AN INVESTIGATION INTO THE EFFECTS OF SOLID OR GRID CAGE FLOORING ON THE WELFARE OF LABORATORY RATS

The welfare of laboratory rats housed on either solid or grid floors w as investigated in several ways. No differences were found in body wei ght gain, food consumption or water consumption amongst rats housed in either condition. When handling was standardized between the 2 groups , there was no correlation between flooring and docility. Preference t esting revealed that rats chose to dwell on solid floors rather than g rids, regardless of previous housing experience. This preference for s olid floors was particularly marked (88%) when the animals were restin g and much less marked during activity (55.4%). Since the rats were ob served to spend 70 to 75% of their time resting, it was concluded that their welfare was likely to be improved by housing them on solid floo rs.