Areas we study

The types of animal research carried out at the university range from:

1. Fundamental biology

Fundamental biological and medical research helps us to identify key physiological mechanisms that control how our bodies work, effect health and disease and that could lead to medical breakthroughs in the future

2. Veterinary

To identify and develop ways of assessing welfare in order to influence standards of care in farms and improve care of sick animals, such as developing better pain relief in pet dogs with arthritis.

3. Translational

To develop better treatments for sick people or animals, such as implanting and testing new medical devices in farm species.

The types of studies our animals may be involved in include blood tests, behavioural studies and imaging. Other studies might involve surgery to implant monitoring devices that measure changes in the body, or new medical devices that could help save human lives.

Animals used in research

In 2022, the University carried out scientific procedures on 25,428 animals in research regulated by the Animals (Scientific Procedures) Act 1986. The vast majority of these involved rodents (56.2%) and fish (42.2%).

SpeciesNumber of animalsUse
Mouse 7,618  2,470  1,429  7  1,223 Rodents play a vital role in helping us to answer a wide range of questions, including understanding fundamental aspects of our physiology, our genetic pathways and the mechanisms of disease that support the development of future medicines and treatments for both humans and animals.
Rat 9  472  863  1  193
Zebrafish 10,221  111  374  20  5 Zebrafish allow us to model the effects of cardiovascular disease, cancer and osteoarthritis as well as to study the genetic changes that can contribute to these debilitating diseases. They are incredibly good at regenerating cells, tissues and organs, something that we cannot do. By studying how they are able to do this we hope to find better ways of treating people in the future.
Bat * 0  202  0  0  0 We study bats to assist with their conservation. Understanding their genetics could help us work out how we can protect them from the effects of global warming.
Pig 0  0  79  0  35 Pigs and sheep can help us develop new treatments and devices to benefit both human and animal health. Pigs are also used in studies of infectious disease to develop new vaccines for humans and better medicines for farm species in the future.
Sheep 0  0  20  0  5
Guinea pig 0  52  0  0  0 Guinea pigs are used as a source of tissues for the study of aspects of physiology that are important for improving patient treatment.
Rabbit 0  0  0  0  19 Rabbits are the most suitable species for our researchers to study important aspects of cardiac physiology that are key to improving our understanding and in the long-term patient treatment.


* These procedures involved wild caught animals which were then released at the end of the study.

Understanding Severity

All regulated procedures carried out under ASPA are assigned a severity to help evaluate the potential harms vs. benefits of the scientific work. The overall experience of each animal is then assessed at the end of a study and reported annually:

  • Sub-Threshold – 70.2% - These are animals which have not suffered any level of pain or distress as a result of the studies, and have lived a life akin to that of a pet animal.
  • Mild – 13.0% - These are animals which have experienced no more than short-term mild pain, suffering or distress. Examples of mild procedures are the injection of a drug with no lasting harmful effects, or undertaking behavioural studies including preference tests or reward-based tasks.
  •  Moderate – 10.9% - These are animals which have experienced no more than short-term moderate pain, suffering or distress or long-lasting mild pain, suffering or distress. This may be a surgical procedure; animals recovering from surgery are always provided with pain relief medication similar to those prescribed in a veterinary practice.
  • Severe – 0.1% - These are animals which have experienced no more than short-term severe pain, suffering or distress, or long-lasting moderate pain, suffering or distress.
  • Non-Recovery – 5.8% - These are animals which have experienced no more than being placed under a general anaesthetic before the start of the procedure then are humanely killed without ever regaining consciousness.

Understanding our zebrafish and mice numbers

In 2022, the breeding of genetically altered (GA) animals accounted for 95% of our scientific procedures using zebrafish and 48% using mice. Breeding of GA animals is regulated under UK law and is therefore counted like a scientific procedure.

GA animals are important because specific changes in their genetic make-up enable researchers to discover and understand relationships between genes, physiology, and disease.

Some of our research that benefits from the breeding of GA animals includes cancer, immunology, cardiology, osteoarthritis and human genetic disorders.

Complex breeding cycles across multiple generations are essential to create these new GA animals before they can be used in a scientific study.

Find out more about the breeding of genetically altered animals on the Understanding Animal Research website.

Procedures on zebrafish

‌‌Pie chart showing 95% of scientific procedures using zebrafish in 2022 were related to the breeding of genetically altered and 5% experimental

Procedures on mice

‌‌Pie chart showing 48% of scientific procedures using mice in 2022 were related to the breeding of genetically altered and 52% experimental

Previous years

Facts about animal research

  • All animal research in the UK is regulated and inspected by the Home Office.
  • It is illegal in the UK and Europe to use animals in research if an alternative approach is available.
  • It is illegal in the UK and Europe to use animals to test cosmetics or their ingredients.
  • It is a legal requirement that all potential new medicines intended for human use are tested in two species of mammal before they are given to human volunteers in clinical trials.
  • The law states that all potential veterinary medicines must be safely tested in animals.
Image credit: University of Bristol
Image credit: University of Bristol
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