Objective: Familiarizing an animal to the procedure is necessary for accurate measurement of blood pressure (BP). However, this requirementconsiderably prolongs the procedure, which in some instances could add to spurious results. There is, therefore, a need to establish ways that willhelp reduce stress and minimize the duration required for BP measurements in conscious animals. This study therefore examined the effect of thepresence of a littermate on the duration to achieve the first acceptable blood BP measurement using tail-cuff plethysmography in naïve conscious rats.Methods: BP was measured in 12-weeks old, in-house naïve male Sprague-Dawley rats, either without prior familiarization and without a littermateor after familiarization for 15 minutes, but without a littermate or after familiarization and with a naïve male littermate or without familiarization butwith a naïve male littermate or without familiarization but with a naïve female littermate. Time to the first accepted measurement was recorded. Datawere analyzed using one-way ANOVA and post-hoc analysis.Results: The duration to the first acceptable BP measurement in familiarized and naïve rats was significantly shorter in the presence of a malelittermate (p<0.001), but not with a female littermate when compared with that in naïve rats without acclimatization or the presence of a littermate.Conclusion: It appears that the presence of a male littermate when measuring BP in naïve male rats significantly decreases the duration required forthe measurement of BP. This might improve the efficiency of the procedure and even produce better data.Keywords: Familiarization, Littermate, Tail-cuff rat, Blood pressure
