Most US laboratories must adhere to two main sets of animal welfare regulations. The laws are passed by congress to establish broad rules and goals; then agencies within the executive branch provide detailed instructions on how to follow them.
The Animal Welfare Act of 1966 (AWA), with the associated Animal Welfare Act Regulations (AWAR; see Title 9 of the Code of Federal Regulations or Animal Care from the USDA), defines standards and requirements.
The Health Research Extension Act of 1985 provides the legislative mandate for the Public Health Service Policy on Humane Care and Use of Laboratory Animals (referred to hereafter as "the PHS Policy")
The Animal and Plant Health Inspection Service (APHIS) of the USDA oversees enforcement of the AWA, which also regulates zoos, exhibitors, animal dealers, and those who transport animals in commerce.
The AWA covers the care of research animals and includes guidelines for the oversight and conduct of studies intended to minimize or prevent pain or distress in laboratory animals. It regulates all warm-blooded species except for domestic mice and rats bred for scientific purposes and farm animals used in agricultural research.
Provisions for veterinary care have existed under the AWA since 1970. In 1985, requirements were added for exercising dogs and for ensuring the psychological well-being of nonhuman primates. Guidelines for birds were introduced in 2023; however, birds bred for research are excluded from the AWA.
Enforcement of the AWA is via self-reporting, along with unannounced inspections by APHIS. Failure to meet requirements can result in fines, citations, criminal proceedings, or revoked registration and disqualification from using AWA-regulated species in research.
The PHS Policy relies on the Guide for the Care and Use of Laboratory Animals (referred to hereafter as The Guide), a set of research animal care standards first issued in 1963. Institutions are required to use The Guide as a basis for developing and implementing animal care and use programs for animals used in research. The PHS Policy has been modified only once, in 2002. The Guide, now in its 8th edition, was last revised in 2011.
The 220 pages of The Guide are organized into five chapters covering the following subject areas:
key defining concepts, including applicability, a brief review of the ethical principles in the humane care and use of animals in research, and clarifying definitions
articulation of the basics of animal care and use program—most prominently, oversight structure, all aspects of safety, and requirements for research and animal care training
the environment, housing, and management of research animals
veterinary care
animal research facility design and physical plant operation
Within the context of The Guide, the attending veterinarian (AV) was conferred unquestionable responsibility for the welfare of any animal in research, including at all times during experimentation, in all phases of the animal's life, and with the authority to prescribe treatment or require euthanasia.
In 2024, the Office of Laboratory Animal Welfare (OLAW) began public engagement for potential revisions to the PHS Policy, emphasizing updated expectations with respect to transparency, protocol review flexibility, and harmonization with other international standards.
The PHS Policy applies to all research institutions awarded federal grants—in excess of $35 billion in 2023 from the National Institutes of Health (NIH) alone. The policy covers all vertebrate animals, not just those that are warm-blooded.
Regulatory compliance with the PHS Policy is based on a system of self-regulation whereby institutions must provide to federal officials 1) a written Animal Welfare Assurance statement describing their compliance with the PHS Policy, 2) updates via an annual report, 3) timely reporting of deficiencies, and 4) access for site visits.
Failure to adhere to the PHS Policy can result in revocation of federal funding for some or all research projects at a given institution.
In addition to federal animal welfare regulations, several US states and municipalities maintain their own oversight systems. Some states have laboratory animal welfare laws that require licensing, inspections, or local registration with an Institutional Animal Care and Use Committee (IACUC). Some cities impose additional requirements via public health or institutional review mechanisms, particularly when local funding or public facilities are involved.
At an international level, the Global Animal Law Association (GAL) provides a database for animal welfare legislation in various continents and countries around the world. Global legislation mainly prescribes engineering standards—measurable requirements such as cage floor area, change frequency, temperature/humidity ranges, and air changes per hour. Standards and enforcement vary widely, hindering harmonization. In contrast, nonbinding guidelines emphasize performance standards (eg, sanitation outcomes) that can be adopted across jurisdictions (1, 2). Directive 2010/63/EU is legislation to protect animals used for scientific research in all European Union countries.
Program Accreditation for Animal Research Programs
AAALAC International, incorporated in 1965, is a private nonprofit organization that promotes the humane treatment of animals in the valid conduct of science. This is a voluntary accreditation and assessment program. To date, more than 1,140 companies, universities, hospitals, government agencies, and other research institutions in 52 countries/regions have voluntarily earned AAALAC accreditation.
Institutions that seek AAALAC accreditation are subject to comprehensive peer review of their animal care and use programs every 3 years. This accreditation is recognized by the NIH as compliance with the PHS Policy.
In 2023, AAALAC released a new position statement—The Attending Veterinarian, Veterinary Team, and Provision of Veterinary Care—emphasizing the essential role of veterinarians in overseeing programs.
In 2024, AAALAC introduced the option of hybrid site visits for eligible programs, enabling a combination of virtual and in-person assessments. Hybrid site visits were developed and successfully introduced during the SARS-CoV-2 pandemic to accommodate participants' social distancing and health and safety. These visits consist of videoconferencing and electronic document sharing for an initial remote program assessment, followed by a required on-site animal facility review.
The accreditation for agricultural programs has expanded substantially, with the introduction of new resources and webinars in May 2025 to support institutions using farm animals under the 2020 Guide for the Care and Use of Agricultural Animals in Research and Teaching.
Veterinary Care of Laboratory Animals
Every licensed and registered facility is required by the AWA to define a written program of veterinary care (PVC) that includes full- or part-time employment of an attending veterinarian (AV). The PVC must explicitly address access to diagnostic laboratory services, including after-hours and emergency availability, as part of the institutional responsibility for veterinary support.
AVs are required to have some training in laboratory animal medicine. Many institutions hire veterinarians board-certified by the American College of Laboratory Animal Medicine; however, small institutions that might have only a few animals for teaching purposes often contract with a local veterinarian (3).
The responsibilities of the AV and the requirements of the associated PVC were derived from a blend of sources, most prominently the AWAR and The Guide. Under provisions of the AWAR, everyone who uses animals in research, exhibits animals, sells them at the wholesale level, or transports them in commerce must have an established PVC.
The AV (as well as any veterinarian designated by the AV) is responsible for the well-being and clinical care of all animals used in research, testing, teaching, and production at all times and during all phases of life. The AV also has the authority to treat laboratory animals, to remove animals from an experiment, and to take appropriate measures, including euthanasia, to relieve severe pain or distress for any animal.
A key requisite for laboratory animal care is that the AV must balance the experiment's goals with knowledge of the research animal model systems in use, including side effects and potential complications. If the AV is not a full-time employee, the PVC must detail the scheduled frequency of visits by the AV, identify the channels of communication with the AV, and address the availability of veterinary services at all times.
Guidance from AAALAC International in 2024 emphasized the need for AVs to help develop humane end points and adverse event criteria in protocols, especially for high-risk studies or novel procedures.
The AV is responsible for reviewing a facility's PVC at least once a year to ensure that it continues to conform with the standards of veterinary care for each species. As of this writing, increased emphasis is placed on documenting the AV's review of all procedures involving surgical interventions, novel substances, or genetically modified animal models, with written justifications included in IACUC records.
Whatever the employment arrangement is, the AV must have authority to ensure adequate veterinary care across facilities, personnel, equipment, and services to satisfy a broad array of requirements. These requirements include but are not limited to the following:
legal procurement
acclimation and quarantine
proper housing, husbandry, nutrition, and provisions for exercise
daily health checks and reporting
disease and injury prevention, surveillance, and response
nutrition
emergency care
safe and appropriate use of pesticides
for wild or exotic animals, capture and restraint methods
Together with the IACUC (see below), the AV contributes expertise in defining the optimal conditions of social and environmental enrichment for each species. In addition, the AV provides guidance for the care of animals—including handling, immobilization, anesthesia, sedation, tranquilization, pain management, pre- and postprocedural care, and euthanasia—and participates in training personnel who care for or use animals.
Jointly with an IACUC, the AV is responsible for overseeing surgery programs and ensuring that surgeons who create animal models are suitably qualified and trained in the procedures, including aseptic technique.
Institutions are also encouraged to maintain logs of continuing education and competency reassessments for AVs and veterinary staff, especially for species-specific or high-containment work in accordance with AAALAC's 2023 recommendations.
Institutional Laboratory Animal Care and Use Committees
Scientists who are preparing a protocol are required by the AWA to consult with a veterinarian if the subjects might experience more than momentary or slight pain or distress. Protocols may be reviewed by a quorum of the IACUC at a meeting (full committee review) or by a subset of IACUC members (designated member review).
Each IACUC, as authorized and guided by the AWA and the PHS Policy, oversees all aspects of the care and use of animals in research at a given institution and serves as a critical instrument in safeguarding the public trust.
According to the AWA, an IACUC must consist of at a minimum of five voting members. It must include at least one veterinarian with training in laboratory animal science and expertise with the species used in experiments, at least one practicing research scientist, and at least one person not affiliated with the research institution. The PHS Policy also adds a nonscientist to the list.
Because research regulations and guidance are stated in general terms and allow for professional judgment, their interpretation and evaluation depends critically on IACUCs. For these reasons, as well as the large scale of some institutions, IACUCs often include more than the minimum number of members to broaden their expertise into different scientific areas, such as ethics, jurisprudence, library science, biostatistics, and safety.
Each IACUC has three main areas of responsibility:
review of research protocols
regular evaluations of the institution's animal care and use, including applicable programs (eg, veterinary care), and semiannual inspections of animal housing areas and surgeries
judicature, which includes investigating animal welfare concerns, addressing unacceptable protocol deviations, and adjudication (eg, when protocols are ambiguous and are interpreted differently by the AV and the scientist)
The Institutional Official, the person with institutional authority and means to ensure the effectiveness of the IACUC, receives reports of these activities.
An IACUC reviews a research protocol by considering the merits of the animal study in the context of a broad range of complex scientific, animal welfare, and veterinary topics. Assessment includes evaluating the likelihood that the value of the knowledge or improvements in human and/or animal well-being resulting from the research will exceed anything untoward experienced by the animal subjects.
The AWA requires scientists who are preparing a protocol to consult with a veterinarian if subjects of the protocol might experience more than momentary or slight pain or distress. Categories for pain and distress are clearly defined in the AWA, and the role of the veterinarian is crucial in determining appropriate anesthesia and analgesia. Protocols may be reviewed by a quorum of the IACUC at a convened meeting, which is termed (full committee review), or by delegation to a subset of IACUC members outside of a meeting, defined as (designated member review).
IACUCs explicitly review protocols for considerations of replacement alternatives and inclusion of objective end points, particularly for studies with prolonged or progressive animal models. At the time of this writing, institutions are encouraged to include retrospective protocol reviews to assess actual animal outcomes versus predictions, as part of ongoing quality improvement.
IACUCs also have the responsibility of monitoring the compliance of ongoing studies and the authority to suspend research that does not comply with the conditions of approval or that has unforeseen negative consequences. In 2024, guidance from the NIH emphasized determining cause in cases of protocol noncompliance or unexpected animal outcomes, to support institutional learning and improvements.
Protocols expire at 3 years and, if continued, are renewed as a de novo creation. Within the 3-year period, protocols may be modified by the same full committee or designated member review processes or via veterinary verification and consultation. The latter allows the IACUC to entrust a qualified veterinarian to review certain minor changes, such as those related to anesthesia, euthanasia methods, and therapeutic drugs.
Emergency Preparedness for Animal Research Programs
History shows that the enormous national investments in animals, equipment, experiments, and animal research facility structures are unpredictably subject to the effects of natural events, human-caused disasters, or technology failures.
The Guide requires each institution to maintain and continually reassess a comprehensive emergency operations and disaster responsiveness plan to promote resilience and prevent, absorb, recover from, and adapt to adverse events. These written plans are required to include contingencies to evacuate or depopulate the full census of laboratory animals.
Although an emergency preparedness plan is a living document, subject to continued evaluation and revision, it is only one component in the cycle of preparation, mitigation, response, and recovery associated with disasters and emergencies.
Structural and program resilience begins with design and construction that incorporate fail-safe mechanisms and redundancy (eg, emergency power). Program resilience continues with preventive maintenance and worksite and personnel preparedness, including drills and tabletop exercises. The most successful approach to emergency preparedness is to focus on coping with interruptions in function, most commonly utility disruptions and personnel shortages.
To protect the knowledge and economic hubs involved in research, the plan for a specific animal research program should be integrated into the parent institution's larger plan and then linked with private and public community partners and stakeholders up to the federal level.
For More Information
Mohan S, Huneke R. The role of IACUCs in responsible animal research. ILAR J. 2019;60:43-49. doi:10.1093/ilar/ilz016
Petervary N, Pullium JK. Disaster planning and research continuity in responsible animal research. ILAR J. 2019;60:74-85. doi:10.1093/ilar/ily023
Lerat H, Delis P, Bussell J, Gonin P. Pandemic preparedness in animal facilities. J Am Assoc Lab Anim Sci. 2021;60:244-248. doi:10.30802/AALAS-JAALAS-20-000104
References
Rowlands DK, Guillen J. The use of performance-based outcomes in achieving better global harmonisation in the care and use of animals in research. Lab Anim. 2025;59:120-127. doi:10.1177/00236772241309745
Bayne K, Turner PV. Animal welfare standards and international collaborations. ILAR J. 2019;60:86-94. doi:10.1093/ilar/ily024
Hedenqvist P, Baumans V, Hanai K, et al. Toward global harmonization of training and certification of specialists in laboratory animal veterinary medicine. J Am Assoc Lab Anim Sci. 2022;61:15-20. doi:10.30802/AALAS-JAALAS-21-000044
