From 29 animals per batch to 17: how vet vaccine testing quietly changed
What happened
Every batch of veterinary vaccine made in the UK has to be checked before it can be used. For decades, a lot of that checking involved animals. A sample of the batch would be given to animals to confirm it was safe and that it worked. Figures published on 24 September 2026 by the Veterinary Medicines Directorate, part of the Department for Environment, Food and Rural Affairs, show how much that has changed over twelve years. The number of animals used per vaccine batch fell by 41%, from 29 animals in 2013 to 17 in 2024. Overall animal use fell by 29%, and that is despite more vaccine batches being released over the same period. So the total went down while output went up. The proportion of vaccines that need any animal testing at all fell from 74% in 2013 to 34% in 2024. And several species have dropped out of routine batch testing altogether: horses, cats, dogs, turkeys and pigeons. Baroness Hayman, Minister for Biosecurity and Trade, said: 'Better science means we can reduce animal testing, while still giving farmers, vets and pet owners the vaccines they rely on.' Abi Seager, Chief Executive of the VMD, described the report as showing 'twelve years of sustained, measurable progress in reducing animal testing within the veterinary medicines industry.'
Why this matters
Most people have a simple instinct about animal testing: less of it is better. The difficulty has always been that vaccines protect animals too. A badly made batch of clostridial vaccine can kill a flock of sheep. What this report describes is not a trade-off but a genuine improvement on both sides. Fewer animals used, and the same safety checks. The biggest single change came early. In 2013 the routine Target Animal Batch Safety Test was removed. That test involved giving a sample of every batch to the species it was meant for, simply to confirm nothing had gone wrong in manufacturing. Years of data had shown it almost never found anything that other checks missed. Dropping it saved thousands of animals a year. Since then the gains have come from laboratory alternatives: cell-based tests, chemical assays and better analytical methods that can confirm a vaccine contains what it should, in the amount it should, without an animal. There is a wider point here about how regulation improves. Nobody made a dramatic announcement in 2013. A test was quietly removed once the evidence said it was not earning its place. Twelve years of that adds up to a 41% reduction.
What the evidence actually says
It is worth reading the figures carefully. The headline 41% is animals per batch. The 29% is total animals. Those differ because more batches are being produced, so the per-batch fall is steeper than the total fall. Both numbers are honest; they measure different things. The report also does not claim the job is finished. Two categories of vaccine still require animal testing, and the VMD says so plainly: clostridial vaccines, used heavily in sheep and cattle, and fish vaccines used in aquaculture. The reasons are technical. For clostridial vaccines, potency has traditionally been measured by whether the vaccine protects against a toxin, and replacing that with a laboratory test that reliably predicts real-world protection has proved difficult. Fish vaccines face their own problems, partly because fish immune systems differ from mammals and partly because the alternatives are less developed. So this is progress with a clearly stated remainder, which is more credible than a claim of total success. One more caveat: these figures cover batch release testing of veterinary vaccines in the UK. They are not a measure of all animal research, or of testing done overseas on products later sold here.
Practical advice
If you own animals, none of this changes what you should do. Vaccinating pets and livestock remains one of the clearest cases where the benefit heavily outweighs the risk, and UK batch testing is if anything more rigorous now than it was. If animal welfare in testing matters to you, the useful thing to know is that the framework is called the 3Rs: Replacement, Reduction and Refinement. The UK's National Centre for the 3Rs, NC3Rs, publishes its work openly and is a better source than most campaigning material on either side. If you are a farmer, the clostridial vaccines that still require animal testing are also among the most valuable in British livestock farming. That tension is real, and it is being worked on rather than ignored. If you want to check something specific about a veterinary medicine, the VMD maintains a public Product Information Database listing every authorised product in the UK. And if you are choosing between brands on welfare grounds, be aware that batch release testing requirements are set by the regulator, not the manufacturer, so they are largely the same across products of the same type.
What to know
UK figures published on 24 September 2026 show animals used per veterinary vaccine batch fell 41% between 2013 and 2024, from 29 to 17. Total animal use fell 29% even though more batches were released, and the share of vaccines needing any animal testing dropped from 74% to 34%. Horses, cats, dogs, turkeys and pigeons are no longer needed for routine batch testing. Clostridial and fish vaccines still are, for technical reasons the regulator sets out openly. Most of this came from removing one routine test in 2013 once the evidence showed it added little, and then twelve years of steady replacement with laboratory methods. It is a good example of regulation improving quietly rather than dramatically. Sources: Department for Environment, Food & Rural Affairs and Veterinary Medicines Directorate, 'Animal use in veterinary vaccines quality control falls to lowest levels in a decade', 24 September 2026, https://www.gov.uk/government/news/animal-use-in-veterinary-vaccines-quality-control-falls-to-lowest-levels-in-a-decade ; Veterinary Medicines Directorate, https://www.gov.uk/government/organisations/veterinary-medicines-directorate ; National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), https://www.nc3rs.org.uk/ This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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