PREFERENCES OF MICE AND RATS FOR TYPES OF BEDDING MATERIAL

The type of bedding material has been reported to affect the environme nt in both the animal cage and animal room. It has an impact on the he alth and well-being of the animals and may cause biased experimental r esults. Requirements for bedding materials, particularly those regardi ng animal comfort are poorly supported by experimental data. In this s tudy, various types of bedding material were evaluated using preferenc e tests with mice and rats. It was found that beddings consisting of r elatively small particles (less than or equal to 1.2 x 1.6 mm(2)) wee generally avoided, whereas beddings consisting of large fibrous partic les were preferred. The characteristics of the bedding materials were further investigated by scanning the size and shape of the particles, and by the assessment of ultrasound produced by the moving of the bedd ings. The results seem to indicate that size and manipulability are am ong the main determinants of the appreciation of bedding particles by laboratory mice and rats, and larger particles are preferred.