Postoperative pain behaviours in rabbits following orthopaedic surgery and effect of observer presence

Turkish Cross-cultural Adaptation of the Post Hospitalization Behavior Questionnaire for Ambulatory Surgery (PHBQ-AS)

PURPOSE

The purpose of this study is to cross-culturally adapt the Post Hospitalization Behavior Questionnaire for Ambulatory Surgery (PHBQ-AS) to Turkish and test its validity and reliability.

DESIGN

This is a methodological study.

METHODS

This study was conducted with 121 children aged 1 to 12 years who underwent ambulatory surgery. The data of the study were collected using a Descriptive Information Form, PHBQ-AS, and the Parents' Postoperative Pain Measure. Data analysis and evaluation were performed using factor analysis, Cronbach's α analysis, item-total score correlation analysis, content validity, construct validity, and concurrent validity.

FINDINGS

PHBQ-AS showed a high level of internal consistency (Cronbach's α = 0.801). The item-total correlation values of PHBQ-AS were found to be 0.458 to 0.753. PHBQ-AS was determined to be a single-factor scale explaining 66% of the variance in the examined variable. PHBQ-AS and Parents' Postoperative Pain Measure scores were moderately correlated.

CONCLUSIONS

The Turkish version of PHBQ-AS was highly valid and reliable for the Turkish population. A recommendation for health care professionals in Turkey is to use the PHBQ-AS scale to evaluate posthospitalization behavioral changes in children who are admitted for ambulatory surgery.

Extended Release of Bupivacaine from Temperature-Responsive PNDJ Hydrogels Improves Postoperative Weight-Bearing in Rabbits Following Knee Surgery

Effective treatment of postoperative pain lasting for multiple days without opioids is an important clinical need. We previously reported analgesia lasting up to 96 h in a porcine soft tissue model of postoperative pain using SBG004, an extended-release formulation of bupivacaine based on the temperature-responsive polymer poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylamide-co-Jeffamine M-1000 acrylamide) [PNDJ]. Orthopaedic surgical sites such as the knee can involve complex sensory innervation which presents a distinct challenge to local anesthetic delivery. The purpose of this work was to evaluate the pharmacokinetics and efficacy of SBG004 in an orthopaedic surgical model in comparison to currently available local anesthetics. Pharmacokinetics following periarticular (PA) or intraarticular (IA) injection of SBG004 were compared against liposomal bupivacaine (Lip-Bupi) PA in New Zealand White rabbits (all doses 14.5 mg/kg). Analgesic efficacy of SBG004 (IA, PA, or IA + PA), three active comparators, and saline was evaluated following knee surgery in New Zealand White rabbits. Analgesia was assessed via weight-bearing on the operated limb during spontaneous large steps in video recordings. Systemic bupivacaine exposure lasted at least 7 days for SBG004 PA, 4 days for SBG004 IA, and 2 days for Lip-Bupi PA. In the analgesia study, weight-bearing in all active groups except SBG004 IA was more frequent versus saline through 8 h postoperatively (p < 0.05). Only SBG004 IA + PA resulted in a higher proportion of weight-bearing rabbits at 24 h versus saline (6/7 versus 2/10, p = 0.015). Analysis of pooled data from 24-72 h showed significantly greater frequency of weight-bearing in rabbits receiving SBG004 IA + PA (71%) versus saline (37%), ropivacaine cocktail (41%), and Lip-Bupi PA (36%). The results indicate that the release profile from SBG004 PA or IA coincides reasonably with the time course of postoperative pain, and SBG004 may produce longer duration of analgesia than local anesthetics currently used in knee surgery, including during the period of 24-72 h recognized as a target for extended-release local anesthetics.

Pharmacokinetics, Fecal Output, and Grimace Scores in Rabbits Given Long-acting Buprenorphine or Fentanyl for Postsurgical Analgesia

The New Zealand white rabbit (Oryctolagus cuniculus) is a frequently used surgical model. Pain management after surgery is a critical aspect of animal welfare. Recently, a long-acting buprenorphine formulation (Ethiqa XR; EXR) was approved for use in rats and mice but has not yet been investigated in rabbits. The current study aimed to determine whether a single subcutaneous dose of 0.15mg/kg of EXR could achieve and maintain therapeutic buprenorphine plasma concentrations (0.1ng/mL) for 72h in male and female rabbits. We also evaluated the safety profiles of EXR and the fentanyl patch (FP) by assessing fecal output after surgery, because opioids are known to decrease intestinal motility. Behavior and pain scores were compared for rabbits that received either EXR or the FP after undergoing an annulus puncture procedure to induce osteoarthritis. EXR at 0.15mg/kg SC provided a shorter time to onset and sustained analgesia for 72h in male and female rabbits, whereas the FP provided suboptimal analgesia after 48h. Both EXR and FP reduced fecal output after surgery. Output returned to baseline levels within 72h for the EXR group and remained slightly below baseline at 96h after surgery for the fentanyl group. Grimace pain scores revealed no significant difference between treatment groups. These results suggest that EXR is a safe and effective option for postoperative pain management in rabbits.

The Elephant in the Room: Recognition and Documentation of Personnel Practices That Confound Reproducibility

The ability to apply findings from animal studies efficiently and effectively is predicated on an understanding of biology and pathobiology, how that biology relates to the human systems being modeled, and how the studies are conducted and reported. This overview discusses various factors in research within the animal environment (referred to as extrinsic factors) that the NIH now expects to be documented to foster replicability in science and expand interpretations of study outcomes. Specifically, an important extrinsic factor in research with animals is that of individual personnel who perform handling practices, participate in research interactions, and share an overall presence in the housing facility with animals, all of which can confound reproducibility efforts in biomedical science. An improved understanding of the influences and behaviors of animal research personnel on animal responses is critical with regard to research results and the interpretation of data collected from animal models of biomedical disease.

Refinement and revalidation of the Equine Ophthalmic Pain Scale: R-EOPS a new scale for ocular pain assessment in horses

This study addresses the refinement and revalidation of a composite pain scale that focuses on equine facial expressions and behavioural indicators as exhibitions of ophthalmic pain. This scale included only Behavioural and Facial and Ocular expression indicators and, compared to the first version of Equine Ophthalmic Pain Scale (EOPS), item descriptors and related ratings were changed. Thirteen horses with ocular diseases that required medical or surgical treatment were enroled (group P). In each animal, the refined EOPS (R-EOPS) was applied prior to any treatment (T0) and one week later (T7). The R-EOPS was applied twice, 7 days apart, to 16 healthy control horses (group C). Two 30-second videos were recorded each time to allow the retrospective analysis by eight observers. Inter-observer reliability of items was moderate or substantial (Krippendorff's alpha, Kα>0.40) while their intra-observer reliability was substantial or almost perfect for most items (Kα ≥0.61). Both inter- and intra-observer reliability of Total Score (TS) were however excellent (Intraclass Correlation Coefficients, ICC>0.75). The TS also showed good reproducibility (Kendall coefficient=0.786, ICC=0.684) and high consistency of its items (Cronbach's α=0.847). The comparison between groups as well as the sensitivity and specificity values supported the validity of the R-EOPS. In particular, for each extra point added to the TS, the risk of the horse having pain increased by more than two times (Odds Ratio=2.079, 95%CI=1.542-2.804; P<0.001). The Receiver Operating Characteristic analysis identified 6 as the threshold value of R-EOPS for discriminating horses with ocular pathology (sensitivity=83%, specificity=100%). This scale may be an effective tool for reliably assessing the pain level in horses with ophthalmic diseases and potentially guiding pain management although it still requires large-scale application and external validation.

Establishing New Isosexual Pairs in Adult Male Guinea Pigs (Cavia porcellus) to Facilitate Social Housing

Guinea pigs (Cavia porcellus) are a commonly used species in biomedical research. As social creatures, compatible guinea pigs should be housed together unless scientific objectives or veterinary care require otherwise. Extensive literature suggests that adult male guinea pigs are highly aggressive in the presence of females, but data are lacking regarding the compatibility of cohoused adult males in the absence of females. Most studies that use adult males do not report housing densities. We used serial wound scoring and observations of behavior to determine whether unfamiliar adult male guinea pigs will develop stable, prosocial isosexual pairs. Wound scoring was performed before and 24 h after pairing. Serial behavioral observations assessed affiliative and agonistic behaviors at 0.5, 2, 24, and 48 h after pairing. Wound scoring and behavioral observations continued weekly for 1 mo and monthly thereafter. Wound scores were significantly higher at 24 h after pairing as compared with baseline and all other time points. Wounding was rare after week 2, indicating reduced aggression. Furthermore, affiliative behaviors significantly increased over time while agonistic behaviors were rare. Together, these data suggest that unfamiliar adult male guinea pigs establish stable prosocial pairs after an acclimation period. As was done in the present study, providing ample space, separate shelters for each animal, and the absence of female guinea pigs will likely facilitate successful pairing. We recommend consideration of a social housing program for adult male guinea pigs to provide companionship and enrich their housing environment.

Effects of assessment method (real-time versus video-recorded) on a validated pain-altered behavior scale used in castrated piglets

We aimed to compare two assessment methodologies (real-time vs. video-recorded) using the Unesp-Botucatu Pig Composite Acute Pain Scale (UPAPS) in piglets before and after castration. Twenty-nine male piglets were castrated. Four observers scored the UPAPS over three perioperative timepoints of castration following two assessment methodologies. In real-time assessments, the observers were in-person observing the piglets in front of the pen. After two weeks, the observers did video-recorded assessments randomizing piglets and timepoints. Modeling was conducted to compare the UPAPS and each pain-altered behavior between methodologies. Intraclass correlation coefficient (ICC), Bland-Altman, and Lin's concordance correlation coefficient (CCC) were conducted to investigate agreement between methodologies. UPAPS was statistically equivalent between methodologies (P = 0.4371). The ICC for each method was very good (0.85 to 0.91). The agreement of the UPAPS assessed between methodologies had minimal bias (- 0.04), no proportion bias, and 53% of the assessments presented a perfect agreement. However, CCC of the UPAPS was moderate (0.65), and only one pain-altered behavior ("presents difficulty in overcoming obstacles or other animals") occurred more in real-time assessments (P = 0.0444). In conclusion, piglet pain assessment by UPAPS can be conducted in real-time based on a suitable agreement between the real-time and video-recorded assessment methods.

Development and Validation of the Unesp-Botucatu Goat Acute Pain Scale

We aimed to develop and validate the Unesp-Botucatu goat acute pain scale (UGAPS). Thirty goats (5 negative controls and 25 submitted to orchiectomy) were filmed for 7 min at the time points 24 h before and 2 h, 3 h (1 h after analgesia), and 24 h after orchiectomy. After content validation, according to an ethogram and literature, four blind observers analyzed the videos randomly to score the UGAPS, repeating the same assessment in 30 days. According to the confirmatory factor analysis, the UGAPS is unidimensional. Intra- and interobserver reliability was very good for all raters (Intraclass correlation coefficient ≥85%). Spearman's correlation between UGAPS versus VAS was 0.85 confirming the criterion validity. Internal consistency was 0.60 for Cronbach's α Cronbach and 0.67 for McDonald's ω. The item-total correlation was acceptable for 80% of the items (0.3-0.7). Specificity and sensitivity based on the cut-off point were 99% and 90%, respectively. The scale was responsive and demonstrated construct validity shown by the increase and decrease of scores after surgery pain and analgesia, respectively. The cut-off point for rescue analgesia is ≥3 of 10, with an area under the curve of 95.27%. The UGAPS presents content, criterion, and construct validities, responsiveness, and reliability to assess postoperative pain in castrated goats.

Efficacy of inguinal buffered lidocaine and intranasal flunixin meglumine on mitigating physiological and behavioral responses to pain in castrated piglets

Managing castration pain on US sow farms is hindered by the lack of Food and Drug Administration (FDA) approved products for mitigating pain. Previous work assessing flunixin meglumine (FM) efficacy in mitigating castration pain has shown the drug to be effective in pigs, meanwhile, results from previous work evaluating lidocaine efficacy are contradictory. Therefore, the objectives of this study were to determine the efficacy of inguinal buffered lidocaine (BL) and FM in mitigating castration pain in piglets. This study was divided into Part I (physiological response) and Part II (behavioral response). For part I piglets were randomly assigned to the following treatments: T1: (C) Castration plus physiological saline; T2: (S) Sham plus physiological saline; T3: (CL) Castration plus BL; T4: (SL) Sham plus BL; T5: (CF) Castration plus FM; T6: (SF) Sham plus FM; T7: (CLF) Castration plus BL and FM; T8: (SLF) Sham plus BL and FM. Blood was collected 24 h prior to castration, 1 h, and 24 h post castration for cortisol quantification. For Part II another cohort of piglets was enrolled and randomly assign to the following treatments: T1: (C) Castration plus physiological saline and T7: (CLF) Castration plus BL and FM. Behavior scoring was obtained in real-time by observing each piglet for 4-min continuously using Unesp-Botucatu pig acute pain scale (UPAPS) at the following timepoints: 1 h before castration (-1 h), immediately post-castration (0 h), and 3 h post-castration (+3 h). Average cortisol concentrations did not differ at -24 h (P > 0.05) or at 24 h post-castration (P > 0.05) between treatments. At 1 h post-castration, castrated piglets (C and CL) demonstrated greater cortisol concentrations (P < 0.05). Castrated piglets in the CF and CLF group had lower cortisol concentrations compared to C and CL-treated pigs (P < 0.05). For behavioral response, there were no differences between treatments on total UPAPS scores (C and CLF, P > 0.05). Intranasal FM was able to effectively reduce the physiological piglet's response immediately post-castration. Inguinal buffered lidocaine had no effect on the either physiological or behavioral response to pain. Long-term research should focus on refining injection techniques for inguinal BL and consider administration frequency and dosing of intranasal FM to control pain for a longer period post-castration.

Validation of the Unesp-Botucatu pig composite acute pain scale (UPAPS) in piglets undergoing castration

To accurately assess pain and support broadly-based analgesic protocols to mitigate swine pain, it is imperative to develop and validate a species-specific pain scale. The objective of this study was to investigate the clinical validity and reliability of an acute pain scale (UPAPS) adapted for newborn piglets undergoing castration. Thirty-nine male piglets (five days of age, 1.62 ± 0.23 kg BW) served as their own control, were enrolled in the study and underwent castration in conjunction with an injectable analgesic administered one-hour post-castration (flunixin meglumine 2.2 mg/kg IM). An additional 10, non-painful female piglets were included to account for the effect of natural behavioral variation by day on pain scale results. Behavior of each piglet was video recorded continuously at four recording periods (24 h pre-castration, 15 min post-castration, 3 and 24 h post-castration). Pre- and post-operative pain was assessed by using a 4-point scale (score 0-3) including the following six behavioral items: posture, interaction and interest in surroundings, activity, attention to the affected area, nursing, and miscellaneous behavior. Behavior was assessed by two trained blinded observers and statistical analysis was performed using R software. Inter-observer agreement was very good (ICC = 0.81). The scale was unidimensional based on the principal component analysis, all items except for nursing were representative (rs ≥ 0.74) and had excellent internal consistency (Cronbach's alpha ≥ 0.85). The sum of scores were higher in castrated piglets post-procedure compared to pre-procedure, and higher than in non-painful female piglets confirming responsiveness and construct validity, respectively. Scale sensitivity was good when piglets were awake (92.9%) and specificity was moderate (78.6%). The scale had excellent discriminatory ability (area under the curve > 0.92) and the optimal cut-off sum for analgesia was 4 out of 15. The UPAPS scale is a valid and reliable clinical tool to assess acute pain in castrated pre-weaned piglets.

Pain Recognition and Assessment in Birds

The recognition and assessment of pain in avian species are crucial tools in providing adequate supportive care in clinical, laboratory, zoologic, rehabilitation, and companion animal settings. With birds being a highly diverse class of species, there is still much to be determined regarding how to create specific criteria to recognize and assess pain in these animals. This article provides a clinical review on the physiology of pain in birds, observed behavioral and physiologic alterations with pain, how different sources and degrees of pain can alter behaviors observed, and how this information can be applied in a clinical setting.

Pain Recognition in Rabbits

Rabbits typically undergo at least one painful procedure during their lifetime and appropriate methods of assessment are essential to reduce or alleviate pain. Various methods of assessing pain in rabbits have been investigated, with the validity of spontaneous behavior and grimace scale scoring being the most studied to date. Assessment of pain is challenging, compounded by rabbits being a prey species that display freezing behavior in the presence of unfamiliar caregivers. Here we discuss some key changes in rabbits that can be used in the assessment of pain and provide some practical suggestions to ensure that the assessment can be carried out effectively.

Enhanced nociceptive behavior and expansion of associated primary afferents in a rabbit model of cerebral palsy

Spastic cerebral palsy (CP) is a movement disorder marked by hypertonia and hyperreflexia; the most prevalent comorbidity is pain. Since spinal nociceptive afferents contribute to both the sensation of painful stimuli as well as reflex circuits involved in movement, we investigated the relationship between prenatal hypoxia-ischemia (HI) injury which can cause CP, and possible changes in spinal nociceptive circuitry. To do this, we examined nociceptive afferents and mechanical and thermal sensitivity of New Zealand White rabbit kits after prenatal HI or a sham surgical procedure. As described previously, a range of motor deficits similar to spastic CP was observed in kits born naturally after HI (40 min at ~70%-80% gestation). We found that HI caused an expansion of peptidergic afferents (marked by expression of calcitonin gene-related peptide) in both the superficial and deep dorsal horn at postnatal day (P)5. Non-peptidergic nociceptive afferent arborization (labeled by isolectin B4) was unaltered in HI kits, but overlap of the two populations (peptidergic and non-peptidergic nociceptors) was increased by HI. Density of glial fibrillary acidic protein was unchanged within spinal cord white matter regions important in nociceptive transmission at P5. We found that mechanical and thermal nociception was enhanced in HI kits even in the absence of motor deficits. These findings suggest that prenatal HI injury impacts spinal sensory pathways in addition to the more well-established disruptions to descending motor circuits. In conclusion, changes to spinal nociceptive circuitry could disrupt spinal reflexes and contribute to pain experienced by individuals with CP.

Validation of the rabbit pain behaviour scale (RPBS) to assess acute postoperative pain in rabbits (Oryctolagus cuniculus)

Considering the widespread use of rabbits in research that potentially causes pain and discomfort and the limited number of pain assessment validated tools in this species, we aimed to develop and validate a scale of acute postoperative pain in rabbits (RPBS). Footage of 58 rabbits from previous studies were used, recorded at 'baseline' (before orthopaedic and soft tissue surgeries), 'pain' (after surgery), 'analgesia' (after analgesic), and '24h post' (24 hours after surgery). The videos were randomised and assessed twice by four evaluators, within one-month interval between evaluations. After content validation, RBPS was further refined using the criteria from the validation. According to the principal component analysis, RPBS was considered unidimensional. The intra- and inter-observer reliability was excellent (ICC>0.80) for all evaluators. There was a high Spearman's correlation of the RPBS with unidimensional scales (>0.80) and a moderate correlation with the Rabbit Grimace Scale (0.68), confirming criterion validity. According to the mixed linear model, the scale was responsive, shown by the increase in pain scores after surgery. Construct validity was confirmed by known-group approach and internal relationships among items. Adequate item-total correlation (>0.3) was observed for all items, except for the attention to the affected area (0.04). The internal consistency was very good (Cronbach's α coefficient = 0.78; Mcdonald's ω coefficient = 0.83). The cut-off score for rescue analgesia was ≥3, with an area under the curve >0.95, demonstrating a high discriminatory capacity of the instrument. Scores 3 and 4 were within the uncertainty diagnostic zone. Specificity was 87% and sensitivity was 90%. It was concluded that the RPBS presented content, criterion, and construct validities, responsiveness, and reliability to assess acute pain in rabbits submitted to orthopaedic and soft tissue surgeries. The cut-off for rescue analgesia serves as a basis for the administration of analgesics to rabbits submitted to painful procedures.

Multilingual validation of the short form of the Unesp-Botucatu Feline Pain Scale (UFEPS-SF)

Background

Pain is the leading cause of animal suffering, hence the importance of validated tools to ensure its appropriate evaluation and treatment. We aimed to test the psychometric properties of the short form of the Unesp-Botucatu Feline Pain Scale (UFEPS-SF) in eight languages.

Methods

The original scale was condensed from ten to four items. The content validation was performed by five specialists in veterinary anesthesia and analgesia. The English version of the scale was translated and back-translated into Chinese, French, German, Italian, Japanese, Portuguese and Spanish by fluent English and native speaker translators. Videos of the perioperative period of 30 cats submitted to ovariohysterectomy (preoperative, after surgery, after rescue analgesia and 24 h after surgery) were randomly evaluated twice (one-month interval) by one evaluator for each language unaware of the pain condition. After watching each video, the evaluators scored the unidimensional, UFEPS-SF and Glasgow composite multidimensional feline pain scales. Statistical analyses were carried out using R software for intra and interobserver reliability, principal component analysis, criteria concurrent and predictive validities, construct validity, item-total correlation, internal consistency, specificity, sensitivity, the definition of the intervention score for rescue analgesia and diagnostic uncertainty zone, according to the receiver operating characteristic (ROC) curve.

Results

UFEPS-SF intra- and inter-observer reliability were ≥0.92 and 0.84, respectively, for all observers. According to the principal component analysis, UFEPS-SF is a unidimensional scale. Concurrent criterion validity was confirmed by the high correlation between UFEPS-SF and all other scales (≥0.9). The total score and all items of UFEPS-SF increased after surgery (pain), decreased to baseline after analgesia and were intermediate at 24 h after surgery (moderate pain), confirming responsiveness and construct validity. Item total correlation of each item (0.68-0.83) confirmed that the items contributed homogeneously to the total score. Internal consistency was excellent (≥0.9) for all items. Both specificity (baseline) and sensitivity (after surgery) based on the Youden index was 99% (97-100%). The suggestive cut-off score for the administration of analgesia according to the ROC curve was ≥4 out of 12. The diagnostic uncertainty zone ranged from 3 to 4. The area under the curve of 0.99 indicated excellent discriminatory capacity of UFEPS-SF.

Conclusions

The UFEPS-SF and its items, assessed by experienced evaluators, demonstrated very good repeatability and reproducibility, content, criterion and construct validities, item-total correlation, internal consistency, excellent sensitivity and specificity and a cut-off point indicating the need for rescue analgesia in Chinese, French, English, German, Italian, Japanese, Portuguese and Spanish.

Development and preliminary validation of a pain scale for ophthalmic pain in horses: The Equine Ophthalmic Pain Scale (EOPS)

The purpose of this study was to describe the development and preliminary validation of a composite pain scale, called the Equine Ophthalmic Pain Scale (EOPS), to assess ocular pain in horses. Indicators associated with ocular pain were selected and classified as behavioural, physiological or ocular expressions. Eight horses diagnosed with ocular or adnexa diseases that required medical or surgical treatment were enrolled in the study (group P). The developed EOPS was applied at the baseline (T0) and 1 week later (T7). Moreover, the EOPS was applied twice, 1 week apart, to 15 healthy control horses (group C). Videos of 60-80 s duration of all assessments were retrospectively analysed by seven masked observers, who scored items included in the behavioural and ocular expression categories of the EOPS. The inter- and intra-observer reliability was excellent (intraclass correlation coefficients ≥0.75) for most of the scored items. Cronbach's alpha (0.76) indicated that the EOPS had good internal consistency. The total score (TS), calculated as the sum of all scores, differed between groups C and P at T0 (P < 0.001) and reduced after medical/surgical treatment in group P (P = 0.017), indicating the responsiveness of the EOPS. Moreover, the area under the curve (AUC=0.918, 95% confidence interval=0.815-1.000; P < 0.001) indicated that the EOPS was very accurate for distinguishing healthy from pathological animals. Sensitivity and specificity of EOPS to identify horses with ocular pathology (at the optimal cut-off, i.e. TS≥7) were 81.3% and 100.0%, respectively. However, 'overall behaviour', 'position inside the box', 'ear movements' and 'head position' items as well as physiological parameters, showed sub-optimal reliability, consistency and/or item-total correlation, suggesting that there is still room to improve this composite scale.

Development of the Bristol Rabbit Pain Scale (BRPS): A multidimensional composite pain scale specific to rabbits (Oryctolagus cuniculus)

A species-specific composite pain scale is a prerequisite for adequate pain assessment. The aim of this study was to develop a multidimensional pain scale specific to rabbits (Oryctolagus cuniculus) called the Bristol Rabbit Pain Scale (BRPS). The scale was developed over five phases using a unique combination of methods: focus groups and behavioural observation. The first two phases aimed at identifying descriptors to describe a rabbit in pain, and then reducing their number, both using focus groups. A total of 72 pain descriptors were grouped under six categories (Demeanour, Posture, Facial expression, Attention to the painful area, Audible and Other) and 'No pain' descriptors were added. The third phase aimed to confirm, through video observation of rabbits, the categories and descriptors previously described, to reject those terms that were ambiguous, and identify any new descriptors that had not been included in the previous list of descriptors. This led to the rejection of the categories Audible and Attention to the painful area and of 34 descriptors. Seven new descriptors were identified. The last two phases constructed the final format of the BRPS by refining the categories, ranking the descriptors on an ordinal scale and testing the internal reliability of the scale using Cronbach's alpha test. This led to a composite pain scale of six categories (Demeanour, Posture, Locomotion, Ears, Eyes and Grooming) with four intensities of pain (0, 1, 2, and 3), a total score of 0-18, and a high Cronbach's alpha coefficient (alpha = 0.843). This BRPS fills an important gap in the field of rabbit medicine and has the potential to improve the assessment and management of pain in rabbits providing veterinary professionals with a novel multidimensional pain assessment tool. Further studies will investigate the clinical utility, validity and reliability of the BRPS.

Spontaneous Behaviors of Post-Orchiectomy Pain in Horses Regardless of the Effects of Time of Day, Anesthesia, and Analgesia

This prospective and longitudinal study aimed to identify spontaneous post-orchiectomy pain behaviors in horses regardless of the effects of anesthesia, analgesia, and recording time of day. Twenty-four horses divided into four groups were submitted to: inhalation anesthesia only (GA), or combined with previous analgesia (GAA), or orchiectomy under pre (GCA), or postoperative (GC) analgesia. The data obtained from the subtraction of frequency and/or duration of 34 behaviors recorded during seven 60-min time-points in the 24 h after the anesthesia from those recorded in the mirrored time-points in the 24 h before the anesthesia (delta) were compared over time and among groups by Friedman and Kruskal-Wallis tests, respectively (p < 0.05). Time of day influenced the behaviors of walk, look out the window, rest the pelvic limb, and rest standing still. The only pain-related behaviors were decreased mirrored proportional differences in time spent drinking, and eating, and increased mirrored proportional differences in the frequency or duration of look at the wound, retract the pelvic limb, expose the penis, and look at the back of the stall. In conclusion, confounding factors rather than pain may influence several suggestive pain-related behaviors documented in the literature.