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Johns Hopkins Bloomberg School of Public HealthCAAT

Animal Welfare Enhancement Awards - 2005 Recipients

Effects of Cage Size and Enrichment on Rodent Behavior and Cardiovascular Function
Tara Burke and Anora Burwell
 University of Arizona

We believe that standard housing conditions for laboratory rodents are inadequate in terms of both size and enrichment. These standard conditions may cause a stress response that could adversely affect the physiology and psychology of the animals and, consequently, any scientific data derived from them. It is our hypothesis that rats housed in larger, more enriched cages (as compared to the standard condition) will be less stressed, as determined by several behavioral and cardiovascular parameters. We will measure and compare these parameters from rats pair-housed in four different conditions: 1) standard-sized cage with no enrichment; 2) larger-sized cage with no enrichment; 3) standard-sized cage enriched with a PVC tunnel, and 4) larger-sized cage with a PVC tunnel. All data will be compared to condition 1, which is the current standard used in animal facilities. Three pairs of rats will be rotated through all four housing conditions, for a period of four weeks in each condition, until they have experienced all conditions twice. One rat in each pair will have been implanted with a radiotelemetry transmitter that allows for noninvasive measurement of cardiovascular parameters. During collection of telemetry data (both during the day and at night), the rats will be videotaped and their behavior will be evaluated for signs of psychological stress. We hope to demonstrate that enhancing the housing conditions of laboratory animals will reduce the physiological and psychological effects of stress and thus improve the welfare of animals used for research.