Jaw Tone Research Articles

Evaluation of two protocols for chemical restraint in guinea pigs (Cavia porcellus).

Abstract: This study evaluated the cardiorespiratory parameters, analgesia, sedation depth and duration, and recovery quality in guinea pigs undergoing elective castration, using dexmedetomidine or xylazine combined with esketamine hydrochloride and morphine. In a crossover study, guinea pigs (Cavia porcellus) (n=8), 9 months and 650 g (p = 0,3831) received xylazine (1 mg/kg), esketamine (10 mg/kg), and morphine (0,5 mg/kg) (GXIL), or dexmedetomidine (5 mcg/kg), esketamine (10 mg/kg), and morphine (0,5 mg/kg) (GDEX) intramuscularly at a two-week interval. Cardiorespiratory parameters, including respiratory rate (RR), heart rate (HR), SpO2, and rectal temperature (RTºC), were recorded at baseline (M0) and every 5 minutes post-administration (M5 to M60). Sedation depth was assessed via ear/toe pinch response, jaw tone, righting reflex, posture, palpebral reflex and reaction to manipulation, based on the criteria established by D'OVÍDIO et al. (2017). Statistical analysis included the Shapiro-Wilk test, unpaired t-test, two-way repeated measures ANOVA, and non-parametric tests (Kruskal-Wallis, Wilcoxon, Mann-Whitney U). GXIL induced more profound sedation, with significant differences in ear/toe pinch response and jaw tone compared to GDEX. HR and RR significantly decreased in the GXIL group, with an average reduction of 13,6% in HR and 32,6% in RR. GDEX demonstrated less sedation depth and a milder decrease in RR. Both protocols were effective and safe for chemical restraint in guinea pigs, though GXIL provided deeper sedation and greater cardiorespiratory depression than GDEX. However, GDEX maintained a more stable cardiorespiratory profile, suggesting it. Nonetheless, both treatments provided minimal cardiorespiratory alterations, demonstrating their safety for use.

Comparison of Subcutaneous versus Intramuscular Dexmedetomidine–Midazolam–Ketamine–Morphine (DMKM) Mixture as Chemical Restraint for Endoscopic Sex Determination in Aldabra Giant Tortoises (Aldabrachelys gigantea)

Sex identification through coelioscopy is a minimally invasive surgical technique used to determine the sex of chelonians by directly visualizing their internal reproductive organs. An adequate anaesthesiologic plan is essential to guarantee patient immobilization and proper analgesia during the entire surgical procedure. In this study, we evaluated the effects of a combination of dexmedetomidine (0.05 mg/kg), midazolam (1 mg/kg), ketamine (8 mg/kg), and morphine (1 mg/kg) (DMKM) randomly delivered intramuscularly (IM) or subcutaneously (SC) in twenty-one Aldabra giant tortoise (Aldabrachelys gigantea) into the right antebrachium for celioscopic sex identification. Heart rate (HR), respiratory rate (RR), and body temperature (BT) were measured, along with the skeletal muscle tone of the thoracic and pelvic limbs, neck retraction reflex, palpebral reflex, and jaw tone every 15 min. The anaesthesiologic plan was considered to be adequate at the loss of the thoracic and pelvic limb retraction reflexes. After a 45 min interval, if the anaesthetic plan was deemed insufficient for the celioscopic procedure, a 5 mg/kg dose of propofol was administered intravenously into the subcarapacial venous plexus. At the end of the procedure, atipamezole (0.5 mg/kg) and flumazenil (0.05 mg/kg) were administered intramuscularly into the left antebrachium as reversal agents. Both HR and RR decreased from baseline to both 15 and 30 min. Due to the persistence of thoracic and pelvic limb retraction reflexes 45 min after DMKM administration, 6/11 (55%) cases in the SC group required the additional administration of propofol, in contrast to only 1/10 (10%) cases in the IM group (p = 0.05). The recovery times were comparable between the successfully induced animals in the IM and SC groups. In this study, the intramuscular administration of a DMKM combination quickly produced chemical restraint, suitable for celioscopic sex determination.

Field Based Assessment of Clinical Signs of Irreversible Loss of Consciousness and Death Confirmed by Brain Destruction in Juvenile American Alligators (Alligator mississippiensis) After Penetrating Captive Bolt Stunning or Electrostunning with Probe Pithing

ABSTRACT To determine the humane use of slaughter methods we examined the clinical signs of life in 61 American alligators harvested on-farm using one of three methods: (i) captive bolt and spinal cord severance; (ii) electrostunning, spinal cord severance and pithing; and (iii) spinal cord severance and pithing. Loss of consciousness and the six clinical signs of life that can be used on-farm were assessed for evidence of irreversible unconsciousness and death at Time 0, 0.5, 1, 2, 5, 10, 20, and 30 min post slaughter. The brains of alligators from each slaughter method were removed to assess brain tissue disruption. A combination of loss of blink reflex, pupillary light response, jaw tone and respiration are a reliable on-farm tool for determining death. Heartbeat and withdrawal reflex persisted. Captive bolt and electrostunning methods were effective in immediately producing loss of response consistent with irreversible unconsciousness, subsequent death and destruction of neural tissue integrity in the mid and hind brain. They are therefore humane forms of slaughter in American alligators.

Subcutaneous alfaxalone for sedation of the domestic ferret (Mustela putorius furo)

BackgroundVeterinary care of the domestic ferret often utilizes chemical restraint for venipuncture, radiographs, and ultrasonography. Common forms of chemical restraint for ferrets include inhalant anesthetics and parenteral sedatives. Disadvantages of these forms of chemical restraint include adverse patient reaction and environmental contamination for inhalant anesthetics while small muscle mass and patient reactivity are challenging for intramuscular injections. Alfaxalone is a unique neurosteroid anesthetic that can be used as an induction agent intravenously and a sedative agent intramuscularly and subcutaneously. Subcutaneous injection appears to be well tolerated in small exotic species due to the increased volume the subcutaneous space can accommodate as well as the ease of administration. MethodsA randomized, blinded, complete crossover study evaluating two doses (10 mg/kg and 12.5 mg/kg) of subcutaneous (SC) alfaxalone alone was performed in 10 clinically healthy ferrets (5 neutered males and 5 spayed females). Once alfaxalone was administered sedation scores (body posture, righting reflex, jaw tone, front limb withdrawal, and toe pinch) and vital parameters (heart rate, respiratory rate, rectal temperature, SpO2 and blood pressure) were evaluated at regular intervals. ResultsSedation characterized by the loss of righting reflex for more than ten minutes was observed in 90% of ferrets in both groups. The higher dose of alfaxalone (12.5 mg/kg) produced a statistically significant increase in the duration of sedation, as well as in the values of all sedation scores. Temperature significantly decreased over time for both groups, while SpO2 and respiratory rate did not display any significant changes. At both doses, no cardiovascular depression was noted but there were significant increases in heart rate and blood pressure parameters. ConclusionSubcutaneous alfaxalone in ferrets produces adequate sedation characterized by the loss of righting reflex and easy limb manipulation with no significant adverse effects. This type of sedation is appropriate for noninvasive procedures such as a physical exam, ultrasonography, and radiographic positioning without manual restraint. The limitations for SC alfaxalone, as a sole sedative agent, include the variable range in times to onset and variable durations of sedation.

The effect of body condition on alfaxalone induction dosage requirement in dogs.

Alfaxalone is commonly used in veterinary anesthesia for the induction of general anesthesia (GA) in dogs. However, it has been associated with dose-dependent cardiovascular depression. Therefore, the administration of liposoluble, intravenous (IV)-administered injectable induction agents, such as alfaxalone, is recommended to be based on the dog's lean body mass (LBM). To determine the influence of body condition score (BCS) on IV alfaxalone dose requirements to achieve endotracheal intubation in dogs. Prospective clinical study. A group of 34 dogs undergoing GA for diagnostic and/or surgical procedures, body weight (BW) > 4 kg, BCS > 2, age 1-14 years, American Society of Anesthesiologists (ASAs) classification I-III. Dogs were allocated to two different groups according to their BCS: non-overweight group (NOW) BCS: 3-5 and over-weight group (OW) BCS: 6-9. All dogs were premedicated IV with methadone 0.2 mg kg-1, and anesthesia was induced by a slow IV infusion of alfaxalone at 1 mg kg-1 minute-1, delivered with a syringe driver, until loss of jaw tone and no/minimal gagging reflex sufficient to allow endotracheal intubation was achieved. The total dose of alfaxalone and the occurrence of post-induction apnoea were recorded.The Shapiro-Wilk test was performed to test for normality. A Chi-square test was performed to compare the incidence of post-induction apnoea between groups, and the Mann-Whitney U test was performed to compare the induction dose of alfaxalone between groups. A p-value < 0.05 was considered statistically significant. The mean dose ± standard deviation of alfaxalone in NOW was 2.18 ± 0.59 mg kg-1, and in OW, it was 1.63 ± 0.26 mg kg-1 (p = 0.002). The sedation score did not differ between groups. Postinduction apnoea (PIA) occurred in 6 of 17 animals in NOW and 15 of 17 in OW (p = 0.002). The dose of IV alfaxalone per kg of total body mass required to achieve endotracheal intubation was lower in overweight dogs, suggesting that LBM should be considered when calculating IV anesthetic doses. The incidence of post-induction apnoea was higher in overweight/obese dogs with alfaxalone administered at a rate of 1 mg kg-1 minute-1.

Comparison of blind and endoscopic-guided orotracheal intubation on laryngeal and tracheal damage in domestic rabbits (Oryctolagus cuniculus)

ObjectiveTo compare blind and endoscopic-guided techniques for orotracheal intubation in rabbits and the number of intubation attempts with laryngeal/tracheal damage. Study designProspective, randomized experimental study. AnimalsA total of 24 healthy, intact female New Zealand White rabbits, weighing 2.2 ± 0.2 kg (mean ± standard deviation). MethodsRabbits were randomly assigned to blind (group B) or endoscopic-guided (group E) orotracheal intubation with a 2.0 mm internal diameter uncuffed tube. Intramuscular (IM) alfaxalone (7 mg kg–1), hydromorphone (0.1 mg kg–1) and dexmedetomidine (0.005 mg kg–1) were administered, and additional IM alfaxalone (3–5 mg kg–1) and dexmedetomidine (0.025 mg kg–1) were administered to rabbits with strong jaw tone. An intubation attempt was defined as the advancement of the endotracheal tube from the incisors to the laryngeal entrance. Tracheal intubation was confirmed via capnography and anesthesia was maintained with isoflurane for 2 hours. Following euthanasia, laryngeal and tracheal tissues were submitted for histopathology. Quality of anesthesia for orotracheal intubation, intubation procedure and tissue damage were numerically scored. Data were analyzed using Poisson regression, Spearman’s correlation, t test, mixed anova, Mann–Whitney U test, Friedman and Chi square tests as appropriate. ResultsMedian (range) intubation attempts were 2 (1–8) and 1 (1–3) for groups B and E, respectively. More rabbits in group E (91.6%) required additional alfaxalone and dexmedetomidine than in group B (16.7%). Median (range) cumulative histopathology scores were 6 (3–10) and 6 (2–9) for groups B and E, respectively. Scores were highest in the cranial trachea, but there was no difference between groups and no correlation between laryngeal/tracheal damage and the number of intubation attempts. Conclusions and clinical relevanceBoth orotracheal intubation techniques were associated with laryngeal/tracheal damage. Although blind orotracheal intubation was associated with a higher number of attempts, the tissue damage was similar between groups.

Partially Reversible Immobilization of Free-Ranging Huemul Deer (Hippocamelus bisulcus) with Medetomidine-Ketamine and Atipamezole.

A combination of intramuscular medetomidine and ketamine was used to immobilize 46 free-ranging huemul deer (Hippocamelus bisulcus) with a remote drug delivery system in Chilean Patagonia for tagging and biological sampling. Captures occurred in May-October of 2005-09 between fall and early spring in the southern hemisphere. An initial dose of 6.6 mg medetomidine and 185 mg ketamine was adjusted after 17 captures to 3 mg and 200 mg, respectively, in the 29 remaining deer. Mean±SD adjusted dose was 0.042±0.012 mg/kg of medetomidine and 2.929±0.427 mg/kg of ketamine. Inductions were calm and the mean±SD time to sternal recumbency was 10.3±10.1 min. Palpebral reflex and jaw tone were present during immobilization. Atipamezole at 5 mg/mg of medetomidine was administered intramuscularly for reversal after 55.3±18.8 min procedure time. Recoveries were smooth and mean±SD time to standing was 10.2±3.3. All immobilized animals were hypoxemic by pulse oximetry (blood oxygen saturation approximately 81%). Three animals that developed apnea were resuscitated through chest compression and atipamezole administration, another regurgitated during capture, and all developed tachypnea. The combination of medetomidine-ketamine and atipamezole can be used for partially reversible immobilization of huemul, but supplemental oxygen should be administered, blood oxygenation should be monitored, and equipment for intubation and manual ventilation should be available.

Evaluation of Tiletamine–Zolazepam Sedation in Central Bearded Dragons (Pogona vitticeps) Following Intramuscular and Subcutaneous Administration

The objective of this study was to evaluate the effects of tiletamine–zolazepam as a sedative drug in central bearded dragons (Pogona vitticeps) and determine if efficacy differed based on administration route. Ten healthy, adult central bearded dragons received tiletamine–zolazepam (20 mg/kg) either intramuscularly (IM) or subcutaneously (SC) in the cranial body in a randomized, blinded, complete crossover study with a minimum washout period of 2 wk between treatments. Respiratory rate, heart rate, body position, response to restraint, spontaneous movement, righting reflex, and jaw tone were evaluated. All bearded dragons received flumazenil (0.05 mg/kg, SC) in the cranial body 45 min after the initial tiletamine–zolazepam injection. Righting reflex was lost in all bearded dragons receiving tiletamine–zolazepam IM, but only half of the animals lost righting reflex after SC injection. Jaw tone was lost in 90% (9/10) of animals receiving IM injections compared to 40% (4/10) following SC injections. Recovery from sedation was similar between route of administration (IM: 69 ± 39 min, SC: 57 ± 33 min, P= 0.43). Postsedation food intake was suppressed 2 h after return of righting reflex. Based on the findings of this study, IM administration of tiletamine–zolazepam results in a deeper and more consistent plane of sedation in bearded dragons when compared to the SC route. Prolonged recoveries were noted with both routes of administration.

Neurological Examinations in Healthy Juvenile Bearded Dragons (Pogona vitticeps) and Adult Leopard Geckos (Eublepharis macularius)

A variety of neurological disorders have been reported in reptiles, but evaluation of a reptile patient with suspected neurological disease can be challenging. The feasibility of performing and interpreting neurological examinations may be affected by a number of factors, including species, body temperature, individual temperament, and stress levels. The aims of this study were to determine whether standard neurological examinations used in other companion animal species could be adapted for use in lizards to establish a reference for healthy animals. The inland bearded dragon (Pogona vitticeps) and leopard gecko (Eublepharis macularius) were selected as two of the most commonly presented pet lizard species. Thirty adult leopard geckos and 30 juvenile bearded dragons were provided by a private breeder as subjects for the study. A complete physical examination was performed on each animal, followed by a standardized neurological examination. Postural reactions, spinal reflexes, and cranial nerve testing were scored as absent, reduced, or present. Certain responses, such as the menace response and response to sound, were consistently absent in all animals, whereas parameters such as jaw tone and righting reflex were present in all animals. Some variation was also observed in response to other tests such as tactile placing and tail pinch. It is hoped that these findings can help clinicians prioritize tests that can be easily performed with minimal stress, and give consistent results in a healthy lizard.

The impact of vatinoxan on medetomidine–ketamine–midazolam immobilization in Patagonian maras (Dolichotis patagonum)

ObjectiveTo compare cardiovascular and ventilatory effects, immobilization quality and effects on tissue perfusion of a medetomidine–ketamine–midazolam combination with or without vatinoxan (MK-467), a peripherally acting α2-adrenoceptor antagonist. Study designRandomized, blinded, crossover study. AnimalsA group of nine healthy Patagonian maras (Dolichotis patagonum). MethodsMaras were immobilized twice with: 1) medetomidine hydrochloride (0.1 mg kg–1) + ketamine (5 mg kg–1) + midazolam (0.1 mg kg–1) (MKM) + saline or 2) MKM + vatinoxan hydrochloride (0.8 mg kg–1), administered intramuscularly. Drugs were mixed in the same syringe. At 20, 30 and 40 minutes after injection, invasive blood pressure, heart rate, respiration rate, end-tidal CO2, haemoglobin oxygen saturation, and muscle oxygenation were measured, arteriovenous oxygen content difference was calculated. Muscle tone, jaw tone, spontaneous blinking and palpebral reflex were evaluated. Times to initial effect, recumbency, initial arousal and control of the head were recorded. Paired t test, Wilcoxon matched-pairs signed rank test and analysis of variance were used to compare protocols; (p < 0.05). ResultsVatinoxan significantly reduced systolic (p = 0.0002), mean (MAP; p < 0.0001) and diastolic (p < 0.0001) arterial blood pressures between 20 and 40 minutes. MAPs at 30 minutes (mean ± standard deviation) with MKM and MKM + vatinoxan were 105 ± 12 and 71 ± 14 mmHg, respectively. Without vatinoxan, four animals were hypertensive (MAP > 120 mmHg), whereas with vatinoxan, four animals were hypotensive (MAP < 60 mmHg). Muscle and jaw tone were significantly more frequently present with MKM (both p = 0.039). Other measurements did not significantly differ between protocols. Conclusions and clinical relevanceIn Patagonian maras, vatinoxan attenuated the increase in blood pressure induced by medetomidine. Muscle and jaw tone were more frequently present with MKM, indicating that quality of immobilization with vatinoxan was more profound.

Subcutaneous tiletamine-zolazepam immobilization and effect of flumazenil reversal in African pygmy hedgehogs (Atelerix albiventris)

African pygmy hedgehogs ( Atelerix albiventris ) are popular zoological companion animals that routinely require chemical immobilization for veterinary care. The objective of this randomized, blinded, cross-over study was to evaluate the efficacy of low and high dosages of subcutaneous (SC) tiletamine-zolazepam for sedation and the efficacy of flumazenil for recovery in African pygmy hedgehogs. Twelve adult hedgehogs (7 males, 5 females) were administered tiletamine-zolazepam at 10 mg/kg (T10) or 30 mg/kg (T30) SC. Physiologic variables, reflexes and behaviors were monitored to evaluate quality of immobilization. Forty-five minutes after tiletamine-zolazepam injection, hedgehogs were administered flumazenil or an equivalent volume of saline SC. Baseline daily food intake was measured and then recorded daily for 6 days following sedation trials. Median (interquartile range [IQR]) time to onset of first effects for T10 and T30 was 2.9 minutes (2.5–5.3 minutes) and 2 minutes (1.4–2.9 minutes), respectively. Eighty-three percent of T10 and 100% of T30 hedgehogs lost righting reflex. The median (IQR) duration righting reflex was lost for T10 was 32.5 minutes (23.8–37.5 minutes) and it was lost for 47.5 minutes (36.25–63.75 minutes) for T30. Jaw tone was reduced in the majority of animals for both dosages but never lost. Heart and respiratory rate for both treatments remained within normal limits. Hedgehogs became rapidly hypothermic after induction. Flumazenil administration did not have a statistically significant effect on recovery time, but mean recovery times were 18 minutes faster for T10 hedgehogs administered flumazenil. There were no statistically significant differences in food intake within or between dosages of tiletamine-zolazepam at any time point for hedgehogs administered saline or flumazenil; however, mean food intake over the 6 days following T10 administration was 16 g/kg more for hedgehogs administered flumazenil. SC tiletamine-zolazepam at 10 and 30 mg/kg produces dose-dependent heavy sedation to light anesthesia in hedgehogs. Subjectively, while both dosages provided a sufficient depth of immobilization to permit a physical examination and noninvasive procedures like blood collection or diagnostic imaging, some jaw tone was maintained precluding endotracheal intubation. T30 provided a deeper level of immobilization than T10 but longer recovery times. Flumazenil administration did not have a statistically significant effect on recovery but recovery times were noticeably faster following SC flumazenil in hedgehogs sedated with T10. For hedgehogs immobilized with T10, mean food intake was greater when flumazenil was administered. Tiletamine-zolazepam provides an injectable option for immobilization of hedgehogs.

Effectiveness of the anaesthetic combination of tiletamine, zolazepam, ketamine and xylazine for the sterilisation of street dogs in field clinics

15 dogs presented to a sterilisation clinic in March 2017 for ovariohysterectomy or castration surgeries. All patients were initially injected with an anaesthetic combination of Telazol (tiletamine/zolazepam), ketamine and xylazine...

Anesthetic effects of dexmedetomidine-ketamine-midazolam administered intramuscularly in five-striped palm squirrels (Funambulus pennantii)

To evaluate efficacy and safety of anesthesia with dexmedetomidine-ketamine-midazolam (DKM) in five-striped palm squirrels (Funambulus pennantii). 8 male squirrels. Squirrels were anesthetized with DKM (dexmedetomidine, 0.1 mg/kg; ketamine hydrochloride, 30 mg/kg; and midazolam, 0.75 mg/kg) administered IM. Atipamezole (0.15 mg/kg) and flumazenil (0.1 mg/kg) were administered IM 40 minutes after induction of anesthesia. Vital signs and responses were recorded every 5 minutes during anesthesia. Anesthetic induction and recovery from anesthesia were rapid and without complications in all squirrels. Median anesthetic induction time was 67.5 seconds (interquartile [25th to 75th percentile] range, 5.5 seconds), and mean ± SD recovery time after drug reversal was 147 ± 79 seconds. Heart rate, respiratory rate, and rectal temperature significantly decreased during the anesthetic period. All squirrels became hypothermic by 40 minutes after induction. The righting reflex was absent during the 40-minute anesthetic period in all squirrels, with variable responses for the palpebral reflex, jaw tone, forelimb withdrawal reflex, and hind limb withdrawal reflex. Only 2 of 8 squirrels had loss of the limb withdrawal reflex in both the forelimbs and hind limbs from anesthetic induction to 25 minutes after induction. DKM appeared to provide safe and effective anesthesia in five-striped palm squirrels, but oxygen and thermal support were indicated. At the doses administered, deep surgical anesthesia was not consistently achieved, and anesthetic depth of individual squirrels must be determined before surgical procedures are performed in palm squirrels anesthetized with this drug combination.

Evaluation of the sedative and physiological effects of intramuscular lidocaine in bearded dragons (Pogona vitticeps) sedated with alfaxalone

ObjectiveTo evaluate if intramuscular (IM) lidocaine potentiates the sedative effects of alfaxalone and results in cardiopulmonary changes in sedated bearded dragons. Study designProspective experimental crossover study. AnimalsA group of eight adult bearded dragons (Pogona vitticeps) weighing 334 ± 46 g. MethodsAnimals were administered alfaxalone (10 mg kg−1 subcutaneously) and 15 minutes later either lidocaine 2% (4 mg kg−1) or 0.9% sodium chloride (0.2 mL kg−1) was administered IM in the thoracic limb. The treatments were randomized and separated by 7 days. Sedation was scored based on body position, eye closure, jaw tone, swallowing, pick up response, righting reflex and pelvic limb withdrawal reflex. Heart rate (HR) and respiratory rate (fR) were recorded every 5 minutes until recovery from sedation. ResultsLidocaine had no significant effect on duration or depth of alfaxalone sedation. HR increased significantly for <10 minutes following lidocaine administration by a median (interquartile range) of 33% (28–37%; p = 0.024). No clinically significant effects on fR occurred following lidocaine injection. Conclusions and clinical relevanceAdministration of lidocaine 2% (4 mg kg−1) IM did not potentiate alfaxalone sedation but resulted in a transient clinically relevant increase in HR.

Anatomical Pathology, Behavioral, and Physiological Responses Induced by Application of Non-penetrating Captive Bolt Devices in Layer Chickens.

We evaluated three models of non-penetrating captive bolt devices, Zephyr-E, Zephyr- EXL, and Turkey euthanasia device (TED) for time to loss of sensibility and degree of brain damage during euthanasia in four age groups of male and female layer chickens (10–11, 20–21, 30–35, 60–70 weeks respectively). Latencies to onset of insensibility and cardiac arrest were assessed to detect whether killing birds via these devices was humane and effective. Both gross and microscopic pathology evaluations were conducted to score skull and brain trauma post mortem. All three NPCB devices induced loss of breathing, pupillary reflex and nictitating membrane reflex within 5 s after application in most chickens. Latencies to loss of jaw tone and neck muscle tone were longer in 60–70 weeks old roosters (p < 0.05). Younger birds (10–21 week-old) demonstrated the longest time (p < 0.0001) to onset of tonic convulsions, time at last movement, cloacal relaxation and cessation of heart beat. A positive correlation (p < 0.0001) was found for all three devices between time of cardiac arrest and times to onset of tonic convulsions, last movement, and cloacal relaxation. More than 80% of birds had skin lacerations with external bleeding following application of all 3 devices. Device type did not affect the incidence of skull fractures but higher skull fracture scores were noted in 10–11 week-old birds compared to other ages. Regardless of device type and age, microscopic SDH was most apparent in the brain and proximal spinal cord of all birds. In summary, all three devices caused significant trauma to the midbrain and spinal cord. Results demonstrated that all three devices induce rapid insensibility after application and can be used as a single-step method that results in a humane death in all age groups of layer chickens.

Effects of Ketamine and Xylazine-Ketamine Combination in Clinical and Haemato-biochemical Parameters in Captive Rhesus Monkey (Macaca mulatta)

This study was carried to compare the effects of ketamine and xylazine-ketamine combination on clinical and haematobiochemical parameters in captive rhesus monkey. The animals were divided into two groups; one ketamine (K) group and other xylazine-ketamine (XK) group. In ketamine group (n=6) atropine sulphate and ketamine was used intramuscularly at the rate of 0.04 mg/kg body weight and 10 mg/ kg body weight respectively. In xylazine-ketamine group (n=3) xylazine and ketamine was used intramuscularly at the rate of 1 mg/kg body weight and 5 mg/kg body weight respectively. Blood samples were collected immediately after induction and 30 min after induction in both groups. Effects of anaesthetics on haematological and biochemical parameters such as TEC, TLC, Hb, PCV, DLC, serum cholesterol, serum triglyceride, HDL and LDL and clinical parameters such as rectal temperature, heart rate, respiration rate, muscle relaxation, jaw tone, pedal reflex, palpebral reflex and position of eye ball were studied. Rectal temperature was significantly lower (P&lt;0.01) in group XK than in group K. Heart rate was significantly higher (P&lt;0.01) in group K than in group XK. Respiratory rate was lower in group K than in group XK but it was nonsignificant (P&gt;0.05). Hb and PCV level was significantly lower (P&lt;0.05) in group XK than group K. TEC and TLC was higher in group K than in group XK but it was nonsignificant (P&gt;0.05). Neutrophil and Eosinophil was higher in group XK than in group K but it was nonsignificant (P&gt;0.05). Lymphocyte was lower in group XK than in group K but it was nonsignificant (P&gt;0.05). Monocyte was significantly lower (P&lt;0.05) in group XK than in group K. Serum cholesterol was higher in group XK than in group K but it was nonsignificant (P&gt;0.05). Serum triglyceride and LDL was significantly higher (P&lt;0.05) in group XK than in group K. HDL was lower in group XK than in group K but it was nonsignificant (P&gt;0.05). Smooth induction was found in group XK and duration of anaesthesia was longer in group XK whereas smooth recovery was found in group K but duration of anaesthesia was shorter. Muscle relaxation was excellent in group XK in comparison to group K. It can be suggested from the results of this study that for shorter duration of anaesthesia only ketamine can be used but for longer duration, xylazine-ketamine combination will be appropriate.

Use of Alfaxalone or Midazolam–Dexmedetomidine–Ketamine for Implantation of Radiotransmitters in Bullsnakes (Pituophis catenifer sayi)

Abstract The objective of this study was to compare the physiologic and anesthetic effects, and differences, between two intramuscular drug protocols in adult bullsnakes (Pituophis catenifer sayi); the bullsnakes were being anesthetized for a radiotelemetry study. Free-ranging bullsnakes were injected IM with 10 mg/kg butorphanol, followed by either 20 mg/kg alfaxalone or a combination of 0.5 mg/kg midazolam, 0.05 mg/kg dexmedetomidine, and 5 mg/kg ketamine (MDK). After administration, muscle tone, response to stimuli, and jaw tone were evaluated before endotracheal intubation and surgical stimulation to implant coelomic transmitters. If a bullsnake responded to stimulation induced by surgical preparation, or noxious stimuli induced by the surgical procedure, isoflurane was administered to maintain a surgical plane of anesthesia. Heart rate, sedation depth, esophageal temperature, end-tidal CO2, respirations, time to spontaneous ventilation, extubation, return of righting reflex, and return of spontaneous...

Assessing a Method of Mechanical Cervical Dislocation as a Humane Option for On-Farm Killing Using Anesthetized Poults and Young Turkeys.

Our objective was to determine the efficacy of manual cervical dislocation vs. a mechanical cervical dislocation device for on-farm killing of poults and young turkeys. Forty-two 1- and 3-week old turkeys were randomly assigned to one of three experimental groups: awake manual cervical dislocation (CD), anesthetized manual cervical dislocation (aCD), or anesthetized mechanical cervical dislocation (MCD). Anesthetized birds received an intramuscular dose of 0.3 mg/kg medetomidine and 30 mg/kg of ketamine to achieve a light plane of anesthesia. A comparison of CD vs. aCD responses indicated that the anesthetic plane did not affect jaw tone or pupillary light reflex, indicators of loss of sensibility and brain death, respectively. MCD was unsuccessful for killing 1-week old poults as indicated by the ongoing presence of the pupillary eye reflex as well as failure to achieve cardiac arrest within 5 min in 5 of 5 birds. Radiographs also indicated no vertebral dislocation or fracture. Pupillary light reflex was present in 98% and jaw tone was present in 73% of turkeys, respectively, for all groups combined, but retention of the pupillary light reflex (P < 0.001) and jaw tone (P = 0.001) was longer for birds killed by MCD. Time to last movement (P = 0.797) and cardiac arrest (P = 0.057) did not differ between method. Survey radiographs demonstrated an effect of method for the average displacement distance at the site of vertebral dislocation, with a greater distance observed in birds killed by CD compared to MCD (P = 0.003). A method by age interaction was observed between CD and MCD for the number of birds with fractures; more vertebral fractures were observed in 3-week old turkeys killed with MCD compared to CD (P = 0.047). Upon gross examination, the majority of birds killed by either method had minimal to no hemorrhage within the brain and spinal cord. However, turkeys killed using CD had more microscopic subdural brain hemorrhage (P = 0.020). Ante-mortem and post-mortem measures suggest that neither manual CD nor the MCD tool used in this study caused immediate insensibility, but CD resulted in a shorter latency to brain death and fewer fractures compared to MCD.

Comparison of the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization.

The aim of this study was to compare the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization. The dogs were randomly assigned to two different groups: group 1 received a lower dose of medetomidine (0.014 mg/kg) and butorphanol (0.14 mg/kg) and group 2 received a higher dose of medetomidine (0.024 mg/kg) and butorphanol (0.24 mg/kg). Anesthesia was induced with intravenous propofol and maintained with sevoflurane 2% in pure oxygen. Heart rate, SpO2, respiratory rate, EtCO2, esophageal temperature, systolic and diastolic arterial blood pressures, capillary refill time, reflexes (palpebral, pedal), jaw tone, and eye position (straight, down) were assessed. Anesthesia was monitored continuously by an anesthesiologist, and variables were recorded every 5 min. During general anesthesia, the median sevoflurane (SVO) concentrations and the median HR were significantly lower in group 2 than group 1 (p<0.05). The median HR was 96.3 (85.8-100.8) in group 1, whereas in group 2 it was 77.0 (67.5-84.6) (p<0.05). It might be concluded that the higher dose of medetomidine and butorphanol allows the use of a lower sevoflurane concentration during routine surgical treatments and ensures stable work of the cardiovascular and respiratory systems.

Comparative study of midazolam-propofol and metamizole-propofol clinical effects in domestic pigeons

This study was conducted to determine the quality of anesthesia by evaluating the clinical effects of midazolam-propofol and metamizole-propofol on domestic pigeons. The aim of the study was to choose an appropriate injectable anesthetic protocol by utilizing midazolam and metamizole as pre-anesthetic drugs in order to reduce the dose of propofol and decrease side effects. Eighteen male pigeons weighing 304.2±32.3g (mean±SD) were randomly allocated to three groups of six pigeons each. Midazolam (6 mg/kg/IM) and metamizole (500 mg/kg/IM) were used five minutes prior to administration of propofol (8 mg/kg/IV) in groups I and II, respectively, while the birds in group III (control group) received metamizole (500 mg/kg/IM). Five minutes after the last injection, clinical parameters of various systems were evaluated. Nervous system parameters declined in groups I and II, while reflexes could still be elicited in group III (P&amp;lt;0.05). There were no significant changes in the heart rate, dysrhythmia, or gastrointestinal parameters in the three groups (P&amp;gt;0.05). The birds in group II showed reduced jaw and limb muscle tone (P&amp;lt;0.05). Corneal and palpebral reflexes were absent in groups I and II (P&amp;lt;0.05). Both respiratory depth and pattern were irregular in group I, while all the parameters were normal in group II (P&amp;lt;0.05). The respiratory rate decreased in all groups after injection, although this reduction was significant only in group I (P&amp;lt;0.05). In conclusion, the combination of metamizole-propofol is safer and more compatible with the physiology of pigeons and can be used for short operations, especially when inhalation agents are contraindicated..