Validation of the Donkey Pain Scale (DOPS) for Assessing Postoperative Pain in Donkeys

A retrospective comparison of postoperative outcomes in ovariectomised jennies (Equus asinus) treated with phenylbutazone or flunixin meglumine

BACKGROUND

Clinically, flunixin meglumine (FM) and phenylbutazone (PBZ) are preferentially selected for the treatment of visceral and musculoskeletal pain, respectively, in horses. In donkeys, there is no information to support or refute this conventional conjecture.

OBJECTIVES

To compare postoperative outcomes in a group of jennies treated with intravenous FM or oral PBZ.

ANIMALS

Fourteen jennies unilaterally ovariectomised by standing left flank laparotomy.

STUDY DESIGN

Retrospective cohort study.

METHODS

Data from medical records of ovariectomised jennies (case details, weight, non-steroidal anti-inflammatory drug [NSAID] protocol, surgery duration, operative sequence, anaesthesia protocol, physical examination findings and outcomes) were collected. From collated data, postoperative adverse events were defined as fever, tachycardia, tachypnea, inappetence, altered mentation, abnormal oral mucous membranes, bruxism, colic, incisional complications (i.e., drainage, oedema, peri-incisional emphysema and pain) and non-survival, then further divided into occurrence during the early (≤24 h) or late (>24 h) postoperative period for data analysis using R software. Chi-squared test was used to compare individual adverse events between groups (PBZ vs. FM) and moments (early vs. late). Significance was set at p ≤ 0.05.

RESULTS

PBZ treatment (8/14) was associated with (odds ratio, 95% confidence interval) more total (2.93, 1.97-4.36), early (3.01, 1.87-4.84) and late (2.69, 1.28-5.63) adverse events than FM treatment (6/14). Tachycardia (37.83, 2.21-646.66), tachypnoea (0.29, 0.13-0.66), altered mentation (2.78, 1.01-7.67), altered mucous membranes (18.38, 1.04-325.23), incisional oedema (44.33, 2.60-754.5) and incisional pain (47.78, 2.81-811.61) were significantly different between groups. Early adverse events significantly different between groups included tachycardia (50.2, 2.9-877.0), altered mentation (3.33, 1.08-10.29) and incisional pain (21.0, 1.2-374.5), with late adverse events being tachypnea (0.07, 0.01-0.62), incisional oedema (32.92, 1.85-584.28) and incisional pain (28.92, 1.62-515.68). Colic (2/8) and non-survival (1/8) were rare events that only occurred in the PBZ cohort and could not be further evaluated for differences.

MAIN LIMITATIONS

Small sample size; retrospective study; treatment bias; varied administration routes.

CONCLUSIONS

Oral PBZ may be inappropriate to use following abdominal surgery in donkeys.

CLINICAL RELEVANCE

More prospective and case-controlled studies are needed to evaluate the clinical efficacy of these two NSAIDs in donkeys.

Objective assessment of chronic pain in donkeys using the Donkey Chronic Pain Scale

OBJECTIVE

To clinically evaluate previously developed pain scales [Donkey Chronic Pain Composite Pain Scale (DCP-CPS), Donkey Chronic Pain Facial Assessment of Pain (DCP-FAP) and combined Donkey Chronic Pain Scale (DCPS)], including behavioural and facial expression-based variables, for the assessment of chronic pain in donkeys.

STUDY DESIGN

Prospective, blinded clinical study.

ANIMAL

A group of 77 donkeys (34 patients and 43 healthy control animals).

METHODS

Animals were assessed by two observers that were blinded to the condition of the animals.

RESULTS

Both DCP-CPS and DCP-FAP, and resulting combined DCPS scores, showed good interobserver reliability [intraclass correlation coefficient (ICC) = 0.91, 95% confidence interval (CI) = 0.86-0.95, p < 0.001; ICC = 0.71, CI = 0.50-0.83, p < 0.001 and ICC = 0.84, CI = 0.72-0.91, p < 0.001, respectively]. All scores (DCP-CPS, DCP-FAP and the resulting combined DCPS) were significantly higher for patients than for controls at all time points (p < 0.001 for all three scales). Sensitivity and specificity for identification of pain (cut-off value >3) was 73.0% and 65.1% for DCP-CPS, and 60.9% and 83.3% for DCP-FAP, respectively. For the combined DCPS, sensitivity was 87.0% and specificity 90.9% (cut-off value >6).

CONCLUSIONS AND CLINICAL RELEVANCE

Based on behavioural and facial expression-based variables, DCPS proved a promising and reproducible tool to assess different types of chronic pain in donkeys. The combination of behavioural and facial expression-based variables showed the best discriminatory characteristics in the current study. Further studies are needed for refinement of these tools.

Real-time and video-recorded pain assessment in beef cattle: clinical application and reliability in young, adult bulls undergoing surgical castration

Bovine pain assessment relies on validated behavioral scales related to normal and pain-related behaviors. This study investigated the reliability and applicability of real-time and video-recorded pain assessment, and their agreement, in young, adult bulls undergoing surgical castration. Ten Nelore and nine Angus bulls underwent general anesthesia and surgical castration. Three-minute real-time observations and simultaneous videos were recorded at - 48 h (M0), before sedation, under fasting (M1), after surgery, 3 h after sternal recumbency (M2), after rescue analgesia (M3) and at 24 h (M4). Animals received morphine (after M2), dipyrone (after M3), and flunixin meglumine after surgical castration (M4). Two trained evaluators assessed real-time (n = 95) and video-recorded time-points (n = 95) using the Unesp-Botucatu Cattle Pain Scale (UCAPS). Both assessment methods inferred 'very good' reliability (≥ 0.81) with minimal bias, however, video-recorded assessment (4.33 ± 2.84) demonstrated slightly higher scores compared to real-time (3.08 ± 2.84). The results from this study suggest that UCAPS can be used in real-time or video-recorded to assess pain and guide analgesic therapy in cattle.

Evaluation of a digital stethoscope for electrocardiographic recording in donkeys: Preliminary results

The digital stethoscope (DS) is a cost-effective single-lead digital stethoscope that allows simultaneous electrocardiographic (ECG) and phonocardiographic recordings on a smartphone. Despite its application in small animals and horses, there are currently no studies on its use in donkeys. The aim of this study was to evaluate the use of a new smartphone-based DS device in recording ECG tracings in donkeys. Standard base-apex lead ECG (sECG) and single-lead DS ECG (dECG) were simultaneously recorded for at least 30 s. Both sECG and dECG tracings were analysed by the same operator, recording heart rate, ECG waves and intervals, and the presence and duration of artefacts. Thirty-seven donkeys were included. The dECG tracings were interpretable in all the animals (100 %). The results showed perfect agreement between the sECG and dECG data for the classification of heart rhythm and P-wave polarity. Strong agreement was found in the evaluation of heart rate calculated manually and automatically by the smartphone app, QRS complex polarity, T wave polarity, and duration of the PR interval. However, no agreement was found in the evaluation of P wave duration, QRS complex duration and amplitude, and T wave duration and amplitude. In conclusion, although this is only a preliminary study, the DS was a valid, practical, and easy to use electrocardiographic tool for recording good-quality ECG tracings to assess the ECGs of donkeys in the field.

Pharmacotherapeutic monitoring of dipyrone in northeastern Brazilian donkeys (Equus asinus)

This study aimed to monitor the effects of dipyrone following multiple administrations in northeastern donkeys. Ten castrated male donkeys, aged 6.4 ± 3 years and weighing 130.6 ± 9.8 kg, were administered dipyrone (25 mg/kg IV) every 12 h, resulting in six administrations (D1 to D6) per animal. Blood samples were collected over a 72 h monitoring period. A validated UHPLC-MS/MS method was employed to determine the plasma concentrations of the 4- methylaminoantipyrine (4-MAA) and 4-aminoantipyrine (4-AA). The calculated pharmacokinetic variables of 4-MAA after D1 and D6 were, respectively: Cmax (μg/mL) = 163.60 ± 179.72 and 178.79 ± 196.94; T1/2beta (h) = 2.65 ± 0.65 and 3.37 ± 1.03; and AUC0-t (μg/mL × h) = 240.38 ± 130.87 and 373.52 ± 78.85. The same variables for 4-AA were: Cmax, (μg/mL) = 0.44 ± 0.27 and 0.90 ± 0.31, T1/2beta (h) = 14.77 ± 13.13 and 35.97 and AUC0-t (μg/mL × h) = 3.20 ± 0.43 and 27.73 ± 11.99. Concentrations of 4-MAA exceeded the minimum concentration required for 50% inhibition of cyclooxygenases 1 and 2. However, an accumulation of 4-AA, was observed. Further clinical studies are necessary to ascertain the implications of these findings on the pharmacodynamic response to dipyrone in northeastern donkeys.

Morphine in donkeys: Antinociceptive effect and preliminary pharmacokinetics

BACKGROUND

Morphine is the prototypical μ-opioid receptor agonist used to provide analgesia in veterinary species. Its effects are well-described in horses but not donkeys.

OBJECTIVES

To determine the antinociceptive effects of two doses of morphine in donkeys. To describe preliminary pharmacokinetic parameters of morphine in donkeys.

STUDY DESIGN

In vivo experiment.

METHODS

Eight adult castrated male donkeys were given intravenous (IV) 0.9% saline, morphine 0.1 mg/kg bwt (LDM), or morphine 0.5 mg/kg bwt (HDM) in a randomised order with a minimum 1-week washout period. Mechanical nociceptive thresholds (MNTs) were determined by a blinded investigator pre-injection and 15, 30, 45, 60, 90, 120, 150, 180, 210, 240, 300, and 360 min post-injection. Venous blood samples were collected pre-injection and 2, 5, 10, 15, 30, 45, 60, 90, and 120 min post-injection. Data were analysed using Friedman's test with Dunn's post hoc test for multiple comparisons. Pharmacokinetic parameters were calculated for the HDM treatment.

RESULTS

Baseline MNT was [median (interquartile range)] 8.9 (7.1-10.3) N and did not differ between treatments. Peak MNTs occurred at 60 min for both LDM (16.2 N) and HDM (25.0 N) treatments. MNTs after HDM treatment were higher than saline (p < 0.04) at 15, 60, 90, 120, 150, 180, 240, and 300 min post-injection. MNTs after LDM treatment were higher than baseline (p < 0.05) at 45 and 60 min post-injection. Terminal half-life for HDM was (mean ± SD) 51.0 ± 10.7 min, the volume of distribution at steady-state 2.07 ± 0.33 L/min and clearance 49.2 ± 4.16 ml * min/kg using noncompartmental analysis. The concentration of morphine-3-glucuronide (M3G) was higher than morphine-6-glucuronide (M6G) at all sampled time points.

MAIN LIMITATIONS

Short duration of plasma sampling for pharmacokinetic analysis; lack of objective measure of gastrointestinal function.

CONCLUSIONS

The HDM treatment provided mechanical antinociception in donkeys with no significant adverse effects.

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.

A Pilot Study on Behavioural and Physiological Indicators of Emotions in Donkeys

Recognizing animal emotions is critical to their welfare and can lead to a better relationship with humans and the environment, especially in a widespread species like the donkey, which is often prone to welfare issues. This study aims to assess the emotional response of donkeys through an operant conditioning task with two presumed different emotional contents. Specifically, a within-subject design including positive and negative conditions was conducted, collecting behavioural and physiological (heart rate variability and HRV) parameters. Facial expressions, postures, and movements were analysed by principal component analysis and behavioural diversity indexes (frequencies, activity budgets, richness, Shannon and Gini-Simpson). During the positive condition, both ears were held high and sideways (left: r = -0.793, p < 0.0001; right: r = -0.585, p = 0.011), while the ears were frontally erected (left: r = 0.924, p < 0.0001; right: r = 0.946, p < 0.0001) during the negative one. The latter was also associated with an increased tendency to walk (r = 0.709, p = 0.001), walk away (r = 0.578, p = 0.012), more frequent changes in the body position (V_{Body position} = 0, p = 0.022), and greater behavioural complexity (V_{Gini-Simpson Index} = 4, p = 0.027). As for HRV analysis, the root mean square of successive beat-to-beat differences (rMSSD) was significantly lower after the negative condition. These non-invasive parameters could be considered as possible indicators of donkeys' emotional state.

Pain Assessment and Acute Phase Response in Donkeys Submitted to Inguinal Orchiectomy

In most animals, pain can compromise physiological functions and delay healing so, rapid detection of pain through behavior and inflammatory reaction with biomarkers are necessary. This study aimed to evaluate pain, physiological variations and Acute Phase Proteins (APP) in donkeys undergoing orchiectomy technique by inguinal access. For this research, 15 male northeastern donkeys kept in extensive management were selected, with a mean age of 4.5±3.1 years. All animals had the same anesthetic protocol, using dissociative anesthesia and local block with lidocaine, followed by orchiectomy by inguinal access. Due to their predisposition to complications, the inguinal technique is the most indicated to minimize complications and excessive inflammation in donkeys' orchiectomy, the donkeys were evaluated regarding behavioral assessment of pain, hematological parameters, APP and the surgical wound, during 0 hour, 24 hours, 48 hours and 72 hours. As for the physiological parameters and APP, no significant differences were observed between times, due to the use of nonsteroidal antiinflammatory drugs. In the macroscopic evaluation of the surgical wound, it was observed that there were no significant differences between the times, with animals presenting mean scores of 1.8±0.414, in 48 hours 1.6 ± 0.507, and in 72 hours 1.6 ± 0.507. Most animals had mild to moderate edema in the scrotum and foreskin regions. As for pain assessment, the average scores were between 2 and 3, representing mild and moderate pain, not requiring intervention. However, further research is needed to elucidate the behavior of PFAs in the face of variables and the creation of new pain scales for animals raised in an extensive system.

Reliability and Validity of UNESP-Botucatu Cattle Pain Scale and Cow Pain Scale in Bos taurus and Bos indicus Bulls to Assess Postoperative Pain of Surgical Orchiectomy

Pain assessment guides decision-making in pain management and improves animal welfare. We aimed to investigate the reliability and validity of the UNESP-Botucatu cattle pain scale (UCAPS) and the cow pain scale (CPS) for postoperative pain assessment in Bos taurus (Angus) and Bos indicus (Nelore) bulls after castration.

METHODS

Ten Nelore and nine Angus bulls were anaesthetised with xylazine-ketamine-diazepam-isoflurane-flunixin meglumine. Three-minute videos were recorded at -48 h, preoperative, after surgery, after rescue analgesia and at 24 h. Two evaluators assessed 95 randomised videos twice one month apart.

RESULTS

There were no significant differences in the pain scores between breeds. Intra and inter-rater reliability varied from good (>0.70) to very good (>0.81) for all scales. The criterion validity showed a strong correlation (0.76-0.78) between the numerical rating scale and VAS versus UCAPS and CPS, and between UCAPS and CPS (0.76). The UCAPS and CPS were responsive; all items and total scores increased after surgery. Both scales were specific (81-85%) and sensitive (82-87%). The cut-off point for rescue analgesia was >4 for UCAPS and >3 for CPS.

CONCLUSIONS

The UCAPS and CPS are valid and reliable to assess postoperative pain in Bos taurus and Bos indicus bulls.

Efficacy of transdermal flunixin in mitigating castration pain in piglets

Castration is a painful procedure performed in swine and to date, there are no approved products available in the US to alleviate this pain. Previous work evaluating the efficacy of flunixin meglumine has shown promise in mitigating pain in swine, but no work to date has evaluated transdermal flunixin efficacy in mitigating castration pain in piglets. Therefore, the objective of this study was to evaluate the efficacy of transdermal flunixin (TDF) in mitigating castration pain utilizing a previously validated behavioral pain scale. A total of 98 Large White x Duroc cross male piglets from 98 litters were enrolled in this study. Piglets were randomly assigned to the following treatments: (1) TDF plus castration (3.33 mg/kg; CF; n = 24), (2) TDF plus sham castration (3.33 mg/kg; SF; n = 26), (3) topical physiological saline plus sham castration (S; n = 24), or (4) topical physiological saline plus castration (C; n = 24). All treatments were administered 24 h prior to castration. Four-min continuous videos clips were collected 24 h before castration (−24 h), immediately post-castration (0 h), and 24 h post-castration (+24 h). Video clips were then observed and scored by one trained observer using a 4-point pain scale (score 0–3) encompassing the five behavioral domains of the pig acute pain scale (UPAPS). Total pain score averages were analyzed as repeated measures by analysis of variance applying a multilevel model. The UPAPS effectively distinguished varying levels of painful and non-painful states in castrated piglets as observed via deviations in total pain scores across timepoints (P &lt; 0.0001), treatment (P &lt; 0.001) and treatment*timepoint (P &lt; 0.0001). Immediately post-castration (0 h), piglets in the C and CF group demonstrated greater total average pain scores than piglets in the S (P &lt; 0.03) and SF (P &lt; 0.01) groups and castrated piglets treated with TDF demonstrated lower total pain scores (P &lt; 0.05) and required less analgesic intervention immediately post-castration compared to castrated piglets receiving no treatment (P &lt; 0.0001). For C group 54% required rescue analgesia compared to 29%, 8% and 0% for CF, SF and S piglets respectively. Future work should evaluate implementation of this pain management protocol on a wide scale commercial farm setting.

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.