Training minipigs to participate in research procedures is both more safe, effective, and gentle for the minipig and for the people working with them. It enhances the minipig welfare because the minipigs are being stimulated.
Laboratory animals are subjected to different husbandry and/or research procedures. This could be small and easy procedures, like moving the animal from one place to another or more complex procedures that are not possible to do without either forcing the animal using fixation or anaesthesia or by training the animals to freely participate in the procedure.
The daily husbandry procedures should be recognized as an important part of the animals’ lives which means that it is as important to refine these procedures as the research procedures. Forcing animals against their will and without them knowing what is expected of them will often lead to confrontations between handler and animal and stress for both parties.
Clicker training
At Novo Nordisk we are working on letting the minipigs be able to predict and control its environment. This is done with a combination of habituation, socialization and actively training the minipigs. We train the minipigs using a method based on positive reinforcement training also called clicker training. Clicker training is a positive method of minipig training, where the trainer reinforces (rewards) a correct behaviour and ignores unwanted behaviour.
Clicker training is a very simple setup that can be used for all animal species. Most often the animals are trained with food and treats that they really like and therefore are willing to work to obtain. When using clicker training, the animals will initially learn to associate the click-sound with a reinforcer (bridging) and once this connection is established in the animal, the click-sound is used as a positive reinforcer to precisely signal to the animal when it is performing the desired behaviour and get the desired reinforcer.
A minipig that is clicker trained will participate in husbandry as well as research procedures because it knows that it will get a reinforcer afterwards. The minipig participates because it chooses to. It can also choose not to participate and success is therefore depended on a cooperation between minipig and human and that requires trust and connection. This makes it a very powerful training tool.
Training minipigs to participate in research procedures is both more safe, effective and gentle for the minipig and for the people working with them. It enhances the minipig welfare because the minipigs are being stimulated. Most minipigs find it fun to train. Negative stress is reduced, which is a refinement for the minipig and it is also beneficial for the scientific results since stress hormones can be a scientific confounder. Reduced stress levels and calmer minipigs in the experimental situation is also desirable to avoid mistakes, have more precise measurements (e.g. precise dosing), and to decrease the variability between each experiment. The time used on the experimental procedures is reduced and we can do experiments that we would otherwise not have been able to do, as the animal and the animal caretaker cooperate on the task. To train the minipigs and to handle well-trained minipigs add to job satisfaction for the animal caretakers and others working with minipigs. A positive relation – or bond – is built between the trainer and the minipigs.
New ways of training research animals
For many years, the animal caretakers at Novo Nordisk have been training dogs used in research. In 2017, an animal caretaker finished a certified dog trainer education. He was then appointed responsible training coordinator and put his experience and knowledge in system, which was then passed on to colleagues. At this time, we started experimenting with the use of clicker training for minipigs and the results were surprisingly good. In 2017, it was official decided from management that all research animals at Novo Nordisk should be trained for husbandry and research procedures as far as possible.
Several animal caretakers were sent on courses in positive reinforcement training of animals, which had a specific focus on research animals. It was new procedures for everyone and a lot was learned while doing it. We developed new ways of training the animals and we developed a system to register training performance. In the beginning, not everybody was equally excited about this new way of working with the animals, but slowly as the trainer’s knowledge and experience grew and the results started to speak for themselves, people were convinced that it is the right way to work with animals.
Reproduceable training system
When training research animals, we face challenges that are different from training companion or zoo animals. The animals have a limited time to learn the behavior since they are to participate in procedures shortly after arrival in the facility. Another challenge is that the animals will be trained by different trainers on different days. This caused us to develop a reproduceable training system and a reporting system that is easy to use and understand so that colleagues relatively easy can collaborate on the training of a group of animals. When working with minipigs, we are also favored by the fact that minipigs are very willing to train and they are curious and preceptive.
Today, most animal technicians at Novo Nordisk are responsible for training specific animals, from arrival to the end of the study. This means that they together with the scientist plan what should be trained, how and when, and they secure that colleagues can take over when they cannot train themselves. We also have a person who is functions as a training coordinator and is the overall responsible for training the animals.
No need for anaesthesia
Training minipigs have given us further advantages. We have been able to do some very complicated studies that would otherwise have been difficult or impossible to perform. An example of this is a study we are doing where a device given orally can be followed as it passes from the ventricle to the lower intestines without anaesthetizing the animals. The minipig is trained to walk up on a platform, where it will stand completely still (freeze) while an x-ray image is taken. The minipig leaves the platform and the next minipig walks up to have its x-ray taken. The minipig will then enter the platform again after five minutes. In this way, we can follow the device as it moves through the minipig, while the minipig is cooperating and having fun.
If the minipigs were not trained for the procedure, they would have had to be anaesthetized for half an hour during several days, which would have affected the research results to an extent that it could not have been done. It would also have been stressful for the minipigs and very time and manpower consuming. It takes us approximately 8 hours distributed over 3-4 weeks to train 8 minipigs for this procedure.
Repeated behaviour
Another example of a marked refinement in a study setup was a setup where we had to do measurements from the expiration air from the minipig. The normal way of taking these samples is to fixate the minipig and force a mask with an expiration bag over mouth and nose. The minipig is not easily fixated and will make a lot of noise scream during the procedure. Both minipigs and personnel are stressed and drained from energy afterwards.
We therefore decided to train the minipigs to voluntarily put their mouths and snout into the mask and then blow into the expiration bag. When we started training the minipigs, we only trained them to put their mouth and snout into the bag, hoping that we would be able to capture enough expiration air. We did not know that we would be able to train the minipigs to make a blow into the bag. But they quickly offered that behavior by themselves and all we had to do was to reinforce the behavior and then they repeated it. On study day, everything was calm in the stable while the samples were collected and the researcher got all their results with success.
Training minipigs to participate in husbandry and research procedures is rewarding both for the minipigs and animal technicians. It is a major refinement because it almost eliminates fixation and negative stress in the daily routines and during procedures.
It is our experience that it does not take long to train simple procedures and, for minipigs and dogs at least, it does not have to be the same person training the animal if there is a clear plan for the training and progress and shortcomings are communicated between the people training the minipigs. If the minipigs are in short term studies (few weeks), they will not be trained as much as minipigs that are here for a longer period, but we only use target training, luring and treats to move the minipig around and onto scales and strive to have as force free an environment as possible.
Luckily, to help us on our journey, our vendors of both farm pigs and Göttingen Minipigs are now starting the habituation and socialization from when the pigs are born.
This is a substantial contribution to our training and the pigs we receive are more curious and less anxious when we get them, and training can therefore begin 1-2 days after arrival.
We hope to be able to inspire others to train their research animals and are always open for questions and advice.
