Benefits for animals – a neglected part of the animal research debate

By Nuno Franco

The ethics of animal research are usually framed as animal harms versus human benefits. But what changes when animals are used, at least in part, for the sake of other animals?

It is often said, in discussions around animal research, that although such research is mainly aimed at improving human health and welfare, animals may also benefit from it. However, this is taken at face value without solid grounding on verifiable information. Moreover, the ethical implications raised by animals being used in research to benefit other animals are hardly addressed in the literature. While this opinion piece does not intend to fill these gaps, it will hopefully provide some factual information for a better framing of the issue, while pointing to unresolved ethical matters that are currently underexplored.

The most immediately recognisable animal benefit of regulated procedures arises in education, particularly in the training of veterinary professionals and biomedical researchers, with distinctions between the two cohorts with regard to both the animals used and those who may potentially benefit from it in the future. In the case of veterinary education, one can confidently claim that using animals to train vet students in diagnostic techniques, drug administration or surgery will result in the improvement of the health and welfare of many more, in the future. Moreover, if animals bred for veterinary training are kept under strict welfare standards, they can live long lives under high welfare standards. A Refinement/Reduction balance must however be struck regarding how many vet students can perform a given procedure (e.g. rectal palpation in a cow) until the cumulative impact on each animal’s welfare exceeds what is ethically admissible.

The use of animals for training researchers to perform experimental procedures can also be framed as beneficial to future animals, but only in the sense that it makes researchers perform such procedures competently and with the utmost respect for animal welfare. However, while the severity of the procedures later carried out by researchers might be reduced, with direct benefits to the animals undergoing said procedures, in most cases both the animals used for training researchers and those later used in research will be killed.

Regarding the use itself of animals for scientific purposes, a direct future benefit for animals from a particular animal experiment is difficult to ascertain, similarly to the case of animal research for human benefit. Regarding the latter, however, high-profile discoveries can be traced back to the animal studies leading up to them. These might in some cases amount to hundreds of studies over the course of decades (See Eggel and Grimm (2018) [1] for a discussion on these and other matters regarding estimation of benefits from animal research). Importantly, some animal studies may contribute more than others. A recent example is Karikó and Weissman’s work on nucleoside-modified mRNA in mice, which enabled mRNA COVID-19 vaccines and helped save an estimated 20 million human lives in the first year of vaccination alone. [2,3] It is important to note, however, that such work was built on decades of research which also included animals, but was not, in its early stages, deemed novel or impactful enough [4], highlighting the importance of fundamental research.

While such high-profile cases are rare in veterinary medicine, direct benefits from research on animals in this field can also be confidently ascertained, given that the establishment of mechanistic principles in pre-clinical studies and subsequent target-animal studies (i.e. in the same species the therapies being tested are aimed to benefit, e.g. dogs, cats or pigs) provide the grounding for the development, authorisation, and clinical use of veterinary medicines. However, preclinical research on veterinary drugs may often be hidden in statistical reports within the broad category of “regulatory use”, and not be distinguishable from that carried out for human drugs, except of course those carried out on target-species, which in 2023 only included 4,295 animals, for EU27+Norway (source: ALURES database [5]). In any case, and at least for these animals, one can point out an intention to directly benefit animals of the same species, with benefits for other animals expected to be manifold.

The EU Regulation 2019/6 on veterinary medicinal products clearly demands pre-clinical studies for establishing the pharmacokinetics and pharmacodynamics of drugs for use in veterinary medicine. Interestingly, in said Regulation pre-clinical studies are not described as requiring animals, though in most cases they certainly do so, but rather as studies “required to establish the pharmacological activity and the tolerance of the product”, providing a model-agnostic regulatory framework. Whether this was an intentional future-proofing of the legislation or a fortunate consequence of ambiguous legal writing, it can provide a framework for an easier transition to non-animal alternatives, at the regulatory level, as they become available.

Despite this regulatory openness to using replacements to animal experiments for the development and testing of veterinary drugs, said replacement seems to still be incipient, judging from EMA’s 2025 3Rs Working Party Biennial report (2023/2024) [6] and its 2025 Reflection Paper on implementing the 3Rs for regulatory testing of medicines [7]. And indeed, the European Medicines Agency (EMA) regulatory information on the ethical use of animals for testing veterinary medicines refers to Directive 2010/63/EU, linking directly animal research to veterinary drug development (see https://www.ema.europa.eu/en/human-regulatory-overview/research-development/ethical-use-animals-medicine-testing).

Direct evidence of procedures being carried out in animals for the sake of (other) animals can be taken from official European Union statistics provided by the European Commission on the ALURES platform. [5] The categories “protection of the natural environment in the interests of human or animal health or welfare”; “preservation of species”; “ethology, animal behaviour, and animal biology”; “animal diseases and disorders”; and “animal welfare”, in 2023, comprised the use of 2,147,417 animals for EU27 and Norway, representing 26.6% of all animals used in procedures, that year (Fig.1). And while we have observed since 2021 a modest yet steady drop in the number of animals used under Directive 2010/63/EU, the proportion of animal use reported under animal-oriented categories has remained steadily high (>26%) (Fig. 2).

This large proportion of animal use reported under animal-oriented purposes is surprising, but calls for cautious interpretation. Firstly, ALURES reports purposes and uses, not realised outcomes. A study reported to be carried out under “Animal Welfare” may nonetheless fail to improve animal welfare in any way, a project on animal disease may generate weak or inconclusive evidence, and a study of animal behaviour may contribute to scientific knowledge without having any direct application. What one can more defensibly claim is that a substantial proportion of regulated animal use is officially reported under purposes plausibly connected to animal biology, animal health, animal welfare, species preservation, or environmental protection. Nonetheless, European legislation does not only contemplate intended human benefits but also intended benefits to animals and the environment as part of the ethical and regulatory landscape. This, in and of itself, should reframe the classical ethical discussion around animal research.

The ALURES figures are also likely to underestimate the wider amount of animal research being carried out oriented to benefit animals (and likewise for that aimed at benefitting humans). Directive 2010/63/EU defines a procedure as any intervention “which may cause the animal a level of pain, suffering, distress or lasting harm equivalent to, or higher than, that caused by the introduction of a needle in accordance with good veterinary practice”. It hence excludes practices below that threshold. It also excludes non-experimental clinical veterinary practice and veterinary clinical trials required for the marketing authorisation of veterinary medicinal products. As a result, much research relevant to animal welfare, animal behaviour, husbandry, conservation, veterinary diagnosis, and clinical treatment may fall outside the Directive’s reporting scope. Observational studies, non-invasive behavioural work, field monitoring, routine clinical investigations, and some veterinary clinical activities may therefore contribute to animal health or welfare without being accounted for in ALURES figures.

Environmental protection is also of key importance. The protection of ecosystems, control of wildlife disease, preservation of threatened species, and monitoring of environmental harms are the epitome of a One Health perspective, defined by the World Health Organisation as an integrated approach that seeks to balance and optimise the health of people, animals, and ecosystems, recognising that these are closely linked and interdependent. [8] Research reported under environmental protection or species preservation may therefore have several beneficiaries: humans, domestic animals, wildlife, and ecosystems.

It should also be noted that animal research for the benefit of humans may also eventually benefit animals. Human and veterinary medicine have overlapping histories, methods, and disease concepts, and comparative medicine has long connected the two domains. [9] Hence, research originally aimed at improving human health can later provide valuable treatments to veterinary medicine, as well as advanced diagnostics, new surgery techniques, and improved anaesthesia and analgesia, to say a few. The benefits can also go in the opposite direction, for example with regard to veterinary vaccine research, which not only has contributed to the control of animal and zoonotic diseases, but has also spearheaded methodologies that led to advancements in human vaccinology. [10] Moreover, broadening vaccination efforts, in terms of target species and pathogens, also contributes to preventing bacterial resistance to antibiotics, which also aligns with the One Health concept.

While the existence of animal-oriented research might introduce changes to the ethical framework under which animal research is morally considered, it does not solve any of its ethical caveats. If, on one hand, many scientific questions about animal disease, welfare, behaviour, conservation, or ecology cannot yet be answered without using animals in ways that may cause harm, on the other hand the individual animals used in those procedures often do not benefit from the research. They may not even be of the species expected to benefit. Modelling leishmaniosis infection in mice, for instance, may be ethically justified by its potential benefits to dogs, wildlife, livestock, or humans, but that possible future benefit does not remove the immediate harm to the mice being used.

Considering benefits to animals makes the dilemma posed by animal research more complex, as it adds to the classical “animal harms vs. human benefits” tension an additional one between “animal harms vs. (other) animals’ benefits”. This might be particularly morally ambiguous to those who oppose animal research, but may understandably also want to have safe and effective vaccines and therapies for their own animals. And while Directive 2010/63/EU addresses this tension to some extent by demanding project evaluation to include a harm-benefit analysis to decide on whether harms imposed on experimental animals are offset by potential benefits to “humans, animals, or the environment”, the specific ethical issues raised by “animal research for animals” remain underexplored. And while such issues remain unresolved, acknowledging their idiosyncratic nature would be a first step in proposing distinct approaches to ease the moral and regulatory challenges at hand. For example, the intended animal benefit could only be considered in a harm-benefit analysis when the beneficiary species and the harmed species are named in advance and a plausible mechanism of transfer is stated. Future discussions should include under what conditions such research is justified (e.g. regulatory framework, adherence to the 3Rs, medical and scientific priorities, etc.), how relevant and likely the expected benefit must be, how directly it must relate to the animals used, and how much harm can be ethically admissible to be imposed on one group of animals for the possible benefit of another.