The 3Rs – Refinement

Refinement means improving how animals are cared for and treated during research. This includes reducing pain and stress, providing better living conditions, and adapting procedures to suit the animals’ individual needs. Improving animal welfare not only benefits the animals themselves but also leads to better‑quality research that is more reliable and consistent. 

Improved handling techniques 

Using low-stress handling methods such as cupping and tubing instead of lifting by the tail reduces anxiety and stress. Regular interactions using these handling techniques allow rodents to become familiar with handlers, which is important for calmer cage changing, health checks, and experimental procedures.

Rat enrichments and rehoming 

Animals have access to a rat play pen designed and developed to encourage social interaction, play, and other natural behaviours. Some of our rat caging is modified to provide additional floorspace on different levels, using suspended tubes, and a link between cages via a plastic tube. This link between cages allows rats to socialise and play while still retaining their own safe space.

Other cage modifications have been made to allow male rats who have fathered a litter to be separated within the same cage allowing him to smell and see the female and pups. Usually, male fathers would be completely separated from the female and pups.

Mouse cage enrichment 

All our mouse cages, unless specified otherwise for the conditions of experiments, contain many items to provide enrichment for the mice under our care. As standard we include: 

• Sawdust bedding which absorbs urine to keep the cage dry 
• Sizzle nest – a densely folded paper material used for nesting. 
• Cocoons – small cotton rolls which allow mice to use their natural shredding instincts to create nesting material. 
• Chew sticks which promote chewing to allow mice to wear down their continuously growing incisor teeth. 
• Sunflower seeds or wheat grains which encourage foraging behaviours and are small food treats. 
• A plastic or cardboard mouse house to provide a safe space and a nesting area. 
• A plastic tube on the cage floor to provide a haven and a climbing opportunity. Red plastic is typically used to provide rodents with security through reduced visibility, but it also allows care staff to check the animals. 
• Plastic tube tied to the food hopper to increase overall available floor space, encourage climbing behaviours, and provide a secure space. 

 In addition to the tube attached to the food hopper we have attached cable ties to cage lids creating swings to encourage natural play behaviours. 

DIY forage balls are a popular foraging activity, especially with ex-breeder male mice. These are constructed using sterilised toilet roll tubes which are cut into strips to form a ball with sunflower seeds and/or wheat grains hidden within sizzle nest. 

For mice on study that cannot be supplied with sunflower seeds due to potential impacts on experimental results, we supply wheat grains to encourage natural foraging behaviours. These wheat grains have the same ingredients as our standard rodent diet meaning they have no potential impact upon experimental outcomes.  

Refinement of procedures 

Voluntary administration of substances 

Wherever possible, animals are given substances or medicines voluntarily, mixed with a palatable liquid or semi-solid substance. This avoids more stressful methods such as oral gavage, where a tube is passed down the oesophagus and into the stomach.  

Voluntary dosing is used for drug studies, metabolic tests, and some infection studies, and is less stressful for both animals and staff.  

Monitoring animal welfare using scoring systems 

Barbering or hair plucking can happen in mice when there is stress or disruption to their social environment. We have developed a scoring system to closely monitor affected animals and to define a humane endpoint. This standardises prompt intervention to minimise adverse welfare. 

Special scoring systems are also used for genetically altered mouse models to spot early signs of a change to normal health caused by the introduced genetic mutation.  

Animal care staff use these systems to identify welfare concerns at the earliest possible opportunity to reduce the risk of adverse welfare for individual animals. 

For specific disease models, tailored scoring systems help animal care staff and researchers clearly understand when humane endpoints have been reached, ensuring animals do not suffer unnecessarily. 

Blood sampling 

Blood samples are taken without restraining the animals whenever possible, which helps reduce stress for both the animals and the staff involved. 

Researchers use the smallest blood sample volumes possible to obtain reliable results. Ongoing improvements in laboratory methods at the University of Dundee have helped further reduce the amount of blood needed for many metabolic and drug discovery related studies. 

When larger blood samples are needed over a longer time period, especially in rats, animals are given treats as positive reinforcement to help reduce stress and make the process more comfortable. 

Staff training and a culture of care 

Everyone involved in animal research at the University of Dundee receives regular training on animal welfare, behaviour, and contemporaneous best practices. 

A strong culture of care is encouraged, where staff feel comfortable raising welfare concerns, sharing ideas, and working together to continuously improve how animals are cared for