Anesthesia techniques used for field castration of 10 intractable horses.

Dealing with an intractable horse is a reality for nearly every equine or mixed animal veterinarian. Establishing an adequate level of sedation prior to induction of anesthesia for various clinical procedures involves little margin for error regarding the safety of the veterinarian, handler, and patient. This is further compounded by the extreme difficulty of gaining venous access required to obtain rapid and reliable results. This case series describes a technique of intramuscular sedation used for field castration of 10 captive, formerly wild horses, which may be useful for various other types of intractable horses. Key clinical message: An alternative method to sedate intractable horses for induction of anesthesia is outlined. The techniques described are accessible for most veterinary practitioners, providing small-volume, fast, and reliable intramuscular sedation.

Techniques d'anesthésie utilisées pour la castration sur le terrain de 10 chevaux réfractaires. Faire face à un cheval réfractaire est une réalité pour presque tous les vétérinaires équins ou mixtes. L'établissement d'un niveau adéquat de sédation avant l'induction de l'anesthésie pour diverses procédures cliniques implique peu de marge d'erreur en ce qui concerne la sécurité du vétérinaire, du manipulateur et du patient. Ceci est encore aggravé par l'extrême difficulté d'obtenir l'accès veineux nécessaire pour obtenir des résultats rapides et fiables. Cette série de cas décrit une technique de sédation intramusculaire utilisée pour la castration au champ de 10 chevaux captifs, autrefois sauvages, qui peut être utile pour divers autres types de chevaux réfractaires.Message clinique clé :Une méthode alternative pour calmer les chevaux réfractaires pour l'induction de l'anesthésie est décrite. Les techniques décrites sont accessibles à la plupart des vétérinaires praticiens, fournissant une sédation intramusculaire de petit volume, rapide et fiable.(Traduit par Dr Serge Messier).

An investigation of the effects of intratesticular alfaxalone and lidocaine during castration in piglets.

OBJECTIVE: To determine whether intratesticular injection of an alfaxalone-lidocaine combination can induce anesthesia and provide a rapid recovery in piglets undergoing surgical castration. STUDY DESIGN: Randomized experimental study. ANIMALS: A group of 30 male piglets, aged 2-10 days, weighing 1.3-4.6 kg. METHODS: Animals were randomly divided into three equal groups for intratesticular administration of alfaxalone + lidocaine: high dose (group HD; 8 mg kg-1 + 2.5 mg kg-1), medium dose (group MD; 6 mg kg-1 + 2 mg kg-1) and low dose (group LD; 4 mg kg-1 + 1.5 mg kg-1). Induction and recovery times, movement and vocalization were recorded. Pulse rate (PR), oxygen saturation, respiratory rate (fR), rectal temperature, blood pressure and end-tidal carbon dioxide were recorded until recovery. RESULTS: Induction time did not differ significantly among groups (p = 0.19); mean time of 2.2, 3.3 and 3.7 minutes for HD, MD and LD, respectively. Recovery time to sternal recumbency was significantly faster in LD compared with HD and MD (p = 0.005). Time to standing was mean 34.1, 31.6 and 29.6 minutes for HD, MD and LD, respectively (p = 0.58). Incidences of movement and vocalization during the castration procedure were decreased in HD and MD compared with LD, but were not statistically different. There were no differences in the physiologic data among the groups except for PR, which decreased in all three groups (p < 0.05), and fR, which increased in MD and LD (p < 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: The alfaxalone-lidocaine combinations investigated in this study induced deep sedation in all piglets. Physiologic data remained within clinically acceptable ranges, suggesting that this drug combination by intratesticular injection prior to castration in neonatal piglets is well tolerated. The authors recommend the alfaxalone (6 mg kg-1) + lidocaine (2 mg kg-1) dose.

Comparison of tranexamic acid plasma concentrations when administered via intraosseous and intravenous routes.

INTRODUCTION: There is a lack of information regarding intraosseous (IO) administration of tranexamic acid (TXA). Our hypothesis was that a single bolus IO injection of TXA will have a similar pharmacokinetic profile to TXA administered at the same dose IV. METHODS: Sixteen male Landrace cross swine (mean body weight 27.6±2.6kg) were divided into an IV group (n=8) and an IO group (n=8). Each animal received 30mg/kg TXA via an IV or IO catheter, respectively. Jugular blood samples were collected for pharmacokinetic analysis over a 3h period. The maximum TXA plasma concentration (Cmax) and corresponding time as well as distribution half-life, elimination half-life, area under the curve, plasma clearance and volume of distribution were calculated. One- and two-way analysis of variance for repeated measures (time, group) with Tukey's and Bonferonni post hoc tests were used to compare TXA plasma concentrations within and between groups, respectively. RESULTS: Plasma concentrations of TXA were significantly higher (p<0.0001) in the IV group during the TXA infusion. Cmax occurred at 4min after initiation of the bolus in the IV group (9.36±3.20ng/µl) and at 5min after initiation of the bolus in the IO group (4.46±0.49ng/µl). Plasma concentrations were very similar from the completion of injection onwards. There were no significant differences between the two administration routes for any other pharmacokinetic variables measured. CONCLUSION: The results of this study support pharmacokinetic bioequivalence of IO and IV administration of TXA.

Evaluation of a portable oxygen concentrator to provide fresh gas flow to dogs undergoing anesthesia.

This study evaluated the ability of a portable oxygen concentrator (POC) to provide fresh gas to an anesthetic machine via an Ayre's T-piece or a Bain circuit. Fraction of inspired oxygen (FiO2) was compared at flows of 0.5 to 3.0 L/min. Measured FiO2 was 96% at flow rates ≥ 1 L/min. Mean battery life at 1.0, 2.0, and 3.0 L/min was 4.21 ± 0.45, 2.62 ± 0.37 and 1.5 ± 0.07 hours, respectively. The POC proved to be useful and effective during 2 power outages. The POC was sufficient to prevent rebreathing in 70% of dogs using a T-piece circuit and 20% of dogs with a Bain circuit. A significant negative correlation between inspired CO2 and O2 flow rates was noted. A significant positive correlation between inspired CO2 and ETCO2 was documented. The occurrence of hypercarbia was associated with low O2 flow. Battery back-up was essential during power outages. The POC can be effectively used for delivery of anesthesia.

Évaluation d'un concentrateur d'oxygène portable pour fournir une circulation de gaz frais aux chiens subissant une anesthésie. Cette étude a évalué la capacité d'un concentrateur d'oxygène portable (COP) à fournir du gaz frais à l'aide d'une pièce en T d'Ayre ou d'un circuit de Bain. La fraction d'oxygène inspiré (FiO2) a été comparée à des débits de 0,5 à 3,0 L/min. La FiO2 mesurée était de 96 % à des taux de débit de ≥ 1 L/min. La durée de vie moyenne de la batterie à 1,0, à 2,0 et à 3,0 L/min était de 4,21 ± 0,45, de 2,62 ± 0,37 et 1,5 ± 0,07 heures, respectivement. Le COP s'est avéré utile et efficace durant deux pannes d'électricité. Le COP a été suffisant pour prévenir la réinspiration chez 70 % des chiens en utilisant un circuit de pièce en T et un circuit de Bain chez 20 % des chiens. Une corrélation négative importante entre le CO2 inspiré et les taux de débit d'O2 a été observée. Une corrélation positive importante entre le CO2 inspiré et l' ETCO2 a été documentée. L'occurrence de l'hypercarbie était associée à un faible débit d'O2. Une batterie de secours était essentielle durant les pannes d'électricité. Le COP peut être efficacement utilisé pour fournir de l'anesthésie.(Traduit par Isabelle Vallières).

Onset, duration and efficacy of four methods of local anesthesia of the horn bud in calves.

OBJECTIVE: To determine the onset, duration and efficacy of four local anesthetic methods for the horn bud in calves. STUDY DESIGN: Crossover study. ANIMALS: Eight, 2 month-old Holstein Friesian bull calves. METHODS: Calves were subjected to one of the four following treatments: 1) cornual nerve block (C), 2) ring block (R), 3) cornual nerve block using a percutaneous jet delivery technique (JET) all using 2% lidocaine with epinephrine (0.01 mg mL(-1)), and 4) topical eutectic mixture of local anesthetics (EMLA) cream. A peripheral nerve stimulator was used to assess cutaneous sensation over the horn bud using a graded response. Onset, duration and efficacy of anesthesia were determined. RESULTS: The efficacy of the blocks was as follows: C 87.5%, R 100%, JET 37.5%, EMLA 0%. The median onset time and duration of anesthesia for C and R were: 2 (range 0.5-5) and 304 (range 107-512), and 3.25 (range 1-9) and 147 (range 62-299) minutes, respectively. Three of eight JET injections had a median onset and duration of 8 (range 0.5-9) and 132 (range 101-155) minutes, respectively. The duration of the C block was significantly longer than the R block (p = 0.047). CONCLUSIONS AND CLINICAL RELEVANCE: The relatively rapid onset and long duration of anesthesia with C or R blocks using 2% lidocaine with epinephrine validates their practical use in dehorning calves while jet injection and EMLA cream provided insufficient analgesia to be clinically useful. The efficacy of the C block requires further study.

Open-drop anesthesia for small laboratory animals.

This study examined the effect of temperature on volatile concentrations of 2 inhalant anesthetics, isoflurane (ISO) and sevoflurane (SEVO), delivered via open-drop technique, as well as the characteristics of induction and recovery using the open-drop method in mice. Testing revealed that temperature had no effect on the volatile concentration of either ISO or SEVO. However, it was determined that open-drop delivery of ISO or SEVO is a viable means of anesthetizing mice under certain conditions. The volatile concentration required to induce anesthesia in mice following the application of 0.5 mL of anesthetic in an induction chamber of 725 mL volume at 87.6 kPa and 20°C was measured with a precision gas analyzer. For ISO, anesthesia was induced at concentrations of 6.80 ± 0.57% [mean ± standard deviation (s)] after 35.70 ± 6.95 s (n = 10), while SEVO induction took significantly longer (45.50 ± 9.96 s) and required higher volatile concentrations [7.41 ± 0.57% (n = 10)]. The animals recovered rapidly from both ISO and SEVO-based induction.

Intranasal naltrexone and atipamezole for reversal of white-tailed deer immobilized with carfentanil and medetomidine.

Carfentanil and medetomidine were used to immobilize 8 captive female white-tailed deer (Odocoileus virginianus) using mean dosages [+/- standard deviation (s)] of 14.2 +/- 1.11 microg/kg carfentanil and 17.8 +/- 2.03 microg/kg of medetomidine. Deer were reversed by intranasally or intramuscularly administered naltrexone and atipamezole. Dosages of carfentanil and medetomidine proved reliable for immobilization of most, but not all deer, with a mean induction time of 13.3 +/- 3.13 min. Effective and reliable immobilization will require higher dosages of carfentanil and possibly medetomidine than were used in this study. No significant differences in recovery times were observed for deer given reversal agents intranasally (9.45 +/- 5.37 min) versus intramuscularly (7.60 +/- 4.42 min). Naltrexone and atipamezole can be administered intranasally at 1.5 mg/kg and 0.1 mg/kg, respectively to safely and quickly reverse the effects of carfentanil and medetomidine in immobilized white-tailed deer. This route could potentially be useful for other reversal agents.

Physiologic effects of nasal oxygen or medical air administered prior to and during carfentanil-xylazine anesthesia in North American elk (Cervus canadensis manitobensis).

This study compared the physiologic effects of carfentanil-xylazine anesthesia in elk administered nasal oxygen or medical air. Eight female 5 +/- 2-yr-old (mean +/- SD) captive elk (Cervus canadensis manitobensis) weighing 245 +/- 20 kg and habituated to chute restraint were studied in a randomized crossover. Nasal insufflation of oxygen or medical air (10 L/min) was provided prior to and throughout anesthesia. Baseline data were collected before i.m. injection of carfentanil (10 microg/kg) and xylazine (0.2 mg/kg). Arterial blood gases (PaO2 and PaCO2), arterial blood pressure, heart and respiratory rate, and observations of muscle rigidity and movement were collected every 3 min for 30 min. Drugs were antagonized at 30 min with i.m. naltrexone (1 mg/kg) and tolazoline (2 mg/kg). Induction and recovery were significantly faster (mean +/- SD) in elk receiving oxygen (208 +/- 39 and 333 +/- 63 sec, respectively), vs. medical air (306 +/- 84 and 532 +/- 201 sec). Elk receiving oxygen had a significantly higher PaO2 and PaCO2, and significantly lower pH and heart rate. Minimum PaO2 was 75 +/- 30 mm Hg (oxygen), and 28 +/- 6 mm Hg (air). Maximum PaCO2 was 89 +/- 5 mm Hg (oxygen), and 64 +/- 4 mm Hg (air). Frequency of rigidity and movement decreased when PaO2 > or = 70 mm Hg. Animals breathing air demonstrated slower inductions and recoveries, severe hypoxemia, and increased rigidity and movement. Oxygen administration reduced hypoxemia and improved anesthesia quality, but caused prolonged periods of apnea, and moderate to severe hypercarbia and respiratory acidosis.

Clinical impacts of administering a nonsteroidal anti-inflammatory drug to beef calves after assisted calving on pain and inflammation, passive immunity, health, and growth.

Assisted calves are often born weak, injured, or oxygen deprived and have a higher risk of morbidity and mortality. The objective was to investigate the impact of using pain mitigation at birth in assisted beef calves on physiological indicators of pain and inflammation, passive immunity, health, and growth. Thirty-three primiparous cows and their calves requiring assistance at birth on two ranches located in southern Alberta were enrolled. Data collected at birth include date and time of calving, calf sex, meconium staining, presentation of calf, and calving difficulty (easy assist: one person manually delivered the calf; difficult assist: delivery by two or more people, or mechanical assistance). Within 10 min of birth, calves were stratified by calving difficulty, randomized to a medication group, and received a subcutaneous dose of meloxicam (0.5 mg/kg BW) or an equivalent volume of placebo. Cow-calf pairs were then placed in individual box stalls for observation and sampling. At birth, 1, 4, and 24 h after birth, heart rate, respiratory rate, and rectal temperature were assessed and blood samples collected to measure indicators of pain and inflammation (cortisol, corticosterone, substance P, and haptoglobin). Serum IgG concentration and failed transfer of passive immunity (serum IgG concentration <24 g/L) were assessed in the 24-h blood samples. Preweaning treatment for disease and mortality information was collected and calves were weighed at 7 to 10 d of age and at weaning. Of the 33 calves enrolled, 17 calves received meloxicam and 16 calves received a placebo. Meloxicam-medicated calves had significantly greater ADG to 7 to 10 d of age (P = 0.05) (mean = 0.9 kg/d; SE = 0.10) compared with placebo-medicated calves (mean = 0.6 kg/d; SE = 0.12). There was no significant effect of meloxicam on physiological indicators of pain and inflammation, standing or nursing by 1 h, passive immunity, health outcomes, or ADG to weaning (P > 0.1). Although this was a small sample population, meloxicam given to assisted calves at birth improved ADG in the first week of life, which may indicate an important production management tool for improving well-being in assisted calves.

Benchmarking calving management practices on western Canada cow-calf operations.

Benchmarking current calving management practices and herd demographics in the western Canadian cow-calf production system helps to fill the gap in knowledge and understanding of how this production system works. Further investigation into the relationships between management decisions and calf health may guide the development of management practices and protocols to improve calf health, especially in compromised calves after a difficult birth. Therefore, the objectives of this cross-sectional study were to describe current calving management practices on western Canadian cow-calf ranches and to investigate the association of herd demographics with herd-level incidence of calving assistance, morbidity, mortality, and use of calving and colostrum management practices. Cow-calf producers were surveyed in January 2017 regarding herd inventory and management practices during the 2016 calving season. Ninety-seven of 110 producers enrolled in the western Canadian Cow-Calf Surveillance Network responded. Average herd-level incidence of assisted calvings was 4.9% (13.5% heifers, 3.2% cows), stillbirths was 2.1% (3.3% heifers, 1.9% cows), preweaning mortality was 4.5%, and preweaning treatment for disease was 9.4% (3.0% neonatal calf diarrhea, 3.8% bovine respiratory disease, 2.6% other diseases). Greater than 90% of producers assisted calvings and would intervene with colostrum consumption if the calf did not appear to have nursed from its dam. Late calving herds (i.e., started calving in March or later) had significantly lower average herd-level incidence of assistance, treatment for disease, and mortality (P < 0.05). In earlier calving herds (i.e., started calving in January or February) producers had shorter intervals between checking on dams for signs of calving or intervening to assist with a calving (P < 0.05). In early calving herds, producers were more likely to perform hands-on colostrum management techniques such as placing the cow and calf together or feeding stored, frozen colostrum (P < 0.05). There were no associations between herd size and herd-level incidences or management techniques (P > 0.05). This study suggests that in western Canada earlier calving herds are more intensively managed, whereas later calving herds are more extensively managed. Herd demographics may be important to consider when investigating factors associated with management strategies, health, and productivity in cow-calf herds.

Quantifying subclinical trauma associated with calving difficulty, vigour, and passive immunity in newborn beef calves.

This cross-sectional study quantifies subclinical trauma associated with calving difficulty, calf vigour, and passive immunity (PI) in newborn beef calves. The degree of calving difficulty was categorised as: unassisted, easy assist (one or two people manually pulling to deliver the calf) and difficult assist (more than two people pulling, a fetal extractor (ie, calf jack), or caesarean section). Vigour assessment occurred at 10 minutes and blood sampling at 24 hours after birth in 77 beef calves. The measured blood parameters associated with trauma were creatine kinase (CK), aspartate aminotransferase (AST), and haptoglobin. Serum IgG concentration was measured, and an IgG concentration at least 24 g/l was considered as adequate PI. Calving difficulty was associated with elevated levels of CK (P=0.002) and AST (P=0.01), weak suckle reflex (P=0.001), abnormal mucous membrane colour (P<0.0001), and decreased odds of adequate PI (P=0.004). Elevated levels of CK and AST were associated with abnormal mucous membrane colour, incomplete tongue withdrawal and weak suckle reflex at birth (P<0.001). An incomplete tongue withdrawal (P=0.005) and weak suckle reflex (P=0.02) were associated with decreased IgG concentrations. Abnormal mucous membrane colour, incomplete tongue withdrawal, and a weak suckle reflex were associated with decreased odds of having adequate PI (P<0.05). Haptoglobin was not associated with any of the parameters measured. Subclinical trauma was associated with calving difficulty, decreased vigour and decreased odds of having adequate PI. Understanding the impacts of a traumatic birth may aid the development of management strategies for compromised newborn beef calves.

Cardiopulmonary Effects of a Partial Intravenous Anesthesia Technique for Laboratory Swine.

Various anesthetic protocols are used in laboratory swine, each with specific advantages and disadvantages. Partial intravenous anesthetic techniques (PIVA) help minimize dose-dependent cardiopulmonary effects of inhalant drugs. The aim of this study was to determine the cardiopulmonary effects of a PIVA in laboratory swine. In a prospective, nonrandomized clinical study, 8 healthy juvenile Landrace-White pigs were premedicated with azaperone (0.20 ± 0.20 mg/kg IM), dexmedetomidine (0.02 ± 0.002 mg/kg IM), and alfaxalone (2.0 ± 0.20 mg/kg IM), and anesthesia was induced with intravenous alfaxalone. Anesthesia was maintained by using constant-rate infusion of dexmedetomidine (2 µg/kg/h) and alfaxalone (25 µg/kg/min) in combination with isoflurane. After the fraction of expired isoflurane was adjusted to 1.1% to 1.5%, respiratory rate, heart rate, systemic and pulmonary arterial pressure, central venous pressure, cardiac output, bispectral index, systemic vascular resistance, and arterial and mixed venous blood gases were recorded every 10 min for 60 min. Statistical analysis consisted of repeated-measures one-way ANOVA. Significant decreases occurred in heart rate, pulmonary mean arterial pressure, pulmonary diastolic pressure, partial pressure of arterial oxygen, partial pressure of venous oxygen; significant increases occurred in respiratory rate, minute volume index, diastolic arterial blood pressure, systemic vascular resistance, and arterial pH over time. We consider that the observed statistically significant cardiopulmonary changes were clinically important and that the PIVA protocol provided hemodynamic and respiratory stability for short-term anesthesia of laboratory swine.

Splenectomy Versus Sham Splenectomy in a Swine Model of Controlled Hemorrhagic Shock.

INTRODUCTION: Splenectomy is controversial in acute hemorrhagic shock models. OBJECTIVE: To compare splenectomized (SP) versus sham-splenectomized (SSP) swine during acute controlled hemorrhage. METHODS: Twenty-six male Landrace White swine (mean body weight ±â€Šstandard deviation, 33.8 ±â€Š2.9 kg) were used. Ethics approval was obtained. Landrace swine underwent splenectomy (n = 13) or sham-splenectomy (n = 13), were bled to mean arterial blood pressure (MAP) of 40 mm Hg, which was held for 60 min, given 125 mL IV RescueFlow, held for a further 60 min, given whole blood, and held for a final 60 min. Tissue oxygen saturation, thromboelastography, oncotic pressure, urine volume and specific gravity, complete blood count, serum chemistry, body temperature, hematocrit, total solids, arterial and mixed venous blood gas, bispectral index, SAP, MAP, DAP, cardiac index, total blood volume (TBV) removed and returned, rate of hemorrhage and transfusion, spleen weight, heart rate (HR), arterial pH, lactate, PaO2, PaCO2, respiratory rate, cranial mesenteric and renal artery blood flow were recorded. Groups were compared using two-way ANOVA with post hoc Bonferroni (P < 0.05) for repeated measures or t test for non-repeated measures. RESULTS: Compared with the SSP swine, SP swine had higher HR post-splenectomy for the duration of the experiment (P < 0.03), and higher hematocrits at 15 and 60 min post splenectomy (P < 0.01, P < 0.001, respectively). SSP swine had greater TBV removed during hemorrhage (P < 0.01); however, when blood loss based on splenic weight was considered, TBV removed was similar between groups. CONCLUSION: Splenectomy likely accounts for the transient increase in hematocrit and the higher HR in SP swine prior to hemorrhage, and the differences in TBV removed between the two groups during hemorrhage. With a fixed end point model using a moderate rate of acute hemorrhage and an MAP of 40 mm Hg, splenectomy is not necessary and may confound results.

Physiologic responses of grizzly bears to different methods of capture.

The physiologic effects of two methods of capture, chemical immobilization of free-ranging (FR) bears by remote injection from a helicopter and physical restraint (PR) by leg-hold snare prior to chemical immobilization, were compared in 46 grizzly bears (Ursus arctos) handled during 90 captures between 1999 and 2001. Induction dosages and times were greater for FR bears than PR bears, a finding consistent with depletion of, or decreased sensitivity to, catecholamines. Free-ranging bears also had higher rectal temperatures 15 min following immobilization and temperatures throughout handling that correlated positively with induction time. Physically restrained bears had higher white blood cell counts, with more neutrophils and fewer lymphocytes and eosinophils, than did FR bears. This white blood cell profile was consistent with a stress leukogram, possibly affected by elevated levels of serum cortisol. Serum concentrations of alanine aminotransferase, aspartate aminotransferase, and creatine kinase were higher in PR bears that suggested muscle injury. Serum concentrations of sodium and chloride also were higher in PR bears and attributed to reduced body water volume through water deprivation and increased insensible water loss. Overall, different methods of capture resulted in different patterns of physiologic disturbance. Reducing pursuit and drug induction times should help to minimize increase in body temperature and alteration of acid-base balance in bears immobilized by remote injection. Minimizing restraint time and ensuring snare-anchoring cables are short should help to minimize loss of body water and prevent serious muscle injury in bears captured by leg-hold snare.

Anesthesia of polar bears using xylazine-zolazepam-tiletamine or zolazepam-tiletamine.

Immobilization features and physiologic effects of combinations of xylazine-zolazepam-tiletamine (XZT) and zolazepam-tiletamine (ZT or Telazol) were compared in nine captive and 17 free-ranging polar bears (Ursus maritimus) between 1998 and 2001. Although induction time was similar between drugs, induction dosage and volume were less with XZT. Induction of immobilization with XZT was predictable and smooth, muscle relaxation was good, and all bears remained completely immobilized and unresponsive to stimuli throughout a 1 hr handling period. The combination XZT was safely tolerated at two to three times the recommended dosage of 5 mg/kg (i.e., xylazine at 2 mg/kg + Telazol at 3 mg/kg). Bears immobilized with XZT had slower pulse rates, higher mean arterial pressures, and lower arterial oxygen tensions than bears immobilized with ZT. Rectal temperature increased slowly over time (approximately 0.5 C per hr) following immobilization with XZT. Based on response to a painful stimulus (compression of a claw bed), XZT was a more effective analgesic than ZT. Although the immobilization effects of XZT could not be reversed with the alpha 2-antagonist drug tolazoline, they were reversed with yohimbine or atipamezole. However, the time to complete reversal of effects (i.e., standing and ambulatory) was highly variable among bears.

Intranasal administration of xylazine to reduce stress in elk captured by net gun.

Forty free-ranging elk (Cervus elaphus manitobensis) were captured by net gun in Riding Mountain National Park (Manitoba, Canada) during February 2002 and were administered either saline (control) or xylazine by the intranasal route, to evaluate the efficacy and benefit of intranasal xylazine to reduce stress. Elk that received xylazine had higher relaxation scores than control elk, and the onset of sedation occurred quickly, often <1 min. Serum concentrations of cortisol, creatine kinase, and gamma-glutamyltransferase were lower in elk that received xylazine than in control elk. At the conclusion of handling, the intravenous administration of yohimbine quickly abolished the sedative effect of xylazine, which allowed elk to be released without concern of physical injury due to ataxia. The intranasal administration of xylazine can be used to reduce stress in wild animals under situations where they are being handled while physically restrained.

Comparative analgesic and cardiopulmonary effects of bupivacaine and ropivacaine in the epidural space of the conscious dog.

OBJECTIVE: To compare the cardiopulmonary effects and sensory blockade of epidural bupivacaine and ropivacaine. STUDY DESIGN: Prospective randomized study. ANIMALS: Six young adult medium-sized crossbred dogs weighing 25.7 ± 7.1 kg. METHOD: Dogs were chronically implanted with a lumbosacral epidural catheter. Acepromazine sedated dogs received all treatments: 0.5% bupivacaine at 0.14 mL kg-1 (LB5) or 0.22 mL kg-1 (HB5); 0.5% ropivacaine at 0.14 mL kg-1 (LR5) or 0.22 mL kg-1 (HR5); 0.75% bupivacaine at 0.22 mL kg-1 (HB7.5) or 0.75% ropivacaine at 0.22 mL kg-1 (HR7.5). Loss of sensation was tested at the level of the perineum, hind toe webs, flank, and caudodorsal rib areas before injection, and post-injection (PI) up to 150 minutes PI. Systemic arterial blood pressure and heart rate were recorded before injection, and every 10 minutes PI until 150 minutes PI. Arterial blood gas analyses were performed prior to injection, and at 30, 60 and 150 minutes PI. RESULTS: No statistical differences existed between groups for the cardiopulmonary data or time to onset of block. Group HR7.5 had lower systolic (10-70 minutes PI) and diastolic (10-70 minutes PI) blood pressures and group HR5 had lower mean (10-90 minutes PI) and diastolic (10-90 minutes PI) blood pressures compared to baseline. Heart rate was lower compared to baseline in groups LR5 and HB7.5. A significant, but mild metabolic acidosis developed in groups LR5 and HB7.5 (150 minutes PI). No differences were present for the duration of block between groups, but duration of block in the dorsocaudal rib area was shorter in group HR5 compared to HR7.5. CONCLUSION: Epidural ropivacaine and bupivacaine at the doses used have mild effects on the cardiopulmonary system, and extent of block are similar. CLINICAL RELEVANCE: The 0.75% concentration of bupivacaine and ropivacaine at 0.22 mL kg-1 appeared to contribute to greater success of block (>80%) at dermatomes L5-L7.

A romifidine and morphine combination for epidural analgesia of the flank in cattle.

The objective of the study reported here was to determine the onset, duration, and degree of analgesia achieved with a combination of romifidine (50 microg/kg body weight [BW]) and morphine (0.1 mg/kg BW) administered epidurally. Ten adult Holstein Friesen cows were assigned to either a treatment group receiving the romifidine and morphine combination or a control group receiving 0.9% saline in a randomized, blinded, crossover design. Cows were assessed for degree of flank analgesia and systemic sedation at various time intervals over a period of 24 hours. The romifidine and morphine combination, compared with saline, provided significant analgesia for at least 10 minutes (P = 0.016) and up to 12 hours (P = 0.004) after epidural administration. Treated cows were sedate between 10 minutes (P = 0.016) and 6 hours (P = 0.002) after epidural administration. These results provide evidence for a potential cost-effective intra- and postoperative method of analgesia; however, the sedation seen in this study could be detrimental to patients expected return to the farm shortly after surgery. Further research into withdrawal times, systemic effects, and potential adverse effects are needed before an opiod and alpha2-adrenergic agonist combination can be used safely in a clinical setting.

Comparison of lidocaine and compression for velvet antler analgesia in wapiti.

This research compared ring block lidocaine anesthesia (L) and compression (C) for velvet antler removal in elk. Thirty-two wapiti were given 1 mg/kg body weight of zuclopenthixol acetate. The next day, they were restrained in a hydraulic chute and given either a compression device or a lidocaine ring block on the antler pedicle. Behavioral and physiological responses to treatment application and antler removal were recorded, and blood was collected for cortisol analysis. During application of L and C, increases in mean heart rate and systolic arterial blood pressure were greater in the C treatment group (P < 0.05, and P = 0.05, respectively). When antler was removed, more behavioral responses occurred in the C treatment group (P = 0.02) and its median behavior score was higher (P = 0.03). Mean heart rates increased for both treatment groups when antlers were removed (P < 0.01). It was concluded that application of C may be painful, and that C was not as effective as L for analgesia for velvet antler removal.

Comparison of arterial and venous whole blood clot initiation, formation, and strength by thromboelastography in anesthetized swine.

Thromboelastography (TEG) analysis was used to determine if differences exist between venous and arterial samples in anesthetized swine, using identical sampling techniques for each of the samples. We hypothesized that TEG parameters would not differ between native whole blood venous and arterial samples. Thirty male Landrace swines were included in the study. Both the femoral artery and vein were catheterized using standard cut-down techniques and with identically sized catheters to rule out any catheter size effects on the results. Standard TEG parameters for native whole venous and arterial blood samples (r, K, α, MA, G, and coagulation index) were measured or calculated, and t-test or Mann-Whitney rank-sum test used for comparison when appropriate. Significant differences were detected for r (venous < arterial), K (venous < arterial), α (venous > arterial), and coagulation index (venous > arterial) TEG parameters. No significant differences were measured for MA or G. These differences are important, especially when temporal changes in TEG are utilized to monitor patient stability and fluid therapy protocols using trends in coagulation properties. Taken together, these results suggest that clots are more likely to form at a faster rate in venous samples compared to arterial samples, but the overall clot strength does not differ. Therefore, if TEG analysis is being used to monitor coagulation profiles in a patient, care should be taken to use the same site and technique if results are to be used for comparative purposes.