Use of score sheets for welfare assessment of transgenic mice

The use of transgenic mice has increased dramatically in recent years and continues to increase further. However, because transgenesis may alter a balanced genotype and produce unpredictable effects, careful monitoring of health and welfare of the transgenic animal is advised. The present study assessed the feasibility of the use of score sheets for monitoring transgenic mice, as part of daily routine, in a transgenic unit. The score sheets used were based on parameters which are sensitive and easy to determine. The score sheets were used by two animal technicians and a thorough evaluation showed that the score sheets, as described in this paper, are useful for routine monitoring in a transgenic unit and may result in the early detection of animal welfare problems. However, notwithstanding the limited number of parameters included and the restricted age-span covered by the screening, the monitoring system was considered to be time consuming. Large-scale implementation of such a scoring system during the first weeks of life would increase daily care time by at least 15-20 min for an average litter of 4-6 pups. Nevertheless, the use of score sheets seems to be a prerequisite for monitoring the animal's welfare in the course of producing transgenic lines.