A Case Study on the Behavioural Effect of Positive Reinforcement Training in a Novel Task Participation Test in Göttingen Mini Pigs

Abstract

In laboratory animal research, many procedures will be stressful for the animals, as they are forced to participate. Training animals to cooperate using clicker training (CT) or luring (LU) may reduce stress levels, and thereby increase animal welfare. In zoo animals, aquarium animals, and pets, CT is used to train animals to cooperate during medical procedures, whereas in experimental research, LU seem to be the preferred training method. This descriptive case study aims to present the behaviour of CT and LU pigs in a potentially fear-evoking behavioural test-the novel task participation test-in which the pigs walked a short runway on a novel walking surface. All eight pigs voluntarily participated, and only one LU pig showed body stretching combined with lack of tail wagging indicating reduced welfare. All CT pigs and one LU pig displayed tail wagging during the test, indicating a positive mental state. Hence, training pigs to cooperate during experimental procedures resulted in a smooth completion of the task with no signs of fear or anxiety in seven out of eight animals. We suggest that training laboratory pigs prior to experimental procedures or tests should be done to ensure low stress levels.

Keywords: clicker training; laboratory pigs; positive reinforcement training; welfare.

Figure 1

Variables assessed during the task (i.e., walking across the three plastic-coated plastic turf mats). Each individual pig is presented. Median and IQR (interquartile range) is shown on all four figures. (a) The time (seconds) it took each pig to complete the task. (b) The number of reinforcers the trainer used during the task. (c) Tail wagging during the task shown as percent of time spent tail wagging. (d). Body stretching. The number of body stretches shown by each pig during the task is shown. LU: luring, CT: Clicker training.