Opportunities for refinement in neuroscience: Indicators of wellness and post-operative pain in laboratory macaques.

Being able to assess pain in nonhuman primates undergoing biomedical procedures is important for preventing and alleviating pain, and for developing better guidelines to minimise the impacts of research on welfare in line with the 3Rs principle of Refinement. Nonhuman primates are routinely used biomedical models however it remains challenging to recognise negative states, including pain, in these animals. This study aimed to identify behavioural and facial changes that could be used as pain or general wellness indicators in the rhesus macaque (Macaca mulatta). Thirty-six macaques scheduled for planned neuroscience procedures were opportunistically monitored at four times: Pre-Operative (PreOp), Post-Operative (PostOp) once the effects of anaesthesia had dissipated, Pre-Analgesia (PreAn) on the subsequent morning prior to repeating routine analgesic treatment, and Post-Analgesia (PostAn) following administration of analgesia. Pain states were expected to be absent in PreOp, moderate in PreAn, and mild or absent in PostOp and PostAn when analgesia had been administered. Three potential pain indicators were identified: lip tightening and chewing, which were most likely to occur in PreAn, and running which was least likely in PreAn. Arboreal behaviour indicated general wellness, while half-closed eyes, leaning of the head or body shaking indicated the opposite. Despite considerable individual variation, behaviour and facial expressions could offer important indicators of pain and wellness and should be routinely quantified, and appropriate interventions applied to prevent or alleviate pain, and promote positive welfare.

A protocol for training group-housed rhesus macaques (Macaca mulatta) to cooperate with husbandry and research procedures using positive reinforcement.

There has been increased recognition of the 3Rs in laboratory animal management over the last decade, including improvements in animal handling and housing. For example, positive reinforcement is now more widely used to encourage primates to cooperate with husbandry procedures, and improved enclosure design allows housing in social groups with opportunity to escape and avoid other primates and humans. Both practices have become gold standards in captive primate care resulting in improved health and behavioural outcomes. However, training individuals and social housing may be perceived as incompatible, and so it is important to share protocols, their outcomes and suggestions for planning and improvements for future uptake. Here we present a protocol with link to video for training rhesus macaques (Macaca mulatta) housed in single-male - multi-female breeding groups to sit at individual stations in the social enclosure. Our aim was that the monkeys could take part in welfare-related cognitive assessments without the need for removal from the group or interference by group members. To do this we required most individuals in a group to sit by individual stations at the same time. Most of the training was conducted by a single trainer with occasional assistance from a second trainer depending on availability. We successfully trained 61/65 monkeys housed in groups of up to nine adults (plus infants and juveniles) to sit by their individual stationing tools for >30 s. Males successfully trained on average within 30 min (2 training sessions); females trained on average in 1 h 52 min ± 13min (7.44 sessions), with rank (high, mid, low) affecting the number of sessions required. On average, dominant females trained in 1 h 26 min ± 16 min (5.7 sessions), mid ranked females in 1 h 52 min ± 20min (7.45 sessions), and subordinate females took 2 h 44 min ± 36 min (10.9 sessions). Age, group size, reproductive status, temperament, and early maternal separation did not influence the number of sessions a monkey required to reach criterion. We hope this protocol will be useful for facilities worldwide looking to house their animals in naturalistic social groups without impacting on animal husbandry and management.

An automated system for positive reinforcement training of group-housed macaque monkeys at breeding and research facilities.

BACKGROUND: Behavioural training through positive reinforcement techniques is a well-recognised refinement to laboratory animal welfare. Behavioural neuroscience research requires subjects to be trained to perform repetitions of specific behaviours for food/fluid reward. Some animals fail to perform at a sufficient level, limiting the amount of data that can be collected and increasing the number of animals required for each study. NEW METHOD: We have implemented automated positive reinforcement training systems (comprising a button press task with variable levels of difficulty using LED cues and a fluid reward) at the breeding facility and research facility, to compare performance across these different settings, to pre-screen animals for selection and refine training protocols. RESULTS: Animals learned 1- and 4-choice button tasks within weeks of home enclosure training, with some inter-individual differences. High performance levels (∼200-300 trials per 60min session at ∼80% correct) were obtained without food or fluid restriction. Moreover, training quickly transferred to a laboratory version of the task. Animals that acquired the task at the breeding facility subsequently performed better both in early home enclosure sessions upon arrival at the research facility, and also in laboratory sessions. COMPARISON WITH EXISTING METHOD(S): Automated systems at the breeding facility may be used to pre-screen animals for suitability for behavioural neuroscience research. In combination with conventional training, both the breeding and research facility systems facilitate acquisition and transference of learning. CONCLUSIONS: Automated systems have the potential to refine training protocols and minimise requirements for food/fluid control.

Facial expression: An under-utilised tool for the assessment of welfare in mammals.

Animal welfare is a key issue for industries that use or impact upon animals. The accurate identification of welfare states is particularly relevant to the field of bioscience, where the 3Rs framework encourages refinement of experimental procedures involving animal models. The assessment and improvement of welfare states in animals depends on reliable and valid measurement tools. Behavioral measures (activity, attention, posture and vocalization) are frequently used because they are immediate and non-invasive, however no single indicator can yield a complete picture of the internal state of an animal. Facial expressions are extensively studied in humans as a measure of psychological and emotional experiences but are infrequently used in animal studies, with the exception of emerging research on pain behavior. In this review, we discuss current evidence for facial representations of underlying affective states, and how communicative or functional expressions can be useful within welfare assessments. Validated tools for measuring facial movement are outlined, and the potential of expressions as honest signals is discussed, alongside other challenges and limitations to facial expression measurement within the context of animal welfare. We conclude that facial expression determination in animals is a useful but underutilized measure that complements existing tools in the assessment of welfare.