Noise produced by vacuuming exceeds the hearing thresholds of C57Bl/6 and CD1 mice

Daily vacuuming of floors and flat-shelf racks is a standard procedure in our rodent housing rooms. To determine whether the noise produced by this activity is a potential stressor to animals used for transgenic and knockout mouse production, we measured the sound levels in our genetically engineered mouse facility under ambient conditions and at the in-cage and room levels during vacuuming. Spectral analysis showed that vacuuming produces a multitonal, low-frequency noise that is not attenuated by microisolation caging with bedding material. Comparison of cage-level spectral analysis results with age-specific audiograms of C57Bl/6 and CD1 mice showed that vacuuming produces frequencies audible to C57Bl/6 mice at 3 and 6 mo of age and to CD1 mice at 1 mo of age. These findings suggest that vacuuming in animal rooms could be a source of stress to animals with these genetic backgrounds.