Assessment of potential maladaptive pain in dogs with elbow osteoarthritis using a von Frey aesthesiometer.

BACKGROUND: This study aimed to investigate the possible presence of maladaptive pain in the thoracic limbs of dogs with elbow osteoarthritis (OA) using an electronic von Frey aesthesiometer (eVFA). METHODS: Twenty-eight client- and staff-owned dogs (OA, n = 14; controls, n = 14) were enrolled in the study. Every dog underwent a full orthopaedic examination, and then five von Frey measurements were obtained from each carpal pad of each dog. A maximum test threshold of 400 g was set and approved by an ethics committee. RESULTS: eVFA thresholds were significantly lower (p < 0.001) in dogs with OA (median 248 g, range 128-369 g) than in control dogs (median 390 g, range 371-400 g). In the OA group, the sensory threshold was significantly lower (p = 0.048) in the more severely affected limb than the less severely affected limb. LIMITATION: The low maximum threshold required for ethical approval may influence the variability in the control group. CONCLUSIONS: Dogs with elbow OA had significantly lower sensory thresholds than control dogs, which is compatible with the presence of maladaptive pain, potentially due to central sensitisation. Further research is required to evaluate the potential use of the eVFA for monitoring clinical progression and treatment response in dogs with elbow OA.

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.

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.

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.

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.

Retrospective assessment of tolerability and efficacy of zoledronate in the palliative treatment of cancer-bearing dogs.

Zoledronate is a bisphosphonate frequently used for the treatment of hypercalcaemia of malignancy and tumour-associated bone pain in dogs, however, there is a paucity of information regarding its use in veterinary medicine. The aim of this retrospective study was to report the tolerability of zoledronate in the palliative treatment of cancer-bearing dogs and secondarily to to assess the efficacy of zoledronate for the treatment of hypercalcaemia of malignancy. Thirty-seven dogs (22 with tumour-associated bone pain and 15 with hypercalcaemia of malignancy) that received 114 zoledronate infusions were included. Tolerability was assessed by the absence of post-zoledronate hypocalcaemia or other adverse events as defined by Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events criteria. Efficacy was assessed by comparison of available ionized calcium levels before and after zoledronate administration in hypercalcaemic dogs. In 79% of zoledronate infusions, no adverse events were reported. The majority of adverse events which occurred in the other 21% of infusions could be attributed to concurrent chemotherapy or the underlying neoplastic disease. There was a small but significant increase in creatinine following treatment with zoledronate, however, none of the dogs developed clinically significant renal disease. In eight hypercalcaemic dogs with available ionized calcium following zoledronate administration, ionized calcium decreased rapidly within 7 days following treatment with zoledronate. Zoledronate is well-tolerated with few recorded adverse events, however, monitoring of serum creatinine is advised. Zoledronate seems to be effective in the treatment of hypercalcaemia of malignancy.

The impact of COVID-19 on access to canine integrative medical care in Michigan, USA, and Ontario and British Columbia, Canada.

OBJECTIVE: To determine the effects of the COVID-19 associated restrictions on the ability of owners in Michigan (MI), USA versus Ontario (ON) and British Columbia (BC), Canada, to obtain care for their chronically painful dogs. STUDY DESIGN: Cross-sectional survey. POPULATION: A total of 90 owners met the inclusion criteria for the study. METHODS: An anonymous electronic survey was distributed to owners at four veterinary integrative medicine (IM) clinics during July and August 2020. Two clinics in MI and one each in ON and BC were recruited. Owners were asked about availability of IM care preceding and during COVID-19 restrictions and their opinions of the impact of COVID-19 on their dog's health. The survey asked where owners sought care for their dogs, types of chronic conditions treated, therapeutic modalities used, and if owners had a medical background. Comparisons were made within and between groups. Thematic analysis, Fisher's exact test, chi-square analyses, McNemar's and Wilcoxon signed-rank tests for paired comparisons were performed (p < 0.05). RESULTS: During COVID-19 restrictions, access to IM care was better for dogs in ON and BC than in MI (p < 0.001). The negative effect of the pandemic restrictions to IM care on quality of life was perceived greater by owners in MI than those in ON and BC (p < 0.001). The owners' medical backgrounds had no effect on attempts to access care during this time (p = 0.76). CONCLUSIONS AND CLINICAL RELEVANCE: The results suggest that a widespread disease in humans had an adverse impact on animal welfare. Providers of veterinary care should use this experience to establish protocols to ensure continuity of care for chronically painful animals in the event of a similar situation in the future.

Recognition and Assessment of Pain-Related Behaviors in Avian Species: An Integrative Review.

The appropriate recognition and assessment of pain in animals is an essential tool that can be used by veterinary professionals, rehabilitators, household caregivers, and others to provide supportive care and analgesia to patients. Although the use of behavioral, postural, and facial changes to recognize pain have been studied in popular domestic species such as dogs (Canis lupus familiaris), cats (Felis catus), and rabbits (Oryctolagus cuniculus), very little is known relative to avian species. The purpose of this article is to provide a literature review comprising structured searches on the topic of avian pain recognition. The emphasis of the searches were based on the behavioral and postural alterations that have thus far been explored. The literature review was performed in the months of August-September 2020 over 5 online databases: MEDLINE/ PubMed, CAB Direct, Biosis, Zoological Record, and Scopus. Additional "snowballing" was incorporated by looking at the references and articles that cited the 126 articles from the initial abstract and full-text screening. Of the 194 full-text articles reviewed, 132 sources of literature were included in the final analysis. From these 132 sources of literature, 31.8% were general review articles in which avian pain behaviors were described irrespective of species, with others being specific to a particular species (chickens 47.8%, turkeys 7.6%, parrots 3.8%, pigeons [Columba livia] 3%, raptors 3%, and "other" 3%-2 on ducks, 1 on emus [Dromaius novaehollandiae], and 1 on Eurasian blue tits [Cyanistes caeruleus]). Pain stimulus varied depending on species, although the vast majority of the pain stimuli involved welfare issues such as beak trimming, limb abnormalities, and keel bone fractures in chickens. Although information regarding this topic remains limited for many avian species, this review provides a more thorough understanding of behavioral indicators of pain in species such as chickens, turkeys, psittacines, pigeons, raptors, and select others. It is the hope that this review will motivate further interest and future analgesia research for the improvement of avian welfare.

Measurement properties of grimace scales for pain assessment in nonhuman mammals: a systematic review.

ABSTRACT: Facial expressions of pain have been identified in several animal species. The aim of this systematic review was to provide evidence on the measurement properties of grimace scales for pain assessment. The protocol was registered (SyRF#21-November-2019), and the study is reported according to the PRISMA guidelines. Studies reporting the development, validation, and the assessment of measurement properties of grimace scales were included. Data extraction and assessment were performed by 2 investigators, following the COnsensus-based Standards for the Selection of Health Measurement INstruments guidelines. Six categories of measurement properties were assessed: internal consistency, reliability, measurement error, criterion and construct validity, and responsiveness. Overall strength of evidence (high, moderate, and low) of each instrument was based on methodological quality, number of studies, and studies' findings. Twelve scales for 9 species were included (mice, rats, rabbits, horses, piglets, sheep or lamb, ferrets, cats, and donkeys). Considerable variability regarding their development and measurement properties was observed. The Mouse, Rat, Horse and Feline Grimace Scales exhibited high level of evidence. The Rabbit, Lamb, Piglet and Ferret Grimace Scales and Sheep Pain Facial Expression Scale exhibited moderate level of evidence. The Sheep Grimace Scale, EQUUS-FAP, and EQUUS-Donkey-FAP exhibited low level of evidence for measurement properties. Construct validity was the most reported measurement property. Reliability and other forms of validity have been understudied. This systematic review identified gaps in knowledge on the measurement properties of grimace scales. Further studies should focus on improving psychometric testing, instrument refinement, and the use of grimace scales for pain assessment in nonhuman mammals.

Assessment of pain associated with bovine respiratory disease and its mitigation with flunixin meglumine in cattle with induced bacterial pneumonia.

Pleuritic chest pain from bacterial pneumonia is often reported in human medicine. However, studies investigating pain associated with bovine respiratory disease (BRD) are lacking. The objectives of this study were to assess if bacterial pneumonia elicits a pain response in calves with experimentally induced BRD and to determine the analgesic effects of transdermally administered flunixin. A total of 26 calves, 6-7 mo of age, with no history of BRD were enrolled into one of three treatment groups: 1) experimentally induced BRD + transdermal flunixin at 3.3 mg/kg twice, 24 h apart (BRD + FTD); 2) experimentally induced BRD + placebo (BRD + PLBO); and 3) sham induction + placebo (CNTL + PLBO). Calves induced with BRD were inoculated with Mannheimia haemolytica via bronchoalveolar lavage. Outcomes were collected from -48 to 192 h post-treatment and included serum cortisol, infrared thermography, mechanical nociceptive threshold, substance P, kinematic gait analysis, visual analog scale (VAS), clinical illness score, computerized lung score, average activity and rumination level, prostaglandin E2 metabolite, plasma serum amyloid A, and rectal temperature. Outcomes were evaluated using either a generalized logistic mixed model for categorical variables or a generalized linear mixed model for continuous variables. Right front force differed by treatment (P = 0.01). The BRD + PLBO had lower mean force applied to the right front limb (85.5 kg) compared with BRD + FTD (96.5 kg; P < 0.01). Average VAS differed by a treatment by time interaction (P = 0.01). The VAS scores differed for BRD + PLBO at -48 (3.49 mm) compared with 168 and 192 h (13.49 and 13.64 mm, respectively) (P < 0.01). Activity for BRD + PLBO was higher at -48 h (27 min/h) compared with 48, 72, 120, and 168 h (≤ 22.24 min/h; P < 0.01). Activity differed by a treatment by time interaction (P = 0.01). Activity for BRD + FTD was higher at -48 and 0 h (28.2 and 28.2 min/h, respectively) compared to 48, 72, 96, and 168 h (≤23.7 min/h; P < 0.01). Results show a combination of reduced activity levels, decreased force on the right front limb, and increased VAS pain scores all support that bacterial pneumonia in cattle is painful. Differences in right front force indicate that flunixin transdermal may attenuate certain pain biomarkers in cattle with BRD. These findings suggest that BRD is painful and analgesic drugs may improve the humane aspects of care for cattle with BRD.

Assessment of Veterinary Students' Responses to Questions Regarding Small Animal Pain Recognition and Analgesic Treatment Options.

Pain recognition and treatment in companion animals are important aspects of veterinary medicine, yet the teaching of these concepts may not be adequate at all academic institutions. This study was designed to evaluate veterinary students' ability to recall signs of pain and specific analgesic drugs in dogs and cats. We hypothesized that students in the fourth, or final, year of their veterinary curriculum would have a better understanding of pain recognition and be able to recall more analgesic options. A brief, voluntary, and anonymous open question survey was made available to all veterinary students, years 1 to 4, at our institution. The questions included, "How does a cat/dog show signs of pain?" and "What pain medications are used in cats/dogs?" Survey responses were collated according to the students' year in the curriculum, and the most common responses for signs of pain and analgesic medications recalled by the students in both the cat and dog were compared for significant differences. Results showed that students in the class of 2017 (seniors) had no superior recall of analgesic medications or recognition of pain in cats or dogs compared to the other classes. Vocalization was the most common sign of pain recalled with at least 50% responses from all classes. Carprofen was the most commonly recalled analgesic for dogs (the difference between classes, p = .04). Meloxicam was the most commonly recalled analgesic for cats (the difference among classes, p < .001). Based on these results, areas of improvement were identified for our analgesic curriculum.

Preliminary survey of the attitudes of Brazilian scientists towards pain management and assessment in animals used in science.

OBJECTIVE: To investigate the current scenario in Brazil regarding pain assessment and control in experimental animals. STUDY DESIGN: Prospective survey. METHODS: A confidential questionnaire was available online and sent by e-mail to Brazilian scientists working with animal experimentation in Brazil. Data collection was conducted from October 2016 to October 2017. The exclusion criteria included blank questionnaires or with <80% completed responses, researchers not performing experiments involving animals and foreign scientists. RESULTS: A total of 96 questionnaires from 104 respondents were analyzed. The Fisher's exact test showed a disparity between the proportions of scientists who recognized the importance of analgesia and their application of analgesic techniques in painful procedures (p < 0.0003), and also for the researchers who assumed that experiments inflicted pain and their classification of the degree of invasiveness (p < 0.0001), indicating their insufficient knowledge of these topics. Overall, 77% of institutions did not offer specific training to assess pain in experimental animals, and 24% of respondents had no training to work with animal experimentation. In total, 62% of the studies inflicted pain, 48% of respondents used pain scales, and the drugs administered most frequently for pain management were morphine (44%), meloxicam (43%) and tramadol (37%); 15% of respondents did not include analgesics even though their studies inflicted pain. Commonly used animals were rats (33%), mice (29%) and rabbits (8%). CONCLUSIONS AND CLINICAL RELEVANCE: The results of this preliminary survey indicated that in Brazil there is a gap in the knowledge and training on pain assessment and management of experimental animals. Therefore, there is a necessity for an educational program to prepare and train scientists to assess and manage pain in laboratory or experimental animals. Further studies using a psychometrically validated survey instrument are warranted.

Prevalence and management of pain in dogs in the emergency service of a veterinary teaching hospital.

A prospective, observational, cross-sectional study documenting the prevalence of pain in dogs presented to the emergency service of a veterinary teaching hospital and their handling (times to triage, examination, treatment) was conducted. Pain was assessed and compared using a validated and an unvalidated pain assessment scale. Sedation was monitored using a validated scale. A first evaluation was completed in 109 dogs. A second evaluation was completed for 95 dogs: 36 (38%) were identified as painful and 53% (19/36) were provided analgesia in the clinic. The remainder either did not receive analgesia (6/36, 17%) or were prescribed an analgesic for administration at home (11/36, 31%). Of dogs receiving analgesia in the clinic, most showed a decrease in pain score (15/19, 79%). Pain assessment scales were positively correlated (r = 0.69, P < 0.0001) but the unvalidated scale was insensitive in discriminating changes. Between painful and non-painful dogs, progression did not differ: admission to treatment [P = 0.96, 95% confidence interval (CI): -23 to 22 minutes] and examination to treatment (P = 0.73, 95% CI: 14 to 20 minutes). Suboptimal analgesic use suggests focused training in pain assessment and analgesic use guided by a validated pain assessment scale, is warranted.

Prévalence et gestion de la douleur chez des chiens présentés au service d'urgence d'un hôpital d'enseignement vétérinaire. Une étude prospective, observationnelle et transversale a été réalisée pour documenter la prévalence de la douleur chez les chiens présentés au service d'urgence d'un hôpital universitaire vétérinaire ainsi que leur gestion (délai pour le triage, examen et traitement). Une échelle validée d'évaluation de la douleur a été utilisée pour évaluer la douleur à l'admission et suivant le traitement en clinique. A titre de comparaison, une échelle non validée d'évaluation de la douleur a également été utilisé et le degré de sédation a été documenté à l'aide d'une échelle de sédation validée. Une première évaluation a été complétée chez 109 chiens. Sur les 95 chiens pour lesquels une deuxième évaluation a été complétée, 36 (38 %) ont été identifiés comme étant en douleur et 53 % (19/36) ont reçu de l'analgésie en clinique. Les chiens restants n'ont soit pas reçu d'analgésie (6/36, 17 %) ou ont reçu une prescription pour un traitement analgésique à la maison (11/36, 31 %). Pour les chiens ayant reçu un traitement analgésique en clinique, la grande majorité ont démontré une diminution de leur score de douleur (15/19, 79 %). Une corrélation positive entre les deux échelles d'évaluation de la douleur était présente (r = 0,69, P < 0,0001), mais l'échelle non validée n'était pas sensible pour distinguer les changements de score de douleur. Il n'y avait pas de différence significative entre les chiens en douleur et non en douleur concernant le délai entre l'admission et le traitement (P = 0,96, 95 % CI : ­23 à 22 minutes) ou entre l'examen et le traitement (P = 0,73, 95 % CI : 14 à 20 minutes). L'administration d'analgésie était suboptimal dans la population étudiée, suggérant qu'un entraînement ciblé pour reconnaître et traiter la douleur à l'aide d'une échelle validée est recommandé.(Traduit par Dr Frédérik Rousseau-Blass).

Intraperitoneal and incisional analgesia in small animals: simple, cost-effective techniques.

The World Small Animal Veterinary Association Global Pain Council (WSAVA-GPC) has recently published its first "capsule review" by Monteiro et al. These are short articles that present a brief assessment of the scientific evidence and practical recommendations on important, and sometimes controversial, subjects in pain management. The capsules will be published regularly in the Journal of Small Animal Practice, the official journal of the WSAVA. This second article discusses the use of intraperitoneal and incisional analgesia in small animal practice, including their limitations and recommendations by the authors.

Short communication: Assessment of disbudding pain in dairy calves using nonlinear measures of heart rate variability.

The purpose of this study was to evaluate whether pain-related stress caused by disbudding could be detected using nonlinear measures of heart rate variability (HRV). Twenty-five female Holstein calves (4-7 wk of age) were randomly assigned to 1 of 3 treatments: (1) sham disbud (SHAM; n = 9), (2) disbud with lidocaine-meloxicam pain mitigation (MED; n = 8), or (3) disbud without pain mitigation (NoMED; n = 8). Heart rate variability (sample entropy, percentage determinism, percentage recurrence, or mean length of diagonal lines in a recurrence plot) was recorded on d -1, 0, 1, 3, and 5 relative to the experimental procedure, with disbudding taking place on d 0. The short-term detrended fluctuation analysis scaling exponent was greater in MED calves than in SHAM calves, indicating a greater stress response to the disbudding procedure regardless of pain mitigation. These results indicate that calves in the MED group may have experienced pain-related stress as a result of the disbudding procedure. The remaining nonlinear HRV measures did not differ by treatment. Future research on this topic should address additional potential confounding factors, such as the effect of pain-mitigating drugs on autonomic function or the influence of the autonomic nervous system on wound healing, that may prohibit HRV measurement as an indicator of disbudding pain severity.

An Objective Assessment of the Effect of Anesthetizing the Median Nerve on Lameness Caused by Pain in the Cubital Joint.

The median nerve, along with the ulnar nerve, is often anesthetized when performing a lameness examination in horses. Because of the close proximity of the median nerve to the cubital joint, proximal migration of local anesthetic might ameliorate pain originating from the cubital joint. The objective of this study was to determine if a median nerve block will ameliorate lameness caused by pain in the cubital joint. A forelimb lameness was induced in six healthy horses by injecting 100 ng of recombinant equine interleukin 1 beta (IL-1ß) into the cubital joint. The median nerve of the lame leg was anesthetized using 10 mL of 2% mepivacaine hydrochloride. A successful median nerve block was confirmed by loss of skin sensation at the medial aspect of the pastern and typical changes in thermographic images. Gait was assessed before and at 20, 40, and 60 minutes after the median nerve block using an inertial sensor-based motion analysis system (Lameness Locator; Equinosis LLC, Columbia, MO). A full-factorial repeated measures analysis of variance was used to compare treatment effect across time. IL-1ß administration resulted in significant transient lameness in all horses (P < .0001). The median nerve block was successfully performed in all horses and did not result in significant improvement (P = .32) of lameness as quantified by the total differential head vector sum. This result has relevant clinical application as it suggests when performing a lameness examination, it is unlikely that blocking the median nerve with 10 mL of local anesthetic will ameliorate pain originating from the cubital joint.

Assessment of Pain Associated with the Injection of Sodium Pentobarbital in Laboratory Mice (Mus musculus).

The AVMA Guidelines for the Euthanasia of Animals considers injection of barbiturates to be an acceptable method of euthanasia in rodents but states there is a potential for pain when administered intraperitoneally. This study examined the potential for pain in mice by assessing visceral pain after intraperitoneal administration and acute pain by using a paw-lick test. Male and female mice (n = 160) intraperitoneally received a euthanizing dose of sodium pentobarbital at a concentration of 5, 50, or 390 mg/mL and were observed for writhing, peritoneum-directed behaviors (PDB), loss of righting reflex, and time to death. Writhing was not observed in any animal. There was no significant difference in the number of mice exhibiting PDB or in the rate of PDB for responders receiving either saline or the 390-mg/mL solution. There was a significant treatment effect on time, with greater concentration and dose resulting in more rapid loss of righting reflex and death. In the second set of experiments, the same solutions were injected subcutaneously into the plantar hindpaw of male and female mice (n = 84). The number of responders, latency until the first lick, and the number of licks per responder were recorded. The number of responders was increased in the 50-mg/mL group; however, there was no difference in latency or the number of licks per responder. These results show that intraperitoneal injection of sodium pentobarbital for euthanasia in mice did not result in increased behavioral signs of pain, and animals lose consciousness more rapidly than the onset of pain seen in the pawlick test. Therefore, although sodium pentobarbital is capable of inducing inflammation, euthanasia through intraperitoneal administration is rapid and does not result in overt signs of pain when compared with injection of saline.

Leukocyte coping capacity chemiluminescence as an innovative tool for stress and pain assessment in calves undergoing ring castration.

Pain and stress assessment in animals is considered an imperative issue and also a difficult challenge. Unfortunately, no gold standard technique for pain and stress assessment in animals has been validated nowadays. A new tool to assess stress in animals consists of measuring the leukocyte coping capacity (LCC). The aim of this study was to evaluate the whole-blood LCC chemiluminescence as an innovative tool for stress and pain assessment in the bovine species undergoing ring castration. Twenty 2-mo-old male mix-breed Piemontese-Angus-Belgian Blue calves (Bos taurus) weighing 90 ± 4 kg were used. The animals were randomly allocated in 2 groups composed of 10 subjects each as follows: ring castration group (CAS) and sham castration group (SHAM). Blood drawing, scrotal and perineal temperature recording, scrotal lesion score, pain assessment, and LCC Chemiluminescence were performed at different time points, which were as follows: 1 h before castration/sham (-1 h), 30 min postcastration/sham (30 min), 3 d postcastration/sham (3 d), 7 d postcastration/sham (7 d), 14 d postcastration/sham (14 d). Results showed that in CAS LCC values significantly increased (P < 0.05) at 3 d and decreased at 7 d, whereas in SHAM, LCC values did not significantly vary between the study times. Significant differences in LCC values between CAS and SHAM were seen at 7 d (P < 0.0001). In the CAS group, scrotal lesion was scored as 0, 0, 3.8, 2.7, and 0.2 at -1 h, 30 min, 3 d, 7 d, and 14 d, respectively, whereas in SHAM, its score was 0 at every time point. Perineal temperatures did not vary throughout all the study times in both CAS and SHAM. Differences among the 2 groups were noted in scrotal temperatures only at 3, 7, and 14 d (P < 0.05). In CAS, the percentage of animals which obtained a pain score ≥ 1 was: 10% at -1 h, 30% at 30 min, 20% at 3 and 7 d, and 10% at 14 d, whereas in SHAM, no pain signs were noted at any time point. No significant difference between CAS and SHAM was recorded in cortisol blood level at any time point. No stress leukogram nor variation in neutrophil/lymphocyte ratio was noted at any of the time points in both CAS or SHAM. Our results suggest that ring castration might cause long-lasting pain in calves, but its magnitude is not easily detected by conventional methods. We argue that whole-blood LCC chemiluminescence might be a useful tool for detecting pain and stress in calves undergoing ring castration.

Assessment of daily activity patterns and biomarkers of pain, inflammation, and stress in lactating dairy cows diagnosed with clinical metritis.

The objectives of the present case-control study were to assess (1) daily activity patterns (lying time, number of steps, number of lying bouts, and lying bout duration), and (2) circulating concentrations of biomarkers of pain (substance P), inflammation (haptoglobin), and stress (cortisol) in lactating dairy cows diagnosed with clinical metritis. Lactating dairy cows (n = 200) from 2 commercial dairy herds were enrolled in the present study. Cows diagnosed with clinical metritis (n = 100) at 7 ± 3 d in milk were matched according to lactation and days in milk to cows without clinical metritis (NO-CM; n = 100). On study d 1, clinical metritis was diagnosed (using a Metricheck device, Simcro Tech Ltd., Hamilton, New Zealand) by the presence of watery, reddish, or brownish foul-smelling vaginal discharge, and blood samples were collected for assessment of circulating concentration of substance P, haptoglobin, cortisol, total calcium, ß-hydroxybutyrate, and blood cells. In addition, on study d 1 body condition of cows was visually assessed, and activity monitors were placed on the hind leg of a subset of cows (CM, n = 56; CON, n = 56) and were kept until study d 7. Cows showing any other signs of other diseases were not included in the study. Cows with clinical metritis tended to spend more time lying (CM = 628.92 min/d; NO-CM = 591.23 min/d) compared with NO-CM cows. Activity analysis by parity revealed that primiparous cows with clinical metritis spent more time lying compared with primiparous cows without clinical metritis. However, no differences in daily lying time were observed between multiparous cows with and without clinical metritis. Furthermore, cows in the CM group had a higher circulating concentration of substance P (CM = 47.15 pg/mL; NO-CM = 37.73 pg/mL) and haptoglobin (CM = 233.00 µg/mL; NO-CM = 99.98 µg/mL) when compared with NO-CM cows. Cows with clinical metritis had lower body condition score, and a greater proportion of cows in this group had hypocalcemia when compared with cows without clinical metritis. The circulating concentration of leukocytes and erythrocytes were decreased in cows with clinical metritis compared with cows without clinical metritis. Results from this study showed that concentrations of markers of inflammation, stress, pain, and activity were affected in cows diagnosed with clinical metritis; thus, strategies aimed to minimize the negative effects associated with clinical metritis may be required to improve the welfare of dairy cows.