Refinement

Refining animal experiments leads to less pain or distress. Evidence is growing that as well as benefiting the animals this helps the science.

Test cage for rats.

There are many different ways refinement can be achieved. Probably one of the best known examples of refinement was the banning of the LD50 test in 1999. That test sought to find the amount of a test chemical that would kill 50% of the animals being studied. By the time of the ban, more humane and milder options such as the Fixed Dose Procedure had become well established in British laboratories.

Modern imaging techniques mean a tumour growing in a rat for cancer research can be measured over time and the experiment stopped before the animal shows signs of distress.

Pain relief is given. In the past, based on common veterinary practice of the time, it was rare to give animals pain relief after an operation. That has all changed. Pain relief is not always the answer. In many cases it would be more distressing than the experiment itself so then pain relief is not given.

Refinement also refers to the way animals are housed and looked after. Much progress has been made to provide housing that reflects animals' natural desires. For example, rodents are given material to make nests and tubes to seek shelter in. Monkeys that would normally feed in the trees have taller cages so they can come to the ground and forage for food and then move higher to eat. They also have high level paths from one cage to another so that they can socialise. Dogs are housed with companionable partners.

Attention is now increasingly moving to the mental effects on animals, such as boredom, rather than the physical aspects alone. Animal technicians can train animals, such as dogs or monkeys, so that repeated dosages or blood sampling cause them less distress. Simply exposing young animals to complex environments as they grow up means they will be less nervous when it comes to being weighed or having their temperature taken in later life. Remote monitoring also provides a stress free method of finding out the effects a treatment might be having on an animal.