Research primates may undergo surgical procedures making effective pain management essential to ensure good animal welfare and unbiased scientific data. Adequate pain mitigation is dependent on whether veterinarians, technicians, researchers, and caregivers can recognize and assess pain, as well as the availability of efficacious therapeutics. A survey was conducted to evaluate primate veterinary approaches to pain assessment and alleviation, as well as expressed challenges for adequately managing primate pain. The survey (n = 93 respondents) collected information regarding institutional policies and procedures for pain recognition, methods used for pain relief, and perceived levels of confidence in primate pain assessment. Results indicated that 71% (n = 60) of respondents worked at institutions that were without formal experimental pain assessment policies. Pain assessment methods were consistent across respondents with the majority evaluating pain based on changes in general activity levels (100%, n = 86) and food consumption (97%, n = 84). Self-reported confidence in recognizing and managing pain ranged from slightly confident to highly confident, and there was a commonly expressed concern about the lack of objective pain assessment tools and science-based evidence regarding therapeutic recommendations of analgesics for research primates. These opinions correspond with significant gaps in the primate pain management literature, including limited specific pharmacokinetic data and efficacy testing for commonly used analgesics in research primate species as well as limited research on objective and specific measures of pain in research primates. These results demonstrate that there are inconsistencies in institutional policies and procedures surrounding pain management in research primates and a lack of objective pain assessment methods. Demonstrating the gaps and challenges in primate pain management can inform guideline development and suggest areas for future research.

Cynomolgus macaques may undergo surgical procedures for scientific and veterinary purposes. Recognition and assessment of pain using validated tools is a necessary first step for adequately managing pain in these primates. Grimace scales are one means of assessing the occurance of acute pain using action units such as facial expressions and posture. The aim of this study was to create and validate a Cynomolgus Macaque Grimace Scale (CMGS). Cynomolgus macaques (n = 43) were video recorded before and after a surgical procedure. Images were extracted from videos at timepoints at which breakthrough pain might be expected based on analgesic pharmacokinetics. Using the CMGS images were scored by 12 observers blinded to animal identification, times, and conditions. To validate the tool, detailed behavioral analyses emphasizing changes to baseline activity ethograms were compared to grimace scores. Four action units were identified related to potential pain including orbital tightening, brow lowering, cheek tightening, and hunched posture. The CMGS tool was found to have moderate inter- (ICCaverage action unit mean ± SD: 0.67 ± 0.28) and good intra- (ICCsingle mean ± SD: 0.79 ± 0.14) observer reliability. Grimace scores increased significantly (p < 0.0001) in the first four post-operative timepoints compared to baseline, correlating with behavioral findings (rho range = 0.22–0.35, p < 0.001). An analgesic intervention threshold was determined and should be considered when providing additional pain relief. The CMGS was shown to be a reliable and valid tool; however, more research is needed to confirm external validity. This tool will be highly valuable for refining analgesic protocols and acute peri-procedural care for cynomolgus macaques.

Little research has been conducted to examine the influence of various methods of providing nest materials—such as dispersing them, providing them as single units, or clustering them—on the behavior and welfare of group-housed mice. In this study, 6 wk-old C57BL/6NCrl mice were housed 3 per cage and randomized into 1 of 3 nest-material groups: 1) one facial tissue per cage (control; female mice, 3 cages; male mice, 3 cages); 2) an 8-g ‘puck’ of compressed nesting material and a facial tissue (females, 3 cages; males, 3 cages); or 3) 8 g of dispersed paper strips and a facial tissue (females, 3 cages; males, 3 cages). Mouse behavior (agonistic, stereotypic, nesting), physical examination data, and nest scores were evaluated over 16 d. The results showed that mice in the puck and control groups spent more time manipulating nest materials after cage changes than did mice in the paper-strip group. Average nest scores were highest in the paper-strip group compared with controls and puck cages. Female cages with pucks showed no barbering, whereas all other female mice cages demonstrated barbering. Overall, nest pucks may provide a time-consuming activity for mice and may help protect female C57BL/6 mice from barbering. However, more research is needed to replicate and expand these study results.