Physiologic Evaluation of Medetomidine-Ketamine Anesthesia in Free-ranging Svalbard ( Rangifer tarandus platyrhynchus ) and Wild Norwegian Reindeer ( Rangifer tarandus tarandus )

RESPONSE AND PHYSIOLOGIC OUTCOMES AFTER BUTORPHANOL, MIDAZOLAM, AND MEDETOMIDINE IMMOBILIZATION AND REVERSAL IN CAPTIVE REINDEER (RANGIFER TARANDUS)

Sedation, recovery response, and physiologic outcomes were evaluated in five captive reindeer (Rangifer tarandus) in Minnesota using a completely reversible immobilization protocol. Reindeer were immobilized with butorphanol (0.23-0.32 mg/kg), midazolam (0.23-0.32 mg/kg), and medetomidine (0.15 mg/kg) (BMM) via IM dart. Induction time (IT), recumbency time (DT), and recovery time (RT) were recorded. Temperature (T), respiratory rate (RR), pulse rate (PR), pulse oximetry (SpO2), arterial blood gas values including oxygen (PaO2), and carbon dioxide (PaCO2) tensions and lactate (Lac) were recorded preoxygen supplementation and 15 min postoxygen supplementation. Reversal was done using naltrexone (2.3-3.0 mg/kg), flumazenil (0.008-0.01 mg/kg) and atipamezole (0.62-0.78 mg/kg) (NFA) IM, limiting recumbency to 1 h. Median IT, DT, and RT were 5 min, 46 min, and 7 min, respectively. SpO2 (92 to 99%, P = 0.125), PaO2 (45.5 to 97 mmHg, P = 0.25), and PaCO2 (46.5 to 54.6 mmHg, P = 0.25) all increased, whereas Lac (3.02 to 1.93 mmol/L, P = 0.25) decreased between baseline and 15 min postoxygen supplementation, without statistical significance. BMM immobilization, and reversal with NFA provided rapid and effective immobilization and recovery, respectively. Oxygen supplementation mitigated hypoxemia in all reindeer.

Arterial oxygenation and acid-base status before and during oxygen supplementation in captive European bison (Bison bonasus) immobilized with etorphine-acepromazine-xylazine

Chemical immobilization of captive European bison (Bison bonasus) is often required for veterinary care, transportation, or husbandry practices playing an important role in conservation breeding and reintroduction of the species. We evaluated the efficiency and physiological effects of an etorphine-acepromazine-xylazine combination with supplemental oxygen in 39 captive European bison. Animals were darted with a combination of 1.4 mg of etorphine, 4.5 mg of acepromazine, and 20 mg of xylazine per 100 kg based on estimated body mass. Arterial blood was sampled on average 20 min after recumbency and again 19 min later and analyzed immediately with a portable i-STAT analyzer. Simultaneously, heart rate, respiratory rate, and rectal temperature were recorded. Intranasal oxygen was started after the first sampling at a flow rate of 10 mL.kg^-1.min^-1 of estimated body mass until the end of the procedure. The initial mean partial pressure of oxygen (P_aO₂) was 49.7 mmHg with 32 out of 35 sampled bison presenting with hypoxemia. We observed decreased respiratory rates and pH and mild hypercapnia consistent with a mild respiratory acidosis. After oxygen supplementation hypoxemia was resolved in 21 out of 32 bison, but respiratory acidosis was accentuated. Bison immobilized with a lower initial drug dose required supplementary injections during the procedure. We observed that lower mean rectal temperatures during the immobilization event were significantly associated with longer recovery times. For three bison, minor regurgitation was documented. No mortality or morbidity related to the immobilizations were reported for at least 2 months following the procedure. Based on our findings, we recommend a dose of 0.015 mg.kg^-1 etorphine, 0.049 mg.kg^-1 acepromazine, and 0.22 mg.kg^-1 xylazine. This dose reduced the need for supplemental injections to obtain a sufficient level of immobilization for routine management and husbandry procedures in captive European bison. Nevertheless, this drug combination is associated with development of marked hypoxemia, mild respiratory acidosis, and a small risk of regurgitation. Oxygen supplementation is strongly recommended when using this protocol.

Plasmid-associated antimicrobial resistance and virulence genes in Escherichia coli in a high arctic reindeer subspecies

OBJECTIVES

In extreme environments, such as the Arctic region, the anthropogenic influence is low and the presence of antimicrobial-resistant bacteria is unexpected. In this study, we screened wild reindeer (Rangifer tarandus platyrhynchus) from the Svalbard High Arctic Archipelago for antimicrobial-resistant Escherichia coli and performed in-depth strain characterisation.

METHODS

Using selective culturing of faecal samples from 55 animals, resistant E. coli were isolated and subjected to minimum inhibitory concentration (MIC) determination, conjugation experiments and whole-genome sequencing.

RESULTS

Twelve animals carried antimicrobial-resistant E. coli. Genomic analysis showed IncF plasmids as vectors both for resistance and virulence genes in most strains. Plasmid-associated genes encoding resistance to ampicillin, sulfonamides, streptomycin and trimethoprim were found in addition to virulence genes typical for colicin V (ColV)-producing plasmids. Comparison with previously reported IncF ColV plasmids from human and animal hosts showed high genetic similarity. The plasmids were detected in E. coli sequence types (STs) previously described as hosts for such plasmids, such as ST58, ST88 and ST131.

CONCLUSION

Antimicrobial-resistant E. coli were detected from Svalbard reindeer. Our findings show that successful hybrid antimicrobial resistance-ColV plasmids and their host strains are widely distributed also occurring in extreme environmental niches such as arctic ecosystems. Possible introduction routes of resistant bacterial strains and plasmids into Svalbard ecosystems may be through migrating birds, marine fish or mammals, arctic fox (Vulpes lagopus) or via human anthropogenic activities such as tourism.

CARDIORESPIRATORY EFFECTS OF DEXMEDETOMIDINE-MIDAZOLAM AND REVERSAL WITH ATIPAMEZOLE IN CAPTIVE BROWN BROCKET DEER (MAZAMA GOUAZOUBIRA)

Ketamine-free, midazolam-based protocols have successfully immobilized cervids in the past but their impact on physiological function has not yet been thoroughly investigated. Six deer received IM dexmedetomidine (30.96 ± 3.06 µg/kg) and midazolam (0.31 ± 0.03 mg/kg). Heart rates (HR), respiratory rates (f ), rectal temperature, mean arterial blood pressure (MAP), and oxygen saturation (SpO₂) were recorded 25 min after drug delivery (T25) and every 5 min until T55. An arterial blood sample was collected at T40. Mean HR and temperature significantly decreased throughout sedation, but were maintained above critical values (> 60 beats/ min and 37°C, respectively). Although not statistically different, f clinically decreased during sedation. MAP remained within acceptable ranges (60-80 mmHg) and SpO₂ above 95%. Mean PaO₂ was normal (>80 mmHg), but a mild hypoxemia was observed on two occasions. Recovery was smooth yet prolonged, as the first head movement, attempt to stand, sternal recumbency, and standing position were recorded within 9.36 ± 3.47, 10.32 ± 1.37, 13.13 ± 2.70, and 15.34 ± 2.57 min after IM atipamezole, respectively. This protocol was effective for short-term procedures in captive brown brocket deer, and appeared to be safe on the basis of arterial blood gases and cardiorespiratory variables.

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine-Ketamine

Semidomesticated Eurasian tundra reindeer (Rangifer tarandus tarandus, n = 21) were scheduled twice for chemical immobilization with medetomidine–ketamine as part of a scientific experiment in June 2014. During the first round of immobilizations, seven animals developed severe respiratory depression (RD). Three individuals died, and 4 recovered. The ambient temperature during the 2 days of immobilization (June 3 and 4) was high (mean 13.9–17.6°C) compared to the normal mean temperature for these 2 days (7–8°C) based on statistical records. During the second round of immobilizations, using the same anesthetic protocol for the remaining animals as in the first round but conducted under cooler conditions (mean 6.6°C for the period June 9–18), no signs of RD were observed. Clinical and pathological investigations indicated that the animals suffered from circulatory changes possibly caused by high ambient temperatures and granulomatous interstitial pneumonia due to Elaphostrongylus rangiferi larvae. These conditions, together with the cardiovascular effects of medetomidine, were likely causes of RD and the fatal outcome. We conclude that chemical immobilization of reindeer with medetomidine–ketamine should be avoided in May–June due to the potential risk when animals partly in winter coats encounter rising ambient temperatures and usually have parasites developing in their airways.

Immobilization of captive Persian fallow deer (Dama dama mesopotamica) using medetomidine-ketamine or medetomidine-midazolam

OBJECTIVE

To establish and compare the effectiveness of two medetomidine-based immobilization protocols in Persian fallow deer (Dama dama mesopotamica).

STUDY DESIGN

Prospective, randomized, blinded clinical study.

ANIMALS

A group of 31 captive Persian fallow deer.

METHODS

Deer scheduled for translocation were immobilized with a combination of medetomidine (76 ± 11 μg kg^-1) and ketamine (1.0 ± 0.2 mg kg^-1) (MK; n = 15) or medetomidine (77 ± 11 μg kg^-1) and midazolam (0.10 ± 0.01 mg kg^-1) (MM; n = 16) administered intramuscularly. An observer unaware of group assignments recorded times to immobilization and recovery, monitored physiologic variables and scored the quality of induction, immobilization and recovery (scale 1-5: 1, poor; 5, excellent). Atipamezole was administered for reversal. Data analysis was performed using the t test, the Mann-Whitney U test, the chi-square test and the Fisher's exact test. Significance was set at p < 0.05.

RESULTS

Data are presented as mean ± standard deviation or median (range). Time to induce immobilization was 9 ± 4 and 10 ± 4 minutes in the MK and MM groups, respectively. Immobilization quality score was 5 (1-5) following both combinations. Hemoglobin oxygen saturation (SpO₂) was significantly lower in the MK (80 ± 8%) than in the MM group (87 ± 8%) although respiratory frequency did not differ between MK and MM (11 ± 5 and 10 ± 2 breaths minute^-1, respectively). Recovery times were 13 ± 6 (MK) and 14 ± 7 minutes (MM) and did not differ between groups. No morbidities or mortalities were recorded during 1 month after immobilization.

CONCLUSIONS AND CLINICAL RELEVANCE

The MK and MM combinations produced sufficient immobilization in captive Persian fallow deer for short nonpainful procedures. Based on the SpO₂ values, the MM combination may be associated with less respiratory depression; nevertheless, both combinations may result in a decrease in SpO₂.

Endotracheal tube obstruction with a blood clot following aspiration of rumen contents in a reindeer

Summary

An apparently otherwise healthy female reindeer was anaesthetised for open reduction and fixation of a hip luxation. The animal developed ruminal bloat which was treated with passage of an orogastric tube that was left indwelling during the procedure. A fluid inspiratory noise was audible two hours after decompression, and clear fluid was suctioned from the airway. It showed no other signs of regurgitation and aspiration of rumen contents intraoperatively, and did not develop obvious respiratory compromise while mechanically ventilated. In recovery, the deer became apnoeic and cyanotic and died suddenly within minutes of being positioned in the recovery box. Just before dying, it coughed a large blood clot out of the endotracheal tube (ETT) . Additional clots were found partially obstructing the ETT lumen once extubated postmortem. Evidence of aspiration was detected at postmortem examination, which also identified pulmonary haemorrhage.

Effective thiafentanil immobilization and physiological responses of free-ranging moose (Alces alces) in northern Sweden

OBJECTIVE

To evaluate clinical and physiological responses in moose to thiafentanil administration for immobilization.

STUDY DESIGN

Cross-sectional clinical study.

ANIMALS

Eleven (six males and five females) free-ranging adult moose (Alces alces).

METHODS

Each moose was darted from a helicopter with 7.5 mg thiafentanil during March 2014 in northern Sweden. Physiological evaluation included vital signs and blood gases. Arterial blood was collected after induction and again after 10 minutes of intranasal oxygen administration and analyzed immediately with an i-STAT analyzer. A total of 10 mg naltrexone per milligram of thiafentanil was administered to all animals for reversal. Data were analyzed using descriptive statistics.

RESULTS

All moose were sufficiently immobilized with a single dart injection. Induction occurred within 3 minutes in 10 of 11 moose. One individual became recumbent while crossing a river and naltrexone was immediately administered. Animals maintained sternal recumbency with their head raised and vital signs were stable. Nine of 10 moose were hypoxemic before oxygen administration, with seven becoming markedly hypoxemic [partial pressure of arterial oxygen (PaO₂) between 40 and 59 mmHg (5.3-7.9 kPa)]. The PaO₂ increased significantly between samples, but six moose remained hypoxemic despite therapy. Hypercapnia was seen in all moose, with eight having marked hypercapnia [partial pressure of arterial carbon dioxide (PaCO₂) > 60 mmHg (>8.0 kPa)]. All moose were acidemic, with nine showing marked acidemia (pH < 7.20). The pH increased significantly with time and lactate decreased. Recoveries were rapid and uneventful, and all moose were living 6 months after capture.

CONCLUSIONS

Thiafentanil provided rapid and sufficient immobilization of moose and its effects were rapidly reversed with naltrexone. As with other opioids, moose showed hypoxemia and varying degrees of respiratory and metabolic acidosis. Arterial oxygenation of moose improved following intranasal oxygen, but hypoxemia was not fully resolved despite therapy.

CLINICAL RELEVANCE

Thiafentanil (7.5 mg per adult) is effective for immobilization of free-ranging moose. Supplemental oxygen may be of benefit when using this regimen; however, further investigation is required to confirm these results.