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

## TL;DR

This study compares methods for blood sampling in minipigs, finding that clicker training and the sling method reduce stress and improve animal welfare.

## Contribution

The study introduces clicker training as a restraint-free alternative for blood sampling in minipigs.

## Key findings

- Clicker training enabled three minipigs to voluntarily cooperate during blood sampling without restraint.
- The sling method caused fewer negative effects compared to the V-bench, especially after habituation.
- Heart rate was significantly higher in the V-bench compared to the sling method.

## Abstract

This study focuses on minimising stress and discomfort in laboratory minipigs during blood sampling procedures. We assessed three methods for jugular vein blood sampling: two methods that require restraint (the V-bench and the sling), and clicker training, where the pigs are trained to voluntarily cooperate during the procedure. The goal was to evaluate how these methods impact animal welfare and recommend the best approach. The study examined the effects of simulated blood sampling in the V-bench and the sling on behaviour, heart rate, and saliva cortisol levels 15 min after sampling. Overall, the sling method showed fewer negative effects on the animals compared to the V-bench. Clicker training allowed three animals to voluntarily cooperate; however, we firmly believe all six could have succeeded in a better training setup. In summary, clicker training results in blood sampling with no negative behaviours such as struggling or squealing/screaming. When restraint is unavoidable, the sling is a better alternative to the V-bench. By identifying methods that allow animals to voluntarily cooperate, a higher standard for animal care is made available, improving both the lives of animals and the quality of data obtained for scientific and medical purposes.

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.