Methods which improve animal welfare

Our goals are to ensure that each individual animal within an experiment is experiencing the minimum pain, suffering, distress or lasting harm that is compatible with a meaningful result. Both direct harms (such as pain following an injection) and associated harms (such as altering a social group to equalise experimental group sizes) need to be considered.

Any departure from normal conditions, routine and treatment could contribute to the overall impact of the procedure on the animal. The duration of an experiment is also considered. Examples of refinement include using the least invasive methods for any surgery with appropriate anaesthetics and analgesics, and placing limits on the number of times an individual animal may experience a particular stress. The Babraham Campus Animal Usage Guidelines are reviewed regularly by vets and the AWERB ethical review committee. These advise on certain procedures such as dosage routes, volumes and frequencies, and follow a variety of published good practice guidelines.

The ultimate aim is the continual improvement of an experimental model with the minimal departure from normality. Advance consideration of any likely adverse events, such as a drug reaction or an infection, together with definition of humane end points is essential.



  • Mice are routinely handled using the cupping technique. When mice are transferred between cages this is carried out using hands, or rafts that are present within the cage, as opposed to picking up by the tail.
  • The default method to collect tissue samples to confirm the genetic make-up of mice was changed from using the tail tip to the ear. Welfare advantages include a lack of sensitivity in the ear and its limited functionality compared to the tail tip.
  • Use of the latest technologies in monitoring animal welfare, such as using assessments of lung function in respiratory infection studies, to improve our ability to detect issues at an earlier stage and therefore maintain high levels of welfare.
  • Environmental enrichment is compulsory in animal cages and is varied to suit the occupants. For example, refuges such as opaque tunnels and elevated rafts are provided, the latter also being of value in case of drinking water leaks.
  • Food treats such as seeds may be mixed in bedding to provide interest and all animals are provided with materials to build nests.
  • Design innovations by a facility manager created the Cell Pad device, which is now internationally distributed as in-cage environmental enrichment, as well as being used in the Institute’s facility.
  • Procedure-success monitoring informs technician training and ensures that techniques are performed to a high accuracy.
  • Use of heat-pads during embryo transfer surgery to avoid risk of hypothermia.