Sedation of wild boar (Sus scrofa) and red deer (Cervus elaphus) with medetomidine and the influence on some haematological and serum biochemical variables

Use of Wild Ungulates as Sentinels of TBEV Circulation in a Naïve Area of the Northwestern Alps, Italy

Wild and domestic animals can be usefully employed as sentinels for the surveillance of diseases with an impact on public health. In the case of tick-borne encephalitis virus (TBEV), the detection of antibodies in animals can be more effective than screening ticks for detecting TBEV foci, due to the patchy distribution of the virus. In the Piedmont region, northwestern Italy, TBEV is considered absent, but an increase in tick densities, of Ixodes ricinus in particular, has been observed, and TBEV is spreading in bordering countries, e.g., Switzerland. Therefore, we collected sera from wild ungulates during the hunting season (October-December) from 2017 to 2019 in the Susa Valley, Italian western Alps, and screened them for TBEV antibodies by a commercial competitive ELISA test. We collected 267 serum samples by endocranial venous sinuses puncture from red deer, roe deer and northern chamois carcasses. The animals were hunted in 13 different municipalities, at altitudes ranging between 750 and 2800 m a.s.l. The serological survey for TBEV yielded negative results. Borderline results for five serum samples were further confirmed as negative for TBEV by a plaque reduction neutralisation test. To date, our results indicate that TBEV is not circulating in western Piedmont. However, monitoring of TBEV should continue since TBEV and its vector are spreading in Europe. The wide-range distribution of wild ungulates and their role as feeding hosts, make them useful indicators of the health threats posed by Ixodid ticks.

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

OBJECTIVE

To 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 DESIGN

Randomized, blinded, crossover study.

ANIMALS

A group of nine healthy Patagonian maras (Dolichotis patagonum).

METHODS

Maras 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).

RESULTS

Vatinoxan 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 RELEVANCE

In 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.

SERUM BIOCHEMISTRY VALUES AND SELECT SEROLOGIC SCREENING OF BROWN HYENAS ( PARAHYAENA BRUNNEA) FROM THE NAMIB DESERT, NAMIBIA

Blood from 30 free-ranging brown hyenas ( Parahyaena brunnea) was collected for biochemical analysis and select serologic screening in Namibia from 1997 to 2010. Age was found to have an influence on several biochemical parameters that may be related to growth, a developing immune system, and differences in diet. Seasonal differences in diet of coastal brown hyenas also had an overall significant effect on lipemia values, and differences in stress due to varying capture methods could be associated with an increase in glucose and creatinine kinase. Comparisons among hyena species from published data were inconclusive, as some samples may have been derived from captive populations and individuals. Sera were tested for antibodies against 18 pathogens. Antibodies were not detected for most pathogens, but the proportion of sera containing antibodies against canine adenovirus-1 (CAV-1) and canine adenovirus-2 (CAV-2) was 65% and 84%, respectively. There was no effect of sex, age, year of sampling, or contact with domestic dogs, indicating that CAV-1 or CAV-2 may be enzootic. The prevalence of antibodies to canine distemper virus (CDV) was 43%, and older brown hyenas were 6.9 times more likely to have been exposed to CDV, adjusting for year of sampling and degree of estimated contact with domestic dogs, suggesting epizootic outbreaks. This study is the first to present biochemical reference intervals for wild brown hyenas and provides an indication of disease exposure in this species.

Hematologic Parameters and Viral Status for Zika, Chikungunya, Bluetongue, and Epizootic Hemorrhagic Disease in White-tailed Deer ( Odocoileus virginianus) on St. John, US Virgin Islands

A population of white-tailed deer ( Odocoileus virginianus) resides throughout the island of St. John, US Virgin Islands, predominately in the Virgin Islands National Park. Adult deer ( n=23), ranging from 1 yr to 8 yr old, were assessed to characterize body condition and health. Serologic samples were screened for important viral pathogens in the area, including Zika, chikungunya, bluetongue, and epizootic hemorrhagic disease viruses. Samples were collected in July 2016; males were in velvet and all females were in diestrus. Deer had recovered from a severe drought the previous year but were generally healthy, with a low-level but high incidence of tick parasitism. Marked statistically significant changes in hematocrit and hemoglobin levels were associated with the effects of the anesthetic mixture used for capture. No other statistically significant differences were observed. Serum from four deer induced reduction in Zika virus plaques, suggesting possible exposure. No serum was reactive for chikungunya virus. Bluetongue and epizootic hemorrhagic disease antibodies were present in 50% of the sampled deer, but no clinical signs associated with disease were observed during the study period. These data will be valuable for future dynamic health assessment and may help assess changes to the population, such as those induced by climate change, infectious disease, or other demographic events.

Hematologic and biochemical reference intervals for Wild Boar (Sus scrofa) captured by cage trap

BACKGROUND

Establishing reference intervals (RI) for hematologic and biochemical variables in wild animals presents great challenges because capture stress or anesthesia during sampling can affect blood variables.

OBJECTIVES

The aims of this study were to establish RI for hematologic and blood biochemistry variables for Wild Boar (Sus scrofa) caught using cage traps, and provide information on the studied variables for different age groups.

METHODS

Blood samples were obtained from 89 Wild Boars captured by cage trap between 2005 and 2013 in northeastern Spain. Piglets were handled without anesthesia, while juvenile and adult animals were anesthetized using a combination of tiletamine and zolazepam. Blood samples were collected from the anterior vena cava and were placed into plain and EDTA tubes. Thirteen hematologic and 21 biochemical variables were determined. Reference intervals for piglets and juvenile and adult groups were determined, and differences between these groups were statistically analyzed.

RESULTS

Adults had higher HGB, PCV, MCH, MCHC, neutrophil count, and total protein, albumin, creatinine, and chloride concentrations than juveniles; in contrast, juveniles had higher values for lymphocyte count, cholesterol concentration, and ALP activity.

CONCLUSIONS

Reference intervals determined in this study provide a baseline for interpreting hematologic and biochemical results in Wild Boar at different age stages, and contribute to optimization of the management of this species.

Haematological and biochemical reference intervals for free-ranging brown bears (Ursus arctos) in Sweden

Background

Establishment of haematological and biochemical reference intervals is important to assess health of animals on individual and population level. Reference intervals for 13 haematological and 34 biochemical variables were established based on 88 apparently healthy free-ranging brown bears (39 males and 49 females) in Sweden. The animals were chemically immobilised by darting from a helicopter with a combination of medetomidine, tiletamine and zolazepam in April and May 2006–2012 in the county of Dalarna, Sweden. Venous blood samples were collected during anaesthesia for radio collaring and marking for ecological studies. For each of the variables, the reference interval was described based on the 95% confidence interval, and differences due to host characteristics sex and age were included if detected. To our knowledge, this is the first report of reference intervals for free-ranging brown bears in Sweden.

Results

The following variables were not affected by host characteristics: red blood cell, white blood cell, monocyte and platelet count, alanine transaminase, amylase, bilirubin, free fatty acids, glucose, calcium, chloride, potassium, and cortisol. Age differences were seen for the majority of the haematological variables, whereas sex influenced only mean corpuscular haemoglobin concentration, aspartate aminotransferase, lipase, lactate dehydrogenase, β-globulin, bile acids, triglycerides and sodium.

Conclusions

The biochemical and haematological reference intervals provided and the differences due to host factors age and gender can be useful for evaluation of health status in free-ranging European brown bears.

Trap-effectiveness and response to tiletamine-zolazepam and medetomidine anaesthesia in Eurasian wild boar captured with cage and corral traps

Background

Capture, handling and chemical restraint are basic techniques often needed for research or management purposes. The aim of this study was testing a combination of tiletamine-zolazepam (TZ) (3 mg/kg) and medetomidine (M) (0.05 mg/kg) on Eurasian wild boar (Sus scrofa). A total of 77 free-ranging wild boar were captured by means of portable cages and corral traps and then anaesthetized with intramuscular darts using a blowpipe. The individual response to chemical immobilization was characterized using anaesthetic, clinical, and serum biochemical variables. After the procedure, 14 of these wild boar were monitored for 20 days using GPS-GSM collars.

Results

Pre-release mortality during capture and handling (6.5%) was associated with severe trauma in corral traps. Capture specificity for wild boar was 96.3% and trapping effort was 16.5 days per captured wild boar. Mean induction period was 4.5 ± 2.2 min, hypnosis period enabling effective handling was 61.6 ± 25.4 min, and recovery period was 12.8 ± 12.1 min. No heart or respiratory failure due to added stress occurred and post-release monitoring by GPS-devices revealed no mortality due to anaesthesia. According to the best statistical model obtained, the main factor driving anaesthetic efficacy and stress indicators is trap type.

Conclusions

Both cage and corral traps are efficient methods to capture wild boar. Cage traps are safer, as demonstrated by mortality rates as well as anaesthetic, physiological, and serum biochemical responses. This anaesthetic protocol is useful for prolonged handling of wild boar and allows sampling and collecting data for ecological and epidemiological studies.

Effects of physical and chemical immobilization on hematologic and biochemical variables in captive brown brocket deer (Mazama gouazoubira)

BACKGROUND

Alterations in cellular and chemical constituents in blood are indicators of physical or chemical restraint in deer.

OBJECTIVES

The aim of this study was to determine the effects of physical and chemical restraint on hematologic and biochemical analytes in captive brown brocket deer (Mazama gouazoubira).

METHODS

Six adult deer were physically restrained and randomly anesthetized in a crossover design using 3 protocols (P). In P1, anesthesia was induced directly with isoflurane using a face mask and was maintained with isoflurane delivered by endotracheal tube. In P2, oral premedication with midazolam was followed 1 hour later by induction and maintenance of anesthesia with isoflurane, as in P1. In P3, intravenous anesthesia with a combination of ketamine, xylazine, and atropine was followed by anesthesia with isoflurane, as in P1. Blood was collected immediately after physical restraint (T0) and during anesthesia at 20-minute intervals (T15, T35, and T55). Hematologic and biochemical constituents were determined using manual methods or automated analyzers, with cortisol measured by enzyme immunoassay.

RESULTS

During physical restraint, following food and water restriction, significant hemoconcentration, increased WBC count, and lower cortisol concentration were observed compared with results at T15, T35, and T55. During anesthesia, lymphocyte count was lower in P2 than P1, urea concentration was decreased at T15 using P2, and plasma glucose concentration was increased after T0 (P<.01). Among the anesthetic protocols, there was a trend for decreased cortisol concentration using P2.

CONCLUSIONS

Physical restraint and anesthesia affect some blood constituents in captive brown brocket deer, and midazolam premedication may modify the intensity of the stress response.

The use of a medetomidine, butorphanol and atropine combination to enable blood sampling in young pigs

AIM

To determine the suitability of a reversible, injectable anaesthetic combination including medetomidine, butorphanol and atropine to produce the degree of immobilisation required to allow blood sampling in young pigs.

METHODS

Twenty 6-week-old crossbred, intact male pigs were sedated with an intramuscular (I/M) injection of 80 microg/kg medetomidine, 200 microg/kg butorphanol and 25 microg/kg atropine. Heart and respiratory rates and rectal temperatures were monitored. Excessive salivation, gagging, laryngeal reflex, presence of pedal reflex and deep and surface analgesia were noted. Time of injection and the time when pigs reached mild and full sedation were also recorded.

RESULTS

Mild sedation was produced in 90% of pigs after 5.6 (SEM 0.96) min (n = 18; median 5, range 2-16 min), and full sedation (lateral recumbency and loss of jaw tone) in 60% of pigs after 12.5 (SEM 2.14) min (n = 12; median 10, range 5-28 min). The depth and duration of sedation were very variable and most animals were easily aroused. Ninety percent of the animals required the administration of halothane by mask to allow blood sampling, but the amount of halothane required was small. Heart and respiratory rates decreased (p < 0.001) but remained within the normal range. Rectal temperature was above normal at the time of sedation and at the time of blood sampling when the ambient temperature was 29 degrees C but not when the ambient temperature was reduced to 25 degrees C.

CONCLUSIONS

The combination of medetomidine, butorphanol and atropine at these doses produced sedation of variable depth and duration that was insufficient on its own to allow blood sampling in the majority of pigs. Hyperthermia can occur in temperature-controlled environments when using medetomidine, butorphanol and atropine in pigs. Reduction of stress and a quieter environment may improve the effects of the anaesthetic combination.

Effects of dexmedetomidine on adrenocortical function, and the cardiovascular, endocrine and inflammatory responses in post-operative patients needing sedation in the intensive care unit

We have compared the effects of dexmedetomidine and propofol on endocrine, metabolic, inflammatory and cardiovascular responses in patients in the intensive care unit (ICU) after major surgery. Twenty patients who were expected to require 8 h of post-operative sedation and ventilation were allocated randomly to receive either an infusion of dexmedetomidine 0.2-2.5 microg kg(-1) h(-1) or propofol 1-3 mg kg(-1) h(-1). Arterial pressure, heart rate and sequential concentrations of circulating cortisol, adrenocorticotrophic hormone (ACTH), growth hormone, prolactin, insulin, glucose and interleukin 6 were measured. An ACTH stimulation test was performed in all patients who received dexmedetomidine. Heart rate was significantly lower in the dexmedetomidine patients. There were no differences in arterial pressure, cortisol, ACTH, prolactin and glucose concentrations between the two groups. A positive response to the ACTH stimulation test varied depending on the diagnostic criteria used. The insulin concentration was significantly lower in the dexmedetomidine group at 2 h (P=0.021), although this did not affect blood glucose concentrations. Growth hormone concentrations were significantly higher in dexmedetomidine-treated patients overall (P=0.036), but circulating concentrations remained in the physiological range. Interleukin 6 decreased in the dexmedetomidine group. We conclude that dexmedetomidine infusion does not inhibit adrenal steroidogenesis when used for short-term sedation after surgery.

Chemical immobilization of felids, ursids, and small ungulates

Private ownership of wild animals is on the rise. With the advent of potent new sedative agents, many practitioners now receiving these cases have the means to increase the safety and effectiveness of chemical immobilization in many wildlife species. Chemical immobilization is actually the induction of anesthesia. In many cases, induction alone suffices to achieve some management or medical goal, whereas in other cases, maintenance anesthesia is required. One quickly realizes that once these species are induced, maintenance anesthesia is often familiar, based on experiences with domestic animals that bear close similarity to the species discussed in this chapter. Induction and recovery of wild animals requires special attention to details to prevent "fight or flight" responses from marring the success of a sedation procedure. Although potent novel drugs allow veterinarians to expand their practice horizons, it is vital to evaluate legal and safety issues thoroughly before engaging in the care of wildlife species on a regular basis.

Effect of the method of capture on the haematology and blood chemistry of red deer (Cervus elaphus)

Haematological and plasma biochemical constituents can be affected during capture and handling operations in wildlife. The present study compares the blood constituents of 40 red deer (Cervus elaphus) captured using two different methods: 20 were captured by physical means, using long nets and box traps, and 20 by chemical means, using a mixture of xylazine and ketamine. Significant differences were found in the haemogram: red blood cell count, packed cell volume, haemoglobin concentration, and segmented neutrophil, lymphocyte, monocyte and total leukocyte counts were higher in animals captured by physical means. Conversely, the eosinophil count was higher in deer captured using anaesthetic. The plasma activity of alanine amino transferase, and the concentrations of cholesterol, triglycerides, albumin, alpha-2 globulins, total proteins, sodium and chloride, were significantly higher in the group captured by physical means. With the exception of the eosinophil count, all the blood constituents which presented higher values were in the group of physically captured deer, and thus it is necessary to take into account the method of capture when interpretation or establishment of reference values is performed.