Emm, L., Heydon, J. 2022. The evolution of how guinea pigs are housed at high containment in the Biological Investigations Group. Animal Technology and Welfare 21(2), 137-140.

Previously, we housed guinea pigs in pairs, where study design allowed, using RC2R cages (NKP-Isotec). Our change was to house guinea pigs in bigger groups with more space. This resulted in moving the guinea pigs into a floor pen, which allowed them more space and to be housed into groups of 8. Although this floor pen was an improvement, it was impractical for Containment Level 3 (CL3). The final idea was to use our double tier caging system as we have used these previously at CL3 with different animal species. The system was first trialled with naïve guinea pigs within the directional airflow CL3 suite. The test trial of the guinea pigs in the double tier caging proved successful. Since then, we have completed two CL3 studies using this caging system. We have noticed the change of behaviour since they have been housed in these cages. In these cages at CL3, the maximum number of guinea pigs housed in one cage was 6. In these larger cages we were able to assess and health check animals more efficiently as we could see behaviours more clearly in the home cage rather than placing the guinea pig into a separate holding box – which can cause them stress. The animals have also shown more positive behaviours which suggest that they are happy; behaviours include ‘popcorning’ and vocalisations such as ‘wheeking’ – this is a high-pitched sound which denotes happiness and excitement. The study director analysed the weights of the guinea pigs in the different housing systems comparing the old caging to the new caging and plotted it on a graph. The data showed that the rate of growth of guinea pigs is the same in both the old and new caging system. However, the guinea pigs in the new caging are consistently lower in weight compared to those in the old caging system – this difference may be because the animals in the new caging system are getting more exercise and animal to animal interaction, due to more space in the new cage system compared to the older caging system.