Are investigators aware of environmental noise in animal facilities and that this noise may affect experimental data?

Control of environmental factors, such as noise, in animal facilities is important to ensure that research animals respond consistently to experimental procedures and that experimental results are not confounded by outside influences. A survey of personnel involved with animal facilities (173 respondents) showed that almost all agreed with this statement. However, 48% thought that one or more environmental factors in their facilities could be stressing the animals, and a majority of respondents reported generation of audible noise from people (72% of respondents), fans (61%), and squeaky carts (56%). The presence of these noises was correlated with the perception of noise as a problem because of its psychologic and physiologic effects on the animals. The amount of time respondents spent in the facilities was strongly correlated with their perception of noise as a problem, with veterinarians spending the most time and perceiving the most problems, and professors and assistant/ associate professors spending the least and perceiving the fewest. Therefore, they may lack key knowledge that can affect their research goals. In addition, because faculty are the least aware of noise as a potential problem but are primarily responsible for designing experiments, research involving animals may be confounded by noise as an unknown variable. This effect may lead to unnecessary numbers of animals being required to achieve statistical significance and possibly to erroneous interpretation of results. On the basis of the findings of this survey, we present recommendations for improving the environment, particularly for decreasing the noise level, in animal facilities.