Patterns of gastrointestinal parasite infections in bighorn sheep, Ovis canadensis, with respect to host sex and seasonality.

Males and females in sexually dimorphic species show differences in their physiology and behaviour due to differences in energetic investment into reproduction and soma. This means that the two sexes may show different patterns of parasitism at different times of the year. In this study, we evaluate the abundance of fecal eggs and larvae of 5 parasite types (Strongyles, Nematodirus spp., Marshallagia marshalli., Protostrongylus spp. lungworms, and Eimeria spp.) in relation to season and sex in Rocky Mountain bighorn sheep (Ovis canadensis). We use fecal egg counts (FEC) as a proxy for infection intensity. Parasite FECs differed between male and female bighorn sheep and varied with season. We found pronounced fluctuations in fecal egg counts of various parasite species in males and females across different seasons and reproductive stages. Strongyle counts were significantly higher during late gestation and lactation/summer, and particularly pronounced in males. Nematodirus counts were highest during late gestation in females and during the rut in males. Marshallagia counts peaked during late gestation in females and during the rut in males. Protostrongylus spp. lungworm counts were highest during late gestation in females and in males during lactation/summer and the rut. Eimeria oocyst counts varied across seasons, with higher counts in males during the rut and in females during winter and late gestation. Additionally, significant differences in Strongyle counts were observed between coursing and tending rams, with tending rams exhibiting higher counts. We discuss why the sexes might differ in FECs and suggest that differences between FECs of the parasites across seasons may be due to different life cycles and cold tolerance of the parasites themselves.

Evaluation of a noncontrolled, pre-euthanasia, intramuscular sedation drug protocol including alfaxalone 4%, medetomidine, and acepromazine for injured or ill raccoons.

Background: As a major animal control service provider in the city of Guelph and Wellington County in Ontario, the Guelph Humane Society transports and presents injured or ill raccoons requiring humane euthanasia to the Ontario Veterinary College Health Sciences Centre (OVC-HSC). Issues around handling, transportation, and delays before euthanasia have recently raised some concerns for welfare and the need for means of improving this process. Objective: Investigation of a noncontrolled sedation and analgesia protocol for injured or ill raccoons intended to improve animal welfare by allowing humane handling, transport, and euthanasia following administration by an animal protection officer (APO). Animals and procedure: Twenty-seven injured or ill raccoons requiring transport and euthanasia, as determined by the Guelph Humane Society APOs, were included in the study. Each raccoon was administered acepromazine (0.05 mg/kg), alfaxalone (4 mg/kg), and medetomidine (0.15 mg/kg), intramuscularly, before being transported to the OVC-HSC for humane euthanasia. Results: The combination of acepromazine, alfaxalone, and medetomidine was suitable for administration by APOs and provided the desired sedation depth to allow transport and humane euthanasia. Transit time was the only predictor of sedation depth upon arrival at the OVC-HSC. Two raccoons showed mild physical response to intracardiac injection for euthanasia. Numerical cutoff points of an in-hospital visual analog score of sedation of ≥ 70/100 and duration of sedation of < 62 min showed zero probability of response to euthanasia. Conclusion and clinical relevance: Administration of acepromazine, alfaxalone, and medetomidine at the stated doses provided acceptable sedation and analgesia to improve animal welfare during transport and eventual euthanasia of raccoons.

Évaluation d'un protocole médicamenteux sans groupe témoin de sédation intramusculaire, pré-euthanasie, comprenant de l'alfaxalone 4 %, de la médétomidine et de l'acépromazine pour les ratons laveurs blessés ou malades. Contexte: En tant que fournisseur majeur de services de contrôle des animaux dans la ville de Guelph et dans le comté de Wellington en Ontario, la Guelph Humane Society transporte et présente les ratons laveurs blessés ou malades nécessitant une euthanasie sans cruauté au Ontario Veterinary College Health Sciences Centre (OVC-HSC). Les problèmes liés à la manutention, au transport et aux délais avant l'euthanasie ont récemment soulevé des inquiétudes quant au bien-être et à la nécessité de trouver des moyens d'améliorer ce processus. Objectif: Enquête sur un protocole de sédation et d'analgésie sans groupe témoin pour les ratons laveurs blessés ou malades destiné à améliorer le bien-être des animaux en permettant une manipulation, un transport et une euthanasie sans cruauté après administration par un agent de protection des animaux (APO). Animaux et procédure: Vingt-sept ratons laveurs blessés ou malades nécessitant un transport et une euthanasie, tel que déterminé par les APO de la Guelph Humane Society, ont été inclus dans l'étude. Chaque raton laveur a reçu de l'acépromazine (0,05 mg/kg), de l'alfaxalone (4 mg/kg) et de la médétomidine (0,15 mg/kg), par voie intramusculaire, avant d'être transporté à l'OVC-HSC pour une euthanasie sans cruauté. Résultats: La combinaison d'acépromazine, d'alfaxalone et de médétomidine convenait à l'administration par un APO et fournissait la profondeur de sédation souhaitée pour permettre le transport et l'euthanasie sans cruauté. Le temps de transit était le seul prédicteur de la profondeur de la sédation à l'arrivée à l'OVC-HSC. Deux ratons laveurs ont montré une légère réponse physique à une injection intracardiaque pour l'euthanasie. Les seuils numériques d'un score analogique visuel de sédation à l'hôpital ≥ 70/100 et d'une durée de sédation < 62 min ont montré une probabilité nulle de réponse à l'euthanasie. Conclusion et pertinence clinique: L'administration d'acépromazine, d'alfaxalone et de médétomidine aux doses indiquées a fourni une sédation et une analgésie acceptables pour améliorer le bien-être des animaux pendant le transport et l'euthanasie éventuelle des ratons laveurs.(Traduit par Dr Serge Messier).

A PRELIMINARY STUDY TO EVALUATE THE EFFECTIVENESS OF LARYNGEAL MASK AIRWAYS IN ANESTHETIZED BIGHORN SHEEP (OVIS CANADENSIS) LAMBS.

Chemical immobilization of wildlife, required for many biological studies and management events, often induces hypoxemia and respiratory depression. Laryngeal mask airways (LMAs) have shown promise as an efficient method of airway protection during anesthesia. Nineteen wild bighorn sheep (Ovis canadensis) lambs were immobilized using an IM combination of medetomidine (0.16 ± 0.062 mg/kg), azaperone (0.20 ± 0.058 mg/kg), and alfaxalone (0.54 ± 0.21 mg/kg) via remote injection. Upon recumbency, arterial blood gas parameters, minute ventilation (VE), tidal volume (VT), and respiratory rate were measured before and after LMA placement. The VE and VT were measured via respirometer. Time to LMA placement, cuff pressure, cuff volume, and ease of placement were measured. Medetomidine was reversed with IM atipamezole at five times the medetomidine dose upon completion of procedures. Pre- and post-LMA measurements were compared using a t test or a Wilcoxon signed-rank test based on normality of the data. The LMA provided a patent airway in all lambs with a significant (P < 0.0001) increase in VE (mean [95% CI]; pre-LMA: VE = 17.3 [16.2-18.5] L/min, post-LMA: VE = 19.8 [18.6-21.0] L/min) but did not have a significant impact on partial pressure of oxygen (PaO2; pre-LMA: corrected PaO2 = 45.2 [41.2-49.2] mm Hg, post-LMA: corrected PaO2 = 47.5 [43.3-51.7] mm Hg; P = 0.19) or partial pressure of carbon dioxide (PaCO2; pre-LMA: PaCO2 = 50.4 [46.6-53.2] mm Hg, post-LMA: PaCO2 = 51.6 [48.8-55.7] mm Hg; P = 0.035) following placement. This study demonstrated that the LMA is a viable option for airway protection in wild bighorn sheep.

PHYSIOLOGICAL EFFECTS OF AZAPERONE AND MIDAZOLAM ON NETGUN-CAPTURED MULE DEER (ODOCOILEUS HEMIONUS).

Netgun capture is a commonly used capture method for mule deer (Odocoileus hemionus) in North America. Mortalities during netgun captures are generally low, and most often caused by direct trauma and occasionally fatal capture myopathy. Capture is a stressful event for a wild animal, and subclinical capture myopathy is difficult to measure. The use of tranquilizers during netgun capture is not widespread. We compared physiologic variables from 250 netgun-captured deer (57 males and 193 females) that did or did not receive midazolam and azaperone (mean, 0.14 mg/kg; SD, 0.02 mg/kg; range, 0.08-0.21 mg/kg) at time of capture and before transporting to a processing location, with the goal of evaluating whether drug administration would improve or worsen the physiologic state of the animal. Deer were captured in association with management activities between December 2018 and March 2020, with 132 deer receiving midazolam and azaperone at time of capture. Variables recorded included chase times, time from capture to arrival at the processing location, time from capture to release, serial rectal temperatures, heart rates, respiratory rates, body condition, age, sex, O2 administration, creatine kinase, aspartate aminotransferase, packed cell volume, red blood cell concentration, and hemoglobin, as well as serial venous pH, pCO2, HCO3-, and base excess. All animals were collared with GPS tracking devices and monitored after release. There was no difference in survival after capture between deer that did or did not receive midazolam and azaperone. All animals experienced severe metabolic lactic acidosis, which generally worsened with increasing chase time, highlighting the critical importance of limiting chase times during captures. Drug administration did not influence the degree of metabolic acidosis; however, it appeared to have a favorable effect on several stress-related indices, including rectal temperature, heart rate, respiratory rate, and packed cell volume.

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).

The utility of a novel formulation of alfaxalone in a remote delivery system.

OBJECTIVE: To quantify induction time, reliability, physiological effects, recovery quality and dart volume of a novel formulation of alfaxalone (40 mg mL-1) used in combination with medetomidine and azaperone for the capture and handling of wild bighorn sheep. STUDY DESIGN: Prospective clinical study. ANIMALS: A total of 23 wild bighorn sheep (Ovis canadensis) in Sheep River Provincial Park, AB, Canada. METHODS: Free-ranging bighorn sheep were immobilized using medetomidine, azaperone and alfaxalone delivered with a remote delivery system. Arterial blood was collected for measurement of blood gases, physiologic variables (temperature, heart and respiratory rates) were recorded and induction and recovery length and quality were scored. RESULTS: Data from 20 animals were included. Administered dose rates were alfaxalone (0.99 ± 0.20 mg kg-1; 40 mg mL-1), azaperone (0.2 ± 0.04 mg kg-1; 10 mg mL-1) and medetomidine (0.16 ± 0.03 mg kg-1; 30 mg mL-1). The mean drug volume injected was 1.51 mL. The median (range) induction time was 7.7 (5.8-9.7) minutes, and recovery was qualitatively smooth. CONCLUSIONS AND CLINICAL RELEVANCE: An increased concentration formulation of alfaxalone was administered in combination with medetomidine and azaperone, and resulted in appropriate anesthesia for the capture and handling of bighorn sheep. The dart volume was small, with potential for reducing capture-related morbidity.

Evaluation of intramuscular sodium nitroprusside injection to improve oxygenation in white-tailed deer (Odocoileus virginianus) anesthetized with medetomidine-alfaxalone-azaperone.

OBJECTIVE: In ungulates, α2-adrenergic agonists can decrease oxygenation possibly through alteration of pulmonary perfusion. Sodium nitroprusside can decrease pulmonary vascular resistance (PVR) and increase cardiac output (Q˙t) through vasodilation. The objective was to determine if sodium nitroprusside would improve pulmonary perfusion and attenuate the increased alveolar-arterial (a-a) gradient resulting from medetomidine-azaperone-alfaxalone (MAA) administration. STUDY DESIGN: Prospective, randomized, crossover study with a 2 week rest period. ANIMALS: A group of eight adult female captive white-tailed deer (Odocoileus virginianus). METHODS: Deer were administered MAA intramuscularly (IM), and auricular artery and pulmonary artery balloon catheters were placed. Deer spontaneously breathed air. Saline or sodium nitroprusside (0.07 mg kg-1) were administered IM 40 minutes after MAA injection. Heart rate (HR), mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), pulmonary artery occlusion pressure (PAOP), right atrial pressure (RAP), Q˙t, arterial pH, PaCO2 and PaO2 were obtained immediately before nitroprusside injection (baseline) and 5, 10 and 15 minutes afterwards. Mixed venous blood samples were obtained at baseline and at 5 minutes. Systemic vascular resistance (SVR), PVR, intrapulmonary shunt fraction (Q˙s/Q˙t), a-a gradient, oxygen delivery (D˙O2) and oxygen extraction ratio (O2ER) were calculated. Statistical analysis was performed with repeated measures analysis of variance with correction factors. A p value < 0.05 was considered significant. RESULTS: With nitroprusside, MAP, MPAP, PAOP, RAP, SVR and O2ER significantly decreased and HR, Q˙t and D˙O2 increased compared with baseline and between treatments. There was a significant decrease in PVR and a-a gradient and increase in PaO2 compared with baseline and saline treatment. Changes were not sustained. CONCLUSIONS AND CLINICAL RELEVANCE: Nitroprusside temporarily changed hemodynamic variables, increased PaO2 and decreased a-a gradient. Nitroprusside possibly led to better pulmonary perfusion of ventilated alveoli. However, IM nitroprusside at this dose is not recommended because of severe systemic hypotension and short action.

ORAL HALOPERIDOL PREMEDICATION TO REDUCE CAPTURE STRESS PRIOR TO XYLAZINE-KETAMINE ANESTHESIA IN CAPTIVE SPOTTED DEER (AXIS AXIS).

A prospective clinical trial was performed to evaluate the efficacy of haloperidol premedication prior to xylazine-ketamine anesthesia with a goal of reducing capture stress in adult male captive spotted deer (Axis axis). On the morning of the study, deer were fed a banana either containing haloperidol tablets (1 mg/kg) (haloperidol group, n = 10) or without haloperidol (placebo group, n = 10). Six hours postadministration, xylazine (3 mg/kg) and ketamine (2 mg/kg) was administered intramuscularly via a dart. Rectal temperature, heart rate, respiratory rate, and SpO2 (percent hemoglobin saturation) were recorded at 5-min intervals. Blood gas analysis was performed at time 0 (venous blood) and 10 and 20 min (arterial blood) postinduction. Serum cortisol was determined from venous blood (35 min postinduction), following which yohimbine was administered at a dose of 0.15 mg/kg intramuscular and 0.15 mg/kg intravenous. Statistical analysis of repeated measures data was performed with a two-way analysis of variance. Paired data were analyzed with a Wilcoxon rank-sum test (categorical data) or a paired t-test (continuous data). Significance was set at P ≤ 0.05, and results were expressed as mean ± SEM. There was no significant difference in induction time or recovery time between treatment groups. Rectal temperature and heart rate were significantly lower in the haloperidol group. Both groups demonstrated acidosis with venous pH being significantly lower in the placebo group when compared to the haloperidol group. Serum cortisol and arterial plasma lactate were lower in the haloperidol group indicative of reduced stress and physical exertion. Haloperidol premedication proved to be beneficial in reducing capture stress, when administered prior to xylazine-ketamine anesthesia, in spotted deer.

A randomised controlled trial investigating the effects of administering a non-steroidal anti-inflammatory drug to beef calves assisted at birth and risk factors associated with passive immunity, health, and growth.

BACKGROUND: The objectives of this study were to investigate the impact of pain mitigation at birth to assisted beef calves and determine the risk factors associated with transfer of passive immunity (TPI), health, and growth. METHODS: Two hundred and thirty cow-calf pairs requiring calving assistance were enrolled. Calves were randomised to receive meloxicam (0.5 mg/kg) or an equivalent volume of placebo subcutaneously at birth. Calf blood samples were collected between one and seven days of age to determine serum immunoglobulin (IgG) concentration. Colostrum intake, treatment for disease, mortality, and weaning weights were recorded. Multilevel linear or logistic regression models were used to determine the effects of meloxicam and to identify risk factors. RESULTS: There was no effect of meloxicam on serum IgG concentrations, average daily gain (ADG), or risk of inadequate TPI (serum IgG concentration <24 g/l), treatment for disease, or mortality (P>0.05). Bottle or tube feeding calves were associated with decreased serum IgG concentrations (P=0.01) compared with nursing. Calves with an incomplete tongue withdrawal reflex had higher odds of being treated for disease compared with those with complete withdrawal (P=0.009). Being born meconium-stained and having decreased serum IgG concentrations were associated with an increased risk of mortality (P=0.03). Being born of a mature cow, having a higher birth weight, and increased serum IgG concentrations were associated with greater ADG to weaning (P<0.05). CONCLUSION: Vigour assessment at birth along with good colostrum management may be important to improve TPI and health in high-risk calves such as those assisted at birth.

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.

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.

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.

Assessing the Efficacy of Ventilation of Anesthetized Neonatal Calves Using a Laryngeal Mask Airway or Mask Resuscitator.

Calves that have undergone a dystocia are often hypoxic and acidemic, which can result in reduced vigor and subsequent mortality. Methods of field resuscitation of apneic newborn calves are often ineffective and therefore underutilized. This proof-of-concept study aimed to determine the efficacy of the laryngeal mask airway (LMA) as well as the current industry standard method of ventilation, the McCulloch Calf Aspirator/ Resuscitator (MMR) for positive pressure ventilation of neonatal calves. Five LMA models of various sizes were first tested in cadaver heads to assess anatomical fit. Three LMA models in two sizes each were then tested in two anesthetized calves to determine the model best suited to ventilate calves. Next, the selected LMA and the MMR were both assessed for efficacy of ventilation. Six anesthetized calves had hypoventilation induced by administering alfaxalone intravenously. Calves were ventilated for 3 min with the LMA, allowed a brief washout period, then given a second administration of alfaxalone prior to ventilation with the MMR. Serial arterial blood gas analyses were performed prior to ventilation (baseline), at 1, 2, and 3 min during ventilation, and 1 min after ventilation had ceased. Success of ventilation was assessed by monitoring partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), bicarbonate ( HCO 3 - ), pH, L-lactate, and hemoglobin saturation (SaO2) in arterial blood. A one-way ANOVA for repeated measures with Bonferroni correction was used to assess the efficacy of ventilation of each device compared to baseline. For the LMA, PaO2, SaO2, and pH were significantly higher than baseline throughout ventilation and PaCO2 was significantly lower than baseline at 1 min of ventilation. For the MMR, PaO2 and SaO2 were significantly higher and PaCO2 and HCO 3 - were significantly lower than baseline for 1 to 2 min of ventilation. This proof-of-concept study showed the LMA is an effective means of ventilating neonatal calves, as was the MMR.

COMPARISON OF THE EFFICACY AND SAFETY OF MEDETOMIDINE-KETAMINE VERSUS MEDETOMIDINE-AZAPERONE-ALFAXALONE COMBINATION IN FREE-RANGING ROCKY MOUNTAIN BIGHORN SHEEP ( OVIS CANADENSIS).

Chemical immobilization is a key aspect of wildlife management. To minimize dose-dependent adverse effects, immobilization protocols often include two or more synergistic agents, which allows for reductions in individual drug dosages. Free-ranging bighorn sheep ( Ovis canadensis) in Canada ( n = 74) were remotely injected with a combination of medetomidine (0.16 ± 0.04 mg/kg) and ketamine (4.0 ± 1.4 mg/kg) (MK), or combination of medetomidine (0.14 ± 0.06 mg/kg), azaperone (0.21 ± 0.11 mg/kg), and alfaxalone (0.45 ± 0.21 mg/kg) (MAA). Once recumbency was achieved, arterial blood samples were collected and immediately analyzed for blood gas and acid-base status. Rectal temperature, heart rate, and respiratory rate were recorded upon recumbency and throughout anesthesia at 5-15 min intervals. At conclusion of the procedures, medetomidine was reversed by intramuscular atipamezole at five times the medetomidine dose. Induction times (mean ± standard deviation) of animals that became immobilized with one dart (8.7 ± 3.2 min, 7.3 ± 3.9 min) and recovery times of all animals (3.4 ± 1.5 min, 3.9 ± 1.6 min) were not significantly different between MK and MAA groups, respectively. Both MK and MAA groups experienced severe hypoxemia (PaO2 42 ± 9 mmHg, 40 ± 10 mmHg, respectively). PaCO2 was significantly higher ( P = 0.0248) in the MK group (median 54 mmHg) than the MAA group (median 48 mmHg) with a trend towards lower pH (7.40 vs 7.42, respectively, P = 0.07). Initially, MK animals had higher heart rates than MAA animals (median 49 vs 40 beats/min), which decreased over time. In bighorn sheep, both MK and MAA produced reliable, reversible immobilization with smooth inductions and recoveries. However, less respiratory depression was seen with MAA than MK.

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.

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.

CAPTURE OF FREE-RANGING MULE DEER (ODOCOILEUS HEMIONUS) WITH A COMBINATION OF MEDETOMIDINE, AZAPERONE, AND ALFAXALONE.

The combination of medetomidine, azaperone, and alfaxalone has been successfully used to anesthetize captive white-tailed deer ( Odocoileus virginianus ). This same combination was utilized to immobilize free-ranging female mule deer ( Odocoileus hemionus ; MD) in urban and nonurban environments (14 urban MD, 14 nonurban MD) in British Columbia, Canada. Physiologic data were collected to assess the safety and reliability of this drug combination under field conditions. Each deer received estimated dosages of 0.15 mg/kg medetomidine, 0.2 mg/kg azaperone, and 0.5 mg/kg alfaxalone intramuscularly via a remote darting system. Inductions were calm and rapid (mean time to sternal recumbency: urban MD, 6.4±2.2 min; nonurban MD, 8.2±4.1 min). Supplemental drugs were required to induce lateral recumbency in five deer, four of which had experienced initial dart failure (mean time to lateral recumbency: urban MD, 8.5±3.8 min; nonurban MD, 18.7±16.5 min). Recoveries were smooth and uneventful (time to standing: urban MD, 12.5±3.4 min; nonurban MD, 9.0±3.5 min) for all but one debilitated nonurban MD that died shortly after atipamezole administration (at five times the medetomidine dose). The major side effects of the combination were hypoxemia and hypercapnia. The combination of medetomidine, azaperone, and alfaxalone proved suitable for the immobilization of urban and nonurban free-ranging MD.

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).

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.