） exhibited age-dependent transitions.White cell count significantly increased after 30 days of pregnancy.The values of erythrocytic parameters moderately decreased during the second half of the pregnancy.Triglycerides,total cholesterol,free cholesterol and phospholipid concentrations increased in the mid-and late stages of pregnancy.ALP,lactate dehydrogenase,CK and cholinesterase activities markedly increased during pregnancy and/or after parturition.C-reactive protein (CRP) concentrations gradually increased and reached a maximum after 30-40 days of pregnancy.Serum amyloid A (SAA) levels markedly increased at 30 days of pregnancy before subsiding,and then increased again 3 days after parturition.Reactive oxygen metabolites (d-ROMs) showed significant increases after 30 and 40 days of pregnancy.Conclusions:Reference values for hematological and serum biochemical examinations should be used for health evaluation of dogs,taking sex,age and the stage of pregnancy into consideration.Measurements of CRP,SAA and d-ROM levels are also useful for assessing maternal conditions in mid-pregnancy.