Blood Sampling in Göttingen Minipigs-A Case Study of Two Standard Methods and Clicker Training as a Restraint-Free Alternative.

Blood sampling often requires restraint that negatively affects animal welfare. This case study evaluated three methods for jugular vein blood sampling (V-bench, sling, and clicker training) with the overall aim of assessing the negative impact on animal welfare and providing a general recommendation on the use of methods. First, the effects of simulated blood sampling in V-bench and sling on behaviour, heart rate, and saliva cortisol concentrations 15 min after sampling were assessed. The sling (which had the least negative effects) was re-evaluated after one week of habituation to assess a possible positive effect. Clicker training was evaluated using behavioural observations only. The heart rate was significantly higher in animals placed in the V-bench compared to the sling (p < 0.05), but no significant differences were found in the saliva cortisol concentrations. Habituation to the sling resulted in a further reduction in heart rate compared to the V-bench (p < 0.01). When trained to voluntarily cooperate, three out of six minipigs allowed blood sampling from the jugular vein without restraint. We are convinced that all six minipigs would have succeeded if the training environment had been optimised. In conclusion, clicker training results in blood sampling with no negative behaviours displayed such as struggling or squealing/screaming. When restraint is unavoidable, the sling is preferable compared to the V-bench.