Humane Euthanasia Research Articles

Interactive euthanasia training program for swine caretakers; a study on program implementation and perceived caretaker knowledge

Implementing timely and humane euthanasia on-farm is of key importance for safeguarding animal welfare. Equally important is the skill, attitude, and knowledge among caretakers to successfully perform euthanasia on-farm. This study investigated the potential of an interactive euthanasia training program in conjunction with a survey designed to investigate attitudes and perceived knowledge of the Common Swine Industry Audit euthanasia guidelines. The survey results showed that caretakers self-reported improved knowledge of industry expectations immediately post training compared to their perceived knowledge pre-training. This study provides insight regarding interactive training programs and identifies variation in perceived euthanasia knowledge within swine caretaker demographics.

Tensile strength and early healing of self-locking and surgeon's knots.

To compare the biomechanical properties and healing of ventral midline celiotomies (VMC) closed with a self-locking knot combination and forwarder start and Aberdeen end (F-A) vs a traditional knot combination and surgeon's start and end (S-S). In vivo, experimental. Twenty-one horses. Fourteen horses underwent VMC, which was closed with either an F-A (n = 7) or an S-S (n = 7) knot combination. Incisions were subjectively graded by masked evaluators for dehiscence, edema, and drainage. Biomechanical testing was performed on three abdominal segments, and histology was performed on one segment from each animal after humane euthanasia 10 days post-VMC. The abdominal wall of control horses (n = 7, no celiotomy) was collected for biomechanical testing. Forwarder start and Aberdeen end and S-S horses had less tensile strength compared with control horses (P ≤ .001). No differences were detected between treatment groups for any variable evaluated, including tensile strength (P = .975), location of failure (P = .240), and histologic healing at the knot (P = .600). Closure of VMC with self-locking knots resulted in biomechanical and healing features similar to those with a traditional closure technique, with neither restoring the tensile strength of the linea alba. Results of this study provide evidence to support a clinical trial to evaluate long-term performance of the F-A self-locking knot closure in horses.

Humane Euthanasia of Guinea Pigs (Cavia porcellus) with a Penetrating Spring-Loaded Captive Bolt.

Simple SummaryVarious euthanasia methods are currently employed for guinea pigs at their experimental or humane endpoint; however, many have significant limitations or negative animal welfare implications. Captive bolt euthanasia has been used in the guinea pig meat industry but has not been explored in a research setting. This work aimed to investigate the use of a penetrating spring-loaded captive bolt gun as a refinement to guinea pig euthanasia in research. The study found that when compared to blunt force trauma, the captive bolt procedure performed well against all parameters of humane slaughter of production animals and appears to be a feasible refinement for animal welfare.Guinea pigs (Cavia porcellus) have been used in research since the 19th century to collect data due to their physiological similarities to humans. Today, animals perform a vital role in experiments and concerns for laboratory animal welfare are enshrined in the 3R framework of reduction, refinement and replacement. This case study explores a refinement in humane euthanasia of guinea pigs via the use of an irreversible penetrating spring-loaded captive bolt (CB). Penetrating spring-loaded CB stunning for euthanasia (CBE) was performed on 12 guinea pigs with the parameters for humane slaughter of production animals in order to assess the suitability of this method of euthanasia in contrast to blunt force trauma (BFT). All 12 of the guinea pigs were rendered immediately unconscious with excellent experimental tissue quality collection, high repeatability of results and operator (n = 8) preference over BFT. Overall, CBE in guinea pigs appears to be a feasible refinement for animal welfare, human preference and improved tissue quality for experimental collection in settings where uncontaminated tissues are required.

Blood L-Lactate Concentration as an Indicator of Outcome in Roe Deer (Capreolus capreolus) Admitted to a Wildlife Rescue Center.

Simple SummaryRoe deer are among the most frequent wild animals admitted to rescue centers in Italy. Reasons for admission include trauma, predation, starvation, and imprinting, with the final aim of hospitalization being full recovery and release into the wild for all cases. An accurate triage procedure is vital for predicting the outcome, to avoid unnecessary time spent in captivity, and an excessive allocation of time and resources on animals with a minimal chance of recovery. Since lactacidosis is often associated with death in hospitalized animals, and has been associated with poor prognosis in humans and domestic animals, we proposed an evaluation of blood L-lactate using a rapid whole blood test in order to predict the outcome of hospitalized roe deer. A cut-off of 10.2 mmol/L was identified as the best, in order distinguish animals with minimal chance of surviving and release. For these animals, humane euthanasia should be considered as an option. Roe deer (Capreolus capreolus) are among the most frequent patients of rescue centers in Italy. Three outcomes are possible: natural death, euthanasia, or treatment and release. The aim of the present study is to propose blood L-lactate concentration as a possible prognostic biomarker that may assist veterinarians in the decision-making process. Sixty-three roe deer, admitted to one rescue center in the period between July 2018 and July 2019, were sampled and divided into 4 groups according to their outcome: (1) spontaneous death (17 cases), (2) humanely euthanized (13 cases), (3) fully recovered and released (13 cases), and (4) euthanized being unsuitable for release (20 cases). In addition, blood samples from 14 hunted roe deer were analyzed as controls. Whole blood lactate concentrations were measured with a point of care lactate meter. Differences among groups were close to statistical significance (p = 0.51). A cut-off value of 10.2 mmol/L was identified: all the animals with higher values died or were humanely euthanized. The results suggest that roe deer with lactatemia higher than 10.2 mmol/L at admission, have a reduced prognosis for survival during the rehabilitation period, regardless of the reason for hospitalization and the injuries reported. Therefore, humane euthanasia should be considered for these animals.

The World Small Animal Veterinary Association (WSAVA): List of Essential Medicines for Cats and Dogs.

The World Small Animal Veterinary Association (WSAVA): List of Essential Medicines for Cats and Dogs.

Cat Brain Neuroanatomy using Cryosectioning, Magnetic Resonance and Computed Tomography Imaging Modalities

Magnetic resonance imaging (MRI) and computed tomography (CT) imaging modalities are invaluable for the diagnosis and treatment of neurological diseases. This study aimed to correlate the anatomical sectional data of the cats’ brain to the sections obtained by both MRI and CT examination. The present work was conducted on four cats, 1-4 years old, weighing about (2.5 to 3.5) kg admitted to the hospital with terminal diseases not related to the nervous system. The anatomical sections were taken at intervals of 5 mm, on different planes such as sagittal, frontal and transverse. The sections were obtained, following humane euthanasia, from frozen heads and identified according to the previous literatures. The images from both MRI and CT were compared with those of the gross anatomy sections and different structures were identified. To identify arterial distribution in the brain, one cat was injected with red latex through the common carotid artery, frozen, and sectioned. For vascular imaging, the same cat was examined by MRI after intravenous injection of contrast media. The descriptions of the brain anatomy from the MRI and CT images will act as a basis for the diagnosis and treatment of different neurological diseases in cat. This will assist veterinarians and radiologists in the identification of various nervous lesions related to the brain.

Anatomical and histological observations on a musk ox brain (Ovibos moschatus)

Musk oxen are large tundra‐dwelling bovids that, when in rut, can strike heads at speeds around 30 mph. The wide base of their large horns armor their skull against such impacts, although it is unknown if they sustain brain trauma. There is no literature describing concussion, or other adverse repercussions of severe cranial contact in musk oxen. Our research explores the brain and skull anatomy of combative bovids, specifically focusing on whether these animals sustain brain injury after head‐butting, and if not, what features most likely provide protection. Achieving a better understanding of how these extreme animals may avoid brain injury will provide insight to develop strategies for the reduction of traumatic brain injury in humans.An archived brain of an adult male musk ox was used in this preliminary study. It had been collected after humane euthanasia and preserved in formalin following a goring injury in the wild where it had been observed clashing heads with another musk ox bull in the moments before its death. The brain was MR scanned and examined histologically for evidence of traumatic brain injury. The right hemisphere was fixed in paraformaldehyde (4%, buffered) and prepared using a variety of exploratory histological protocols, to investigate abnormalities in neurons, microglia, astrocytes, and blood vessels. Specifically, Tau protein, a biomarker found in the cerebrospinal fluid and in neurodegenerative lesions, was used to detect any brain trauma‐related cellular consequence of chronic or acute head clashing. Preliminary histological results indicate no apparent abnormalities. A high‐resolution 7‐T MRI scan additionally revealed no abnormal neuropathological changes. This brain being a single sample does not allow us to make sweeping assumptions. However, these preliminary investigations lead us to believe that musk oxen do not appear to suffer from chronic or acute brain trauma after head clashing. A more in‐depth exploration with a larger sample size is proposed to better understand the combination of anatomical structures contributing to brain protection in these animals.Support or Funding InformationNLA is a fellow of the Swiss National Science Foundation

Comparison of penetrating and non-penetrating captive bolt in an alternative occipital approach in calves

AbstractThe objective of this study was to describe the effect of penetrating or non-penetrating captive bolt using an occipital approach in 4-5 month old, Holstein steers weighing between 100-200 kg. Twelve calves were divided into two treatment groups; penetrating captive bolt (PCB; n = 6) and non-penetrating captive bolt (NPCB; n = 6). This sample size was chosen out of convenience and in conjunction with a separate study. Each calf was sedated with xylazine hydrochloride, then a captive-bolt device, outfitted with a standard penetrating bolt or a non-penetrating bolt, was placed flush on the dorsal midline of the cranium at the external occipital protuberance and aimed downward as though to intersect the intermandibular area. Following impact, indicators for loss of consciousness, such as respiration, righting response, corneal reflex, movement and vocalisation were recorded and characterised along with electrocardiogram and electroencephalogram recordings. After a 5-min observation period, all calves were administered potassium chloride. All calves experienced immediate and sustained loss of consciousness. The mean (± SEM) time to cessation of respiration was 60 (± 53.67) and 0 (± 0.0) s for PCB and NPCB, respectively. The mean time to cessation of convulsions was 310.4 (± 79.74) and 180.0 (± 60.24) s, respectively, and the mean number of convulsions was 2.75 (± 1.03) and 2.0 (± 0.837) for PCB and NPCB, respectively. Isoelectric EEG patterns were observed in 3/5 PCB and 3/4 NPCB with mean time to onset of isoelectric pattern in 69.0 (±52.24) and 113.5 (± 56.87) s. Both treatments induced a successful stun, which suggests these techniques are appropriate for humane euthanasia in calves of this age.

Collapse in a mare during standing sedation with a fatal outcome

A 6-year-old 559-kg Canadian Warmblood mare with lacerations over the neck and all four limbs was presented to the Western College Veterinary Medicine. Medical treatment and wound lavage was carried...

Effect of 3 Euthanasia Methods on Serum Yield and Serum Cortisol Concentration in Zebrafish (Danio rerio).

Zebrafish are an important model in neuroscience and developmental biology and are also an emerging model in hematology and immunology. Little information is available for zebrafish regarding the physiologic impact of different euthanasia methods and whether a chosen method of euthanasia can impact serum yield. These parameters could impact the choice of euthanasia method for a study. To that end, the current study compared 3 methods of adult zebrafish euthanasia and their effects on 3 distinct criteria; time to loss of opercular movement, volume of serum obtained, and serum cortisol concentration. Blood was collected using a postmortem tail amputation and centrifugation blood collection technique. Time to loss of opercular movement differed significantly among euthanasia methods, with animals undergoing rapid chilling displaying the shortest time (mean Rapid Chilling: 40 s; Benzocaine: 86 s; MS222: 96 s). All methods of euthanasia resulted in a comparable average serum yield (Rapid Chilling = 7.5 μL; Benzocaine = 8.5 μL; MS222 = 7.5 μL per fish). None of the euthanasia methods tested resulted in average cortisol concentrations above the reported physiologic range. Although no significant differences were observed in serum yield or serum cortisol concentration, rapid chilling remains the preferred method for painless, humane euthanasia.

Successful resection of an osteoma in a great horned owl (Bubo virginianus) with subsequent lack of regional feather regrowth

A free-living adult great horned owl (Bubo virginianus) was presented to a wildlife rehabilitation centre in Southern California with a firm, pedunculated mass arising from the caudal-dorsal border of the...

Encysted cyathostomin larval counts: Mucosal digestion revisited

Cyathostomins are pervasive equine parasites in horses across the world, and larval stages are known to cause the deadly disease larval cyathostominosis. The mucosal digestion technique is widely used for enumeration of encysted larval stages. Previous studies have investigated the spatial variation of encysted larvae, however current protocols lack a description of a standardized area from which to take the tissue sample. This study sought to evaluate spatial variation in encysted cyathostomin larval counts among the large intestinal organs and their subsections. Following humane euthanasia, ceca, ventral, and dorsal colons were harvested from 8 foals (aged 4–8 months) raised in an anthelmintic naïve parasitology research herd. Each organ was weighed and separated into 3 equal sections by length: the orad, intermediate, and aborad portions. From each of those sections, two 5% weight tissue samples were collected and digested to quantify the early third stage larvae (EL3) and late third stage larvae/fourth stage larvae (LL3/L4). A mixed model statistical analysis was carried out to evaluate for differences of larval counts among the different organs, sections, and the interaction term between the organs and sections. There were significant differences among organs (P < 0.0001), with the ceca having higher counts than the ventral and dorsal colons. However, there were no significant differences among the three defined organ sections (P = 0.1076). Coefficients of variation (CV) were all calculated to be greater than 1, suggesting a high level of variability among the samples; the least amount of variation can be found in the cecal data with a CV of 1.4024 compared with the ventral colon’s 1.529845 and dorsal colon’s 3.339135 within the respective organ. The following sections had the highest mean counts of encysted larvae: intermediate cecum, orad ventral colon, and aborad dorsal colon. Though only a portion of the results were significant, trends were observed and these should be investigated further in future studies and potentially employed in larvicidal efficacy evaluations.

Septic epiphysitis and sequestrum formation in the glenoid of the scapula in a five-month-old foal diagnosed by computed tomography

A five-month-old Connemara foal presented for acute-onset, severe left forelimb lameness with fever, neutrophilia and an elevated serum amyloid A concentration. Radiographs were suspicious of septic physitis of the proximal...

Is sex a biological variable in corneal wound healing?

Wound healing differs significantly between men and women in a tissue-dependent manner. Dermal wounds heal faster in women whereas mucosal wounds heal faster in men. However, the effect of sex as a variable in corneal wound healing is largely unknown. The primary objective of this study was to test whether sex is a biological variable in corneal wound healing activated by the trauma or injury using an established in vivo rabbit model with male and female New Zealand White rabbits. Corneal wounds in rabbits were produced by a single topical alkali (0.5N Sodium hydroxide) application. Serial slit-lamp, stereo biomicroscopy, and applanation tonometry evaluated corneal opacity, anterior segment ocular health, and intraocular pressure (IOP), respectively, at various times during the study. Fourteen days after alkali-wound, corneal tissues were collected after humane euthanasia to examine cellular and molecular wound healing parameters. Quantitative PCR (qPCR) and immunofluorescence were used to quantify changes in the extracellular modeling protein levels of alpha-smooth muscle actin (α-SMA), Fibronectin (FN), Collagen-I (Col-I), and Transforming growth factor beta 1 (TGFβ1) involved in corneal healing. Hematoxylin and Eosin (H&E) staining was used to study histopathological changes in morphology and TUNEL assay to evaluate levels of apoptotic cell death. Male and female rabbits showed no significant differences in corneal opacity (Fantes score) or intraocular pressure (IOP) values (9.5 ± 0.5 mm Hg) in live animals. Likewise, no statistically significant sex-based differences in the mRNA levels of α-SMA (male = 5.95 ± 0.21 fold vs. female = 5.32 ± 0.043), FN (male = 3.02 ± 0.24 fold vs. female = 3.23 ± 0.27), Col-I (male = 3.12 ± 0.37 fold vs. female = 3.31 ± 0.24), TGFβ1 (male = 1.65 ± 0.06 fold vs. female = 1.59 ± 0.053); and protein levels of α-SMA (male = 74.16 ± 4.6 vs. female = 71.58 ± 7.1), FN (male = 60.11 ± 4.6 vs. female = 57.41 ± 8.3), Col-I (male = 84.11 ± 2.8 vs. female = 84.55 ± 3.6), TGFβ1 (male = 11.61 ± 2.8 vs. female = 9.5 ± 3.04) were observed. Furthermore, H&E and TUNEL analyses found no statistically significant differences in cellular structures and apoptosis, respectively, in male vs. female corneas. Consistent with earlier reports, wounded corneas showed significantly increased levels of these parameters compared to the unwounded corneas. Our data suggest that sex is not a major biological variable during active early stages of corneal wound healing in rabbits in vivo.

Suspected Iatrogenic Seeding of Oral Melanoma Secondary to Endotracheal Intubation in a Dog

A 10 yr old castrated male pug was presented with a 3 day history of intermittent dyspnea, cough, inappetence, and inability to breathe while sleeping. He had previously received hypofractionated radiation therapy for an amelanotic oral malignant melanoma (OMM) 7 mo prior to presentation. At presentation, the dog was gasping and dyspneic. Oral examination identified the OMM on the right hard palate. Thoracic radiographs revealed an angular soft-tissue opacity within the trachea just distal to the thoracic inlet. No evidence of pulmonary metastatic disease was seen. Tracheoscopy identified a pedunculated, nonpigmented mass within the lumen of the distal trachea near the carina. Treatment options were presented to the owners and included tracheal stenting or tracheal resection and anastomosis. Because of the poor prognosis, the owners elected humane euthanasia. Postmortem examination confirmed the presence of melanoma in the distal trachea; no other sites of OMM metastasis were identified. The cause of OMM development in the distal trachea in this case is suspected to have resulted from mechanical tumor cell seeding during endotracheal tube placement for general anesthesia 7 mo prior to presentation. Despite the reported rarity of mechanical tumor seeding, this potential complication warrants consideration in dogs with OMM.

IMMERSION IN TRICAINE METHANESULFONATE (MS-222) IS NOT SUFFICIENT FOR EUTHANASIA OF SMOKEY JUNGLE FROGS (LEPTODACTYLUS PENTADACTYLUS)

Although tricaine methanesulfonate (MS-222) immersion has historically been standard of care for fish and anuran euthanasia, recent research has proven it insufficient for euthanasia of goldfish. To assess appropriateness for humane euthanasia of anurans, this study evaluated the efficacy of MS-222 in Smokey Jungle Frogs (Leptodactylus pentadactylus). Eighteen frogs (21-33 g) were exposed to one of three MS-222 concentrations via partial immersion: 2.5 g/L for 90 min (M2.5/90), 5 g/L for 60 min (M5/60), or 10 g/L for 60 min (M10/60). Physiologic parameters and times to loss of spontaneous movement, righting reflex, and noxious stimulus response were recorded. Following exposure, frogs were rinsed with dechlorinated water, and time to cessation of heart beat was recorded. Survival in M2.5/90, M5/60, and M10/60 was one of six, zero of six, and zero of six, respectively. In M2.5/90, three of six frogs had continued purposeful, spontaneous movement throughout exposure. In M5/60 and M10/60, median (range) time to initial loss of movement was 14.3 (5.5-30.0) and 7.6 (4.8-19.7) min, respectively. Twelve of 18 frogs among all groups demonstrated a median (range) of two (one to six) episodes of regained consciousness with purposeful, spontaneous movement following loss of noxious stimulus response. Median (range) time to heart beat cessation in M2.5/90, M5/60, and M10/60 was 150 (135-210), 157.5 (60-225), and 90 (75-210) min, respectively. Although death was achieved in 17 of 18 frogs, given the repeated events of regained consciousness, MS-222 immersion when used at concentrations ≤10 g/L did not result in rapid and distress-free death and is not sufficient for humane euthanasia in this species.

Abstract 296: Early Mitochondrial Gene Regulation in Pediatric Cardiac Arrest

Introduction: Cerebral mitochondrial dysfunction is thought to play a role in the post-cardiac arrest syndrome, propagating secondary morbidity and mortality after return of spontaneous circulation (ROSC). Hypothesis: Based on our previous studies showing a persistent decrease in oxidative phosphorylation (particularly Complex I) and increased mitochondrial fission in a swine model of in-hospital cardiac arrest, we hypothesized that nuclear and mitochondrial genes related to respiratory function would be downregulated and genes promoting mitochondrial fission would be upregulated four hours post-ROSC. Methods: One-month old piglets were subjected to sham anesthesia (n=5) or asphyxial cardiac arrest (n=6; 7 minutes of asphyxia followed by induction of ventricular fibrillation) and treated with 10-20 minutes of AHA guideline-based CPR followed by four hours of standardized post-arrest management and humane euthanasia. RNA was extracted from flash-frozen sections of cerebral cortex using a QIAsymphony robot and sequenced on an Illumina HiSeq. Reads were aligned to the reference (SusScrofa11.1 and NC_012095) using STAR and quantified using subreads. Normalization and differential expression analysis were performed using DESeq2 with RNA quality, intra-arrest and post-ROSC physiologic variables as covariates. All p values were adjusted for multiple comparisons (Benjamini-Hochberg) with a significance cutoff of 0.05. Results: Compared to sham, cardiac arrest animals demonstrated reduced expression of multiple components of the respiratory chain, including NDUFA5 (2.4-fold, p&lt;0.001) and NDUFC1 (2.0-fold, p=0.02), key components of Complex I. Components of Complex III (UQCRB, UQCRH) and Complex IV (COX1, COX7C, COX7A2, COX7B) were also downregulated. Dynamin-2 (DNM2), which increases mitochondrial fission, was upregulated (2.3-fold, p=0.005). There was also differential expression of inner membrane solute channel expression (SLC44A1, SLC25A48 and SLC25A16). Conclusions: Multiple components of the mitochondrial respiratory chain are downregulated 4 hours post-ROSC in the brain, including key components of Complex I with concurrent upregulation of the mitochondrial fission protein dynamin-2.

Humane euthanasia of neonates II: field study of the effectiveness of the Zephyr EXL non-penetrating captive-bolt system for euthanasia of newborn piglets

AbstractA previous study demonstrated the effectiveness of the Bock Industries Zephyr EXL non-penetrating captive bolt, using the abolition of visual-evoked potentials as a determination of brain death, in piglets in a laboratory. A second trial, reported here, involved the field-testing of this device, on-farm, in a commercial setting. Two hundred and seven piglets (mean [± SEM] dead weight: 1.86 [± 0.74] kg) requiring dispatch under the farm's protocols were euthanased with the device and demonstrated immediate loss of consciousness, subjectively assessed by behavioural signs and no recovery. Post mortem examination of the heads was undertaken confirming massive traumatic damage to the cerebrum with associated haemorrhage and bone plate shards forced down to the level of the corpus callosum in the majority of cases. A further trial of 106 piglets demonstrated that under commercial production conditions it took less than 7 s to select, place and euthanase a piglet using the device. One hundred percent of animals in the study were immediately killed. Given this complete kill rate and the sample size of the study, a statistical 95% confidence interval provides a maximum percentage of animals that would not immediately be stunned/killed, by this mechanical non-penetrating captive-bolt system, to be at most 1.2% and at least 0%. The results here, combined with the previous study, allow recommendation of the Bock Industries Zephyr EXL as being suitable as a single application euthanasia device for piglets up to 10.9 kg liveweight.

CT used in the diagnosis of a cisterna chyli obstruction

Chyloperitoneum is an uncommon condition reported in cats and dogs. It is often secondary to processes such as neoplasia and therefore is associated with a grave prognosis. Diagnosis of the...

Care of geriatric rabbits

With the continual advancement in veterinary medicine, rabbits have the care they need to live longer. While rabbits of all ages have similar needs, geriatric rabbits can have a longer, better quality of life with proper identification and management of age-related diseases. Important considerations for elevated quality of life for geriatric patients include: adjustments in husbandry and nutrition, and medical management of age-related diseases such as congestive heart failure, chronic renal insufficiency, and a wide variety of mobility issues. Becoming familiar with signs of age-related medical complications is extremely important due to a rabbit's natural instinct to hide signs of illness. Supportive care at home is key to the ongoing wellbeing of geriatric pets with health conditions. It is also important to be prepared to discuss the delicate subject of end-of-life care and euthanasia with owners of geriatric rabbits. Humane and stress-free euthanasia is important for all species, including pet rabbits.