Sarah graduated from Cambridge in 1981 and remained a partner in general practice until 2018 where she worked for several years, also taking on the role of named veterinary surgeon for various small pharmaceutical and biotech companies. She was head of the Veterinary Services Department at the University of Oxford from 1991 until 2010 and then set up a consultancy providing advice on animal health and welfare to clients from the pharmaceutical industry, academia, animal welfare organisations, and funding agencies and governments; both in the UK and overseas. She is involved in the ethical review of projects relating to animal care and use, and was a Veterinary Non-Executive Director of the Veterinary Defence Society. She is an RCVS Recognised Specialist in Laboratory Animal Science, holds the Diploma from the European College of Laboratory Animal Medicine, the Diploma from the European College of Animal Welfare and Behaviour Medicine (Welfare Science, Ethics and Law) and is a Fellow of the Royal Society of Biology. She was awarded an OBE for services to animal welfare in 2012 and Fellowship of the Royal College of Veterinary Surgeons in 2019.
Consumer demand for invertebrates is on the rise as their numbers in the wild dwindle. However, with the growing conservation efforts of modern zoos and aquariums, and evidence from over 300 studies showing that invertebrates are capable of sentience, public interest, and moral concern for welfare of invertebrates have increased. The challenge for zoos and aquariums is in developing an objective and repeatable method for evaluating welfare that can be applied to invertebrates in zoological collections. Recently introduced into zoological collection management is the Animal Welfare Assessment Grid (AWAG). The AWAG helps to identify negative and positive welfare states, through assessing animal- and environmental-based indicators to make changes that lead to a better quality of life. Originally developed for the assessment of laboratory primates, the system has been successfully adapted to assess a variety of taxa across different environments, facilitated by the development of cloud-based software. In this study, the AWAG has been adapted to assess the cumulative lifetime experience of captive decapods and cephalopods at two different institutions, Marwell Zoo and National Marine Aquarium. This study has provided further evidence that the AWAG is adaptable and demonstrates the first time any objective scoring system has been successfully adapted for use in invertebrates. Through graphical representation, the results show that the AWAG identifies changes in welfare scores that can be attributed to specific events and can be used to predict the future vulnerability of species to welfare changes and suggest alternative management methods. This monitoring tool provides a versatile method of implementing practical welfare monitoring in zoos and aquariums.
A primate colony comprising three distinct but interrelated units had long-term history of undiagnosed diarrhea and associated deaths for many years. In 1989, the clinical problem was recognized as a confounding factor for the experimental work, and steps were taken to eradicate the disease. This was done by a combined approach involving improved sample collection techniques and microbiological methods, treatment of all animals in the colony, and improvement in management. These management changes included alterations in basic facility and cage design, disinfection procedures, and continuous routine microbiological sampling of all groups of animals on a random basis, as well as sampling of those suspected to be at risk for stress-associated Shigella shedding. Using this approach, we have eliminated clinical cases of shigellosis and have not have any further isolations of Shigella from this colony.
New to this edition: • Reflects changes in European legislation and their impact on national legislation • Covers recommendations for the education and training of those carrying out animal experiments across Europe • New chapters on ...
Linkage analysis can be problematic in humans because of the lack of large, multigenerational pedigrees and the difficulties in obtaining phenotypic data on all family members. In contrast, large, captive colonies of rhesus macaque are a potentially valuable resource for linkage studies because detailed phenotypic and genealogical data are kept, inbreeding is avoided, and DNA samples can usually be obtained. Microsatellite marker sets for genome-wide screening are available in a number of species, but not for the rhesus macaque. We tested primers to 400 human microsatellite markers from a genome-wide mapping set using DNA from nine unrelated female rhesus macaques. We found that 76 (19%) of the primers amplified a polymorphic product using the standard protocols for human DNA. The average heterozygosity of the markers in humans was 0.80, compared to 0.65 in the rhesus macaques. This study provides preliminary data, which could be used toward the development of a linkage mapping set in this species. There would be a need, however, to confirm the Mendelian inheritance of the markers.
The transportation of primates has become an important welfare issue and the outcome of the debate over its cost to the animal will have effects on the future of medical research using these species. There is a paucity of scientific studies on transport relating to primates and the need for gathering of further scientific evidence is highlighted.
Zoos are required to maintain a high standard of animal welfare, and this can be assessed using a combination of resource-based and animal-based indices usually divided into behavioural indicators, physiological indicators and clinical/pathological signs. Modern animal welfare assessments should aim to encompass positive affective states and the indicators that are useful in assessing these are discussed. When developing factors to be scored for each species, there is huge variability in the available information about the natural biology for some zoo species and even less information concerning those animals in captivity. Wild baselines are not always the most accurate indicator of what is right for an animal in captivity, which makes the identification of factors to include within species-specific welfare assessment even more challenging. When planning a welfare strategy for any species, it is important that the full range of their biological requirements and needs are considered, but this can be challenging for some zoo species and it is not possible to define a “one size fits all” welfare strategy. The different approaches for welfare assessment are reviewed, including the development of the Animal Welfare Assessment Grid which offers an evidence-based tool for continual welfare assessment, using technology where appropriate, to facilitate decision making and lead to improvements in the animals’ quality of life.
More long-tailed macaques (Macaca fascicularis) than any other primate are imported into the UK for research, and journey times may be of up to 58 h. Whilst a number of studies have examined the stress associated with transport, these have typically involved laboratory rodents and livestock, and little is known of its effect on non-human primates. This paper reports the results of a study of behavioural changes in a group of long-tailed macaques transported by air from standard breeding conditions and then re-housed in standard laboratory primate conditions. The animals were studied prior to their departure, immediately after their arrival, and 3 weeks after that. Data were collected on individual time budgets using focal animal sampling and on hierarchy using a feeding trial. The data were analysed for changes in behavioural repertoires and for social perturbation that would be reflected in hierarchical changes. Changes in behaviour occurred which reflected heightened levels of stress in the study group. It was also clear that although there was some adjustment of behaviour, after an initial change on arrival at the new establishment, there was no return to levels observed at the breeding facility within the first month. This study demonstrates that, as a whole, the process of international air transport and re-housing in laboratory conditions may result in the compromising of the welfare of the study animals.
The aim of this study was to conduct a series of paper-based exercises in order to assess the negative (adverse) welfare impacts, if any, of common interventions on domestic horses across a broad range of different contexts of equine care and training. An international panel (with professional expertise in psychology, equitation science, veterinary science, education, welfare, equestrian coaching, advocacy, and community engagement; n = 16) met over a four-day period to define and assess these interventions, using an adaptation of the domain-based assessment model. The interventions were considered within 14 contexts: C1 Weaning; C2 Diet; C3 Housing; C4 Foundation training; C5 Ill-health and veterinary interventions (chiefly medical); C6 Ill-health and veterinary interventions (chiefly surgical); C7 Elective procedures; C8 Care procedures; C9 Restraint for management procedures; C10 Road transport; C11 Activity—competition; C12 Activity—work; C13 Activity—breeding females; and C14 Activity—breeding males. Scores on a 1–10 scale for Domain 5 (the mental domain) gathered during the workshop were compared with overall impact scores on a 1–10 scale assigned by the same panellists individually before the workshop. The most severe (median and interquartile range, IQR) impacts within each context were identified during the workshop as: C1 abrupt, individual weaning (10 IQR 1); C2 feeding 100% low-energy concentrate (8 IQR 2.5); C3 indoor tie stalls with no social contact (9 IQR 1.5); C4 both (i) dropping horse with ropes (9 IQR 0.5) and forced flexion (9 IQR 0.5); C5 long-term curative medical treatments (8 IQR 3); C6 major deep intracavity surgery (8.5 IQR 1); C7 castration without veterinary supervision (10 IQR 1); C8 both (i) tongue ties (8 IQR 2.5) and (ii) restrictive nosebands (8 IQR 2.5); C9 ear twitch (8 IQR 1); C10 both (i) individual transport (7.00 IQR 1.5) and group transport with unfamiliar companions (7 IQR 1.5); C11 both (i) jumps racing (8 IQR 2.5) and Western performance (8 IQR 1.5); C12 carriage and haulage work (6 IQR 1.5); C13 wet nurse during transition between foals (7.5 IQR 3.75); and C14 teaser horse (7 IQR 8). Associations between pre-workshop and workshop scores were high, but some rankings changed after workshop participation, particularly relating to breeding practices. Domain 1 had the weakest association with Domain 5. The current article discusses the use of the domain-based model in equine welfare assessment, and offers a series of assumptions within each context that future users of the same approach may make when assessing animal welfare under the categories reported here. It also discusses some limitations in the framework that was used to apply the model.
Simple Summary: Animal research conducted outside of the laboratory faces various unique challenges, but has received only limited attention in terms of official guidelines, support, and statistics. To improve understanding, we held a workshop bringing together experts familiar with a variety of nonlaboratory animal research contexts (e.g., wildlife field sites, farms, fisheries, veterinary clinics, zoos). We collectively identified five key areas that we propose require further discussion and attention, which we present in this paper. While the workshop focused on research in the UK, our conclusions may have implications for similar work overseas. Abstract: Research involving animals that occurs outside the laboratory raises an array of unique challenges. With regard to UK legislation, however, it receives only limited attention in terms of official guidelines, support, and statistics, which are unsurprisingly orientated towards the laboratory environment in which the majority of animal research takes place. In September 2019, four social scientists from the Animal Research Nexus program gathered together a group of 13 experts to discuss nonlaboratory research under the Animals (Scientific Procedures) Act (A(SP)A) of 1986 (mirroring European Union (EU) Directive 2010/63/EU), which is the primary mechanism for regulating animal research in the UK. Such nonlaboratory research under the A(SP)A often occurs at Places Other than Licensed Establishments (POLEs). The primary objective of the workshop was to assemble a diverse group with experience across a variety of POLEs (e.g., wildlife field sites, farms, fisheries, veterinary clinics, zoos) to explore the practical, ethical, and regulatory challenges of conducting research at POLEs. While consensus was not sought, nor reached on every point of discussion, we collectively identified five key areas that we propose require further discussion and attention. These relate to: (1) support and training; (2) ethical review; (3) cultures of care, particularly in nonregulated research outside of the laboratory; (4) the setting of boundaries; and (5) statistics and transparency. The workshop generated robust discussion and thereby highlighted the value of focusing on the unique challenges posed by POLEs, and the need for further opportunities for exchanging experiences and sharing best practice relating to research projects outside of the laboratory in the UK and elsewhere.
The Animal Welfare Assessment Grid (AWAG) is a method for assessing quality of life, originally designed for experimental primates. This study adapts the AWAG for use in cattle and pigs, by adapting the factors included for these species and including data which had been collected previously as the standard approach to monitoring these species in research. The intention is that the results presented here will allow the future data collected for experimental cattle and pigs to be optimised for inclusion in an AWAG. Data were collected from two vaccine assessment studies at the Pirbright Institute. Factors were scored for every recorded event using retrospective data and CCTV clips. There was a lack of behavioural data recorded in both studies, which limited the accuracy of assessing each animal’s welfare. This paper emphasises the importance of including behavioural information when assessing welfare and not simply relying on assessment of physical condition. Scores peaked following an exponential rise as animals reached set humane end points. This demonstrated the potential of using the AWAG to aid the decision-making of when euthanasia should be performed. Our study shows the AWAG to be a useful tool for assessing welfare, which can be used in harm:benefit assessment.
The recognition of animal suffering is influenced by cultural and societal prejudices and the cuteness of an animal leads to bias in the way it is treated. It is important to consider the animal’s behaviour and its environment—not just its physical condition—when assessing its quality of life. The Animal Welfare Assessment Grid (AWAG) is a useful tool for this purpose. The AWAG offers an evidence-based tool for continual welfare assessment, using technology where appropriate, such as digital activity recording, to facilitate decision-making and lead to improvements in the animals’ quality of life. It is highly adaptable to any species by assessing the four parameters of physical health, psychological wellbeing, environmental quality, and clinical and management procedural events. The outcome of assessing welfare should be action to improve it. Societal ethics and policy-making lead to legislation balancing the values we hold for different species. Influencing policy development in such matters as animal welfare, ecological conservation, and risks to humans requires a focus on public attitudes to, and understanding of, science, as well as consideration of potential unforeseen consequences of the social/environmental/economic impacts of policies.
The objective of this review is to report on whether, and if so, how, scientific research projects organised and managed within collaborative consortia across academia and industry are contributing to the Three Rs (i.e. reduction, replacement and refinement of the use of animals in research). A number of major technological developments have recently opened up possibilities for more direct, human-based approaches leading to a reassessment of the role and use of experimental animals in pharmacological research and biomedicine. This report reviews how projects funded by one of the research funding streams, the Innovative Medicines Initiative (IMI), are contributing to a better understanding of the challenges faced in using animal models. It also looks how the results from these various projects are impacting on the continued use of laboratory animals in research and development. From the progress identified, it is apparent that the approach of private–public partnership has demonstrated the value of multicentre studies, and how the spirit of collaboration and sharing of information can help address human health challenges. In so doing, this approach can reduce the dependence on animal use in areas where it has normally been viewed as necessary. The use of a collaborative platform enables the Three Rs to be addressed on multiple different levels, such that the selection of models to be tested, the protocols to be followed, and the interpretation of results generated, can all be optimised. This will, in turn, lead to an overall reduction in the use of laboratory animals.
Improving laboratory animal science and welfare requires both new scientific research and insights from research in the humanities and social sciences. Whilst scientific research provides evidence to replace, reduce and refine procedures involving laboratory animals (the ‘3Rs’), work in the humanities and social sciences can help understand the social, economic and cultural processes that enhance or impede humane ways of knowing and working with laboratory animals. However, communication across these disciplinary perspectives is currently limited, and they design research programmes, generate results, engage users, and seek to influence policy in different ways. To facilitate dialogue and future research at this interface, we convened an interdisciplinary group of 45 life scientists, social scientists, humanities scholars, non-governmental organisations and policy-makers to generate a collaborative research agenda. This drew on methods employed by other agenda-setting exercises in science policy, using a collaborative and deliberative approach for the identification of research priorities. Participants were recruited from across the community, invited to submit research questions and vote on their priorities. They then met at an interactive workshop in the UK, discussed all 136 questions submitted, and collectively defined the 30 most important issues for the group. The output is a collaborative future agenda for research in the humanities and social sciences on laboratory animal science and welfare. The questions indicate a demand for new research in the humanities and social sciences to inform emerging discussions and priorities on the governance and practice of laboratory animal research, including on issues around: international harmonisation, openness and public engagement, ‘cultures of care’, harm-benefit analysis and the future of the 3Rs. The process outlined below underlines the value of interdisciplinary exchange for improving communication across different research cultures and identifies ways of enhancing the effectiveness of future research at the interface between the humanities, social sciences, science and science policy.
Veterinary professionals working in partnership with other competent persons are essential for a successful animal care and use programme. A veterinarian's primary responsibilities are defined by their own professional regulatory bodies, but in this area of work there are further opportunities for contribution, which will assist in safeguarding the health and welfare of animals used in research. These guidelines are aimed not only at veterinarians to explain their duties, and outline the opportunities to improve the health and welfare of animals under their care, but also at employers and regulators to help them meet their responsibilities. They describe the desirability for postgraduate education towards specialization in laboratory animal medicine and detail the many competencies necessary to fulfil the role of the laboratory animal veterinarian. They detail the need for veterinary expertise to promote good health and good welfare of animals used in biomedical research during husbandry as well as when under experimental procedures. Regulatory and ethical aspects are covered as are the involvement of the veterinarian in education and training of others working in the animal care and use programme. Managerial aspects, including occupational health and safety, are also areas where the veterinarian's input can assist in the successful implementation of the programme.
Animal welfare monitoring is an essential part of zoo management and a legal requirement in many countries. Historically, a variety of welfare audits have been proposed to assist zoo managers. Unfortunately, there are a number of issues with these assessments, including lack of species information, validated tests and the overall complexity of these audits which make them difficult to implement in practice. The animal welfare assessment grid (AWAG) has previously been proposed as an animal welfare monitoring tool for animals used in research programmes. This computer-based system was successfully adapted for use in a zoo setting with two taxonomic groups: primates and birds. This tool is simple to use and provides continuous monitoring based on cumulative lifetime assessment. It is suggested as an alternative, practical method for welfare monitoring in zoos.
This report is based on discussions and submissions from an expert working group consisting of veterinarians, animal care staff and scientists with expert knowledge relevant to the field and aims to facilitate the implementation of the Three Rs (replacement, reduction and refinement) in the use of animal models or procedures involving seizures, convulsions and epilepsy. Each of these conditions will be considered, the specific welfare issues discussed, and practical measures to reduce animal use and suffering suggested. The emphasis is on refinement since this has the greatest potential for immediate implementation, and some general issues for refinement are summarised to help achieve this, with more detail provided on a range of specific refinements.
Combining a range of assessment parameters into one usable entity has been identified as an important goal in providing a practical, objective and robust assessment of welfare, particularly in laboratory animals. This paper refines and extends one such previously published method. The proposed Extended Welfare Assessment Grid provides for the incorporation of changes in the state of an animal over time, allowing for predictive, retrospective, scheduled, or event monitoring. It enables the numeric, as well as visual, representation of the animal's welfare, placing this in the context of the careful and realistic justification for experimental use of the animal. This assessment method represents a valuable tool for those tasked with ensuring ethical oversight, as well as for those planning the use, or monitoring, of animals in research. It is particularly applicable to animals used in long-term studies, especially non-human primates. It is believed that this system will draw attention to the temporal component of suffering that is often overlooked in the planning of research schedules and allow an assessment of cumulative suffering imposed by the events that occur.
From the welfare and ethics of primate captivity through to housing and husbandry systems, environmental enrichment, nutritional requirements, breeding issues, primate diseases, and additional information on transportation and quarantine ...
© 2015 Universities Federation for Animal Welfare.This paper proposes a system that uses intrinsic study data to provide a clear visualisation of the stresses involved during the animal's life history that can be applied to all types of studies, even those not requiring invasive techniques. Thus, it provides an opportunity for researchers to identify and refine key events which impact on the welfare of an animal, and to explain clearly the totality of any necessary harms when justifying the research. Assessment of animal welfare depends on measurement of a number of parameters which will vary according to species, the animal's environment and the scientific procedure, all of which are inter-related. Currently, there are few tools to assess the effects of lifetime events on welfare or even, in some cases, to recognise that they have an impact on the level of suffering. A matrix to assess the combined effects of environment, experimental and contingent events on welfare has been applied, retrospectively, to programmes of work involving macaques (Macaca mulatta and M. fascicularis). Lifetime records, available for animals from their birth in the breeding colony through to experimental use in vaccine efficacy evaluation studies, were analysed as a robust validation test for the assessment matrix and refinement of the way in which information on these events is captured. A meaningful assessment method is required prospectively for project licence applications and retrospectively for licence review or decisions on re-use. The analysis will provide information that would support the application of refinements that would optimally enhance the lives of experimental animals.
The mean (+/- sd) packed cell volume (PCV) of the lambs in a flock mated by 'out-of-season' breeding methods and housed throughout the last six weeks of pregnancy and the whole of the suckling period declined to 23.3 +/- 3.34 per cent when the lambs were a month old, but recovered spontaneously to reach values within the normal range (30 to 35 per cent) before they were weaned at two months. Clinical signs of anaemia were observed in only a few lambs at three weeks old but the PCV values of all the lambs were significantly lower at this time than at weaning. There was no relationship between the PCV values during the two to four weeks after birth and the growth rate of the lambs. The administration of 200 mg iron, as iron dextran, by intramuscular injection to the newborn lambs prevented the decrease in PCV, but had no measurable effect on the health or growth rate of the lambs throughout the suckling period.
A Working Party of the UK group of European Primate Resources Network (EUPREN) considered primate supply for scientific work in the UK. Through a questionnaire, which achieved a very good response, it obtained details of primate use, sources and breeding in the UK and it put forward options to ensure that animal welfare is the best possible whilst ensuring continued supply. The questionnaire showed that contract research laboratories and pharmaceutical companies use about 80% of the 4233 primates used annually at the moment, with the rest accounted for by academic establishments and public sector laboratories. Fifty-four per cent are cynomolgus macaques (Macaca fascicularis), of which nearly 90% are captive-bred outside the European Union (EU), the remainder being bred in the UK. Nearly 90% of cynomolgus macaques are used by only five institutions. Thirty-seven per cent of primates used are marmosets (Callithrix jacchus jacchus), all of which are bred in the UK. Most of the rest are rhesus macaques (Macaca mulatta), about half of which are captive-bred outside the EU, the other half being bred in the UK. Overall primate use has increased from about 3000 per year in 1990 and users predict that requirements for all species except baboons (Papio sp.) will be maintained or increase. Marmoset breeding in the UK is already closely matched to use, and it could be increased reasonably easily if necessary. Some of the existing breeding centres of macaques in the UK would be prepared to consider expanding to supply others, although investment and imported breeding stock would be needed and it is likely that a large investment would be needed to breed a significant fraction of the macaque use in the UK. A further problem is that the users of only about 10% of the cynomolgus macaques said that they could replace this species by rhesus macaques, which are easier to breed in the UK. The questionnaire showed that much of the use of macaques would be transferred to other countries equally remote from the natural source countries of the animals, if constraints on primate use became more severe in the UK. Users felt that it is unlikely that much of the work could be transferred to the natural source countries themselves. A review of the literature revealed a paucity of information on the effects of transport on primate welfare. The importance of obtaining this information before making decisions about alternative means of supply is stressed. Current schemes for the accreditation of primate breeders were reviewed. A list of options is presented for discussion. Users vary so much in their requirements that it is unlikely that one means of supply will be applicable to all. Animal welfare will benefit and supply will be more certain if cooperation between those concerned (preferably through the UK group of EUPREN) is maintained.
Refinement of scientific procedures carried out on protected animals is an iterative process, which begins with a critical evaluation of practice. The process continues with objective assessment of the impact of the procedures, identification of areas for improvement, selection and implementation of an improvement strategy and evaluation of the results to determine whether there has been the desired effect, completing the refinement loop and resulting in the perpetuation of good practice. Refinements may be science-driven (those which facilitate getting high-quality results) or welfare-driven or may encompass both groups, but whatever the driver, refinements almost always result in benefits to both welfare and science. Refinements can be implemented in all aspects of animal use: improved methodology in invasive techniques, housing and husbandry, and even statistical analyses can all benefit animal welfare and scientific quality. If refinement is not actively sought, outdated and unnecessarily invasive techniques may not be replaced by better methods as they become available, and thus outdated information is passed down to the next generation, causing perpetuation of old-fashioned methods. This leads to a spiral of ignorance, leading ultimately to poor practice, poor animal welfare and poor-quality scientific data. Refinement is a legal and ethical requirement, yet refinements may not always be implemented. There are numerous obstacles to the implementation of refinement, which may be real or perceived. Either way, in order to take refinement forward, it is important to coordinate the approach to refinement, validate the science behind refinement, ensure there is adequate education and training in new techniques, improve liaison between users and make sure there is feedback on suitability of refinements for use. Overall, refinement requires a coordinated ongoing process of critical appraisal of practice and active scrutiny of resources for likely improvements. In the busy world of biomedical research, this process needs help. In order to develop these themes further, a workshop was held at the LASA Winter Meeting 2006, UK, to assist in identifying potential obstacles to refinement, and then to explore and develop strategies for overcoming these obstacles in key areas. A range of strategies appropriate to different circumstances was identified, which should facilitate the implementation of refinements.
Male animals of many species use conspicuous coloration to attract mates. Among mammals, primates possess the most brilliant secondary sexual coloration. However, whether colour plays a part in primate female mate choice remains unknown. Adult male rhesus macaques undergo a hormonally regulated increased reddening of facial and anogenital skin during their mating season. We experimentally investigated whether red male facial coloration is preferred by simultaneously presenting female rhesus macaques (n = 6) with computer-manipulated pale and red versions of 24 different male faces. The duration and direction of gaze were measured to discern visual preferences. Females exhibited preferences for the red versions of male faces. It is proposed that male coloration might provide a cue to male quality.
A technique measuring leukocyte (neutrophil) activity was used to examine differences between stress levels in a breeding colony of rhesus macaques housed in either a traditional caging system or open-rooms. The leukocyte activation test measured the degree to which blood from the two treatment groups could launch a further neutrophil response (superoxide production) to an in vitro challenge. Animals housed in a traditional caging system produced a significantly lower leukocyte response than animals housed in open-rooms, indicating that there was a higher level of stress associated with caged housing than open-room housing. This was not influenced by whether animals were physically restrained or trained to stand for a sedating injection. No differences were found between treatment groups in leukocyte numbers or composition. This study validates the use of the leukocyte activation test to assess physiological stress levels in non-human primates and demonstrates the animal welfare benefits of open-room housing over traditional laboratory caging systems. © 2005 Universities Federation for Animal Welfare.
Deficiencies of dietary calcium and/or vitamin D will cause hypocalcaemia, leading to metabolic bone disease. The disease commonly affects young rapidly growing animals and this is a report of the condition in a colony of rhesus macaques (Macaca mulatta). A clinical problem of metabolic bone disease was seen in 1993, when it was treated and resolved satisfactorily. However it recurred in 1999 following changes in management and husbandry of the colony, at which time the clinical manifestations were more serious. The animals had bowed tibia, fibula, radius and ulna and enlarged epiphyses, were reluctant to climb and jump, had a 'hopping' gait and poor growth. The syndrome had a multifactorial aetiology involving a combination of staff and management changes, a borderline nutritional deficit, a lack of daylight for production of vitamin D, and a possible familial predisposition.