Clinical and hematological effects of serial phlebotomy performed on laboratory beagles

We conducted a study designed to mimic a typical pharmacokinetic study to gain a better understanding of a dog's response to multiple, frequent blood sampling at 15% total blood volume. Ten dogs were randomly assigned to either a control group having sham venipuncture performed or to a blood collection group having 1.5% of their body weight (approximately 15% total blood volume) removed weekly for 4 weeks. Both groups were monitored during a 2-week recovery period immediately after the 4-week collection period. Parameters evaluated were clinical signs, body weight, and hematological and serum biochemical analytes. There were minimal differences in red blood cell morphology between the two groups. Statistically significant differences in hematocrit between the two groups occurred on several days, and this finding was attributed to blood withdrawal in the blood collection group; however, this statistical difference was not deemed to be clinically significant. There were no statistically significant differences in body weight, total protein, reticulocyte count, mean corpuscular volume, mean corpuscular hemoglobin, or red cell distribution width. We conclude that removing 15% blood volume in laboratory beagles is compatible with maintaining the health and well-being of the dog and can be acceptable in laboratory situations when it is scientifically justified.