Taxonomy

A variety of the species covered in this order are not primarily carnivores. Many species of this order are popular as exhibit animals as well as exotic pets lending the private practitioner exposure to these owners or as refuge/ rescue patients. Below is an abbreviated list of the families and example species.

 Order Carnivora- Family Canidae: non-domestic dogs, fox, wolf

 Order Carnivora- Family Ursidae: bear, giant panda

 Order Carnivora- Family Aluridae: lesser panda

 Order Carnivora- Family Procyonidae: raccoon, kinkajou

 Order Carnivora- Family Mustelidae: skunk, otter, ferret, weasel

 Order Carnivora- Family Viveridae: civet, meerkat, mongoose

 Order Carnivora- Family Hyaenidae: hyena

 Order Carnivora- Family Felidae: non-domestic felids

Legal and Safety Precautions

It is important to consider the philosophical, legal, and ethical implications of working with many of these species for you, your staff, and your clients. You need to feel comfortable that this working relationship with your clients owning these species has full disclosure from a safety standpoint for both you and your staff. Ethical issues such as declawing and canine extractions need to be considered before your frontline staff receives the call. Utilize policies developed by the American Veterinary Medical Association (www.avma.org) and American Association of Zoo Veterinarians (www.aazv.org) as guides for your practice. Finally, keep abreast of the legal limitations regarding the species you are being asked to evaluate. Dr. Adolf Maas provides an excellent overview in Veterinary Clinics Exotic Animal Practice of the legal implications of exotic pet practice.

Many of these species have significant risk for human safety in regard to containment and restraint. They are quite nimble making physical restraint often challenging regardless of animal size. Bacterial infections are a serious risk with bite wounds and should be treated as such with appropriate care.

Physical Restraint

Maximize your success of restraint while minimizing human safety risk by utilizing squeeze crates, restraint poles and boards, and nets if physical restraint is required prior to chemical restraint. Several of these species can be easily trained for non-invasive evaluations such as weights, limited physical exams, IM injections, and blood collections. Often these techniques can provide valuable information for your examination or as a pre-anesthetic evaluation and can minimize the stress associated with veterinary care. Generally, smaller species (<10 kg) can be physically restrained (with the help of a net and bite gloves), larger species (10-45 kg) should be physically restrained with caution on a case by case basis but can be done utilizing restraint poles or boards and bite gloves briefly for hand-injection of anesthetic agents. Squeeze cages are useful for many of these species and are the primary means of physical restraint for bears and large felids. In field conditions, humane legs traps, nets and snares are used and policies in their usage can be referenced at the AAZV website. In captive conditions, without operant conditioning of these larger species or squeeze crate capabilities, remote systems such as pole syringes or darts will be needed. Firearms backup should be seriously considered when immobilizing large carnivores in case of unexpected return to consciousness.

Chemical Restraint and Anesthesia

Considerations: In contrast to other zoo and wildlife species, much of the information in the domestic literature can be extrapolated to most of these carnivore species. Use your comparative medicine skills to your advantage when working with these species. The same principles used in domestic dog and cat medicine apply with some notable exceptions reported in the literature and mentioned below. Excellent resources exists in the literature that are family- specific and fairly comprehensive in nature including excellent references.^{1,3,4,5,6,7,8} The species variability as well as the clinical presentation of will play a significant role in the strategy for chemical restraint including drug choices and dosages needed.

Pre-anesthetic fasting for 12 hrs is recommended for most medium to large carnivore species. This is a recognized as an over-generalization and should be decreased to 4-8 hours for smaller species.

 As a general rule, keeping the animal stress-free or relatively calm will translate to needing to use less anesthetic and provide a smoother anesthetic induction.

 The mental state of the animal needs to also be factored into the drug and dose choices as an excited or agitated animal will often times require higher dose/ dosages that the trained animal receiving a hand injection under "comfortable" conditions. Alternatively, a debilitated animal may require much less.

 Natural history should be considered with certain family groups in regards to approach to anesthesia

 Canids, viverrids, and hyeanids are typically pack species by nature and prolonged separation should be minimized to reduce reintroduction issues after recovery.

 Muzzles are not recommended for exotic canid species as it prevents their ability to pant and can lead to hyperthermia

 Canids and ursids go through a seasonal torpor or hibernation and this may affect body condition, fat deposits, and metabolic rates.

 A viverrid species, the binturong, has a prehensile tail and can use it with agility during times of restraint, even when sedated.

 Hyeanids are a unique combination in comparative medicine in that size and body structure is similar to canids, however, anatomy and physiology are more like felid species. Veterinarians should use restraint techniques suitable for dogs, but utilize domestic cat references for drug choices and dosages.

 The phenothiazines class (i.e. acepromazine) should be used with caution in many carnivore species due to the interference with thermoregulation and risk of hyperthermia during outdoor procedures with higher ambient temperatures.

 Tiger species appear to have more anesthetic complications than other carnivore species. Telazol should not be administered to tigers due to reports of neurologic signs such as seizures, ataxia and death (often 2-4 days post- anesthesia). Idiosyncratic reactions to higher dosages of naltrexone have been anecdotally reported in tigers and other felid species at higher dosages.

 In some felid species, such as tigers, cougars, and cheetahs, hyperkalemia has been reported during anesthetic event with a normokalemic state prior to procedure which can contribute to complications such as arrhythmias and cardiac arrest.

 Alpha-2 agonists have been reported in limited anecdotes to induce heaving and/or vomiting in some felid species. At higher dosages, suspected cardiovascular compromise has been anecdotally reported in larger felids such as tigers and lions. It is speculated that this could be linked to the compensatory bradycardia.

 When referring to published drug dosages, it is useful to know if the animal was free-ranging or captive, if the protocol was utilized only to render an animal recumbent for subsequent intubation and inhalant anesthesia, or if the dosage was used to achieve immobilization throughout the animal handling procedure (i.e. field anesthesia).

 The incredible size range variation in this group of animals also needs to be considered when dosing any drug. Ideally, age and weight of the individual prior to anesthesia plan development is needed for this consideration.

 When utilizing dart delivery systems in bear species or over-conditioned felids, avoid the hip/ thigh region for dart placement due to fat deposition and increased risk of erratic absorption of anesthetic drugs.

 Intubation is similar to domestic species with careful consideration of laryngospasm by using topical anesthetics. It is a good practice to utilize mouth gags at all times prior to and during intubation/ extubation to minimize the risk of human safety compromise.

 Monitor core body temperature as soon as possible and during the anesthetic event to recognize hyperthermic and hypothermic events quickly for immediate treatment.

 During induction and maintenance of anesthesia, eye covers should be utilized to minimize any visual stimulation and reduce excitation of the animal during restraint.

 Transport of carnivores during anesthesia should be carefully considered with secondary containment as a precautionary recommendation (i.e. crate, closed vehicle, catch pole).

Premedications: The use of premedications may make anesthetic induction smoother, both from a handling point of view as well as decreasing the amount of drug needed to induce anesthesia. Commonly used pre-anesthetics are similar to domestic species and are reported in Table 1. In a healthy animal, the owner may give oral pre- medications at home approximately 30-60 minutes before presentation. It must be stressed to the owner that they cannot be given in a large volume of food or liquid because of increasing the chances of regurgitation and vomiting during anesthetic induction.

Tranquilizers and anesthetics: In small carnivore species, anesthetic chamber induction may be performed. These species can be trained to transfer into an induction chamber for gas administration. It is important to remember that "stress", hyperthermia and emesis may occur. The chamber must be secured and escape- proof.

Below are general descriptions on the most common drug classes used in carnivores.

 Dissociatives such as ketamine has traditionally been the drug of choice alone or in combination with other classes. It is generally safe, inexpensive, and allows for adequate restraint for minor procedures or to enable safe handling until animal can be placed on inhalant anesthesia. Alone, it has been know to cause rough inductions and recoveries, hypersalivation, muscle stiffness, and paroxysmal head movements. If used in combination with reversible anesthetics, it is critical that the Ketamine be metabolized before reversal is given (typically 30-45 minutes post- administration if given IM). Ketamine is available in more concentrated solutions, traditionally 200mg/ml versus the standard 100 mg/ml, from compounding pharmacies. One disadvantage of Ketamine is the lack of a reversal agent.

 Benzodiazepines (diazepam, midazolam, zolazepam) are excellent sedatives and are typically used in combination with the dissociative class to smooth out and quicken inductions. This class is reversible with Flumazenil, (American Pharmaceutical Partners Inc. Schaumburg, IL 60173 USA) a relatively expensive benzodiazepine receptor antagonist. The short half-life of Flumazenil (approx. 1 hr) makes repeated dosing sometimes necessary.

 Tiletamine + zolazepam (Telazol: Fort Dodge Animal Health, Fort Dodge, Iowa 50501 USA) is an excellent induction agent but does have recovery times that tend to be somewhat prolonged. There is no reversal agent for Tiletamine, but zolazepam can be reversed as per above.

 Opiates- primarily used as perioperative analgesics, they do produce respiratory depression in several species and should be used with cautious dosing in combination with other agents (i.e. benzodiazepines, alpha 2 agonists, and dissociatives). Investigations into oral administration of ultra-potent narcotics such as carfentanil have been reported in the literature in ursids with some success. Risk of accidental exposure to these dangerous narcotics is a risk that outweighs the potential benefits of this induction option. Accidental exposure kit with reversals/ antagonists and CPR certification are a necessity if this class is used.

 Alpha 2 agonists- Xylazine, Detomidine, Medetomidine and dexmedetomidine (Domosedan, Domitor and Dexdormitor, Pfizer Animal Health. Exton, PA 19341 USA) combinations are potent reversible sedatives that are typically used in combination with other classes of drugs (i.e. Ketamine to smooth inductions). Use caution when using this class alone as it primarily induces to the level of heavy sedation and can cause vomiting upon induction of anesthesia. This class can be antagonized by the catecholamine response of restraint and has risk of animal arousal when used alone. Dosages are included in Table 1 for xylazine, detomidine and medetomidine with dexmedetomidine being investigated and reported in the literature at half the dose/ dosage requirement. In addition to the sedation and analgesia seen with alpha 2-agonists such as medetomidine, significant effects on the cardiovascular system are also seen and need to be considered before this drug is chosen. Vasoconstriction with compensatory bradycardia may be seen. It is controversial to utilize anticholinergics such as atropine or glycopyrrolate to address these concerns. Consider ¼- ½ reversal dose if other drugs are on board as an alternative. Reversal of alpha 2 agonists can be accomplished with drugs such as yohimbine and atipamezole, or tolazoline at dosages reported in Table 1. Medetomidine + midazolam +/- butorphanol combination has been reported for a variety of carnivores; although, for prolonged procedures, supplementation with gas anesthesia or other drugs may be warranted as arousal at about 60 minutes post- induction has been reported in some species.

It is recommended to evaluate degree of sedation before approaching an animal using a long pole with either the palpebral reflex or ear twitch reflex. Generally, if the animal still appears to have these reflexes intact after 10-15 minutes post- injection, supplements may be warranted. Lateral recumbency with the neck extended is the ideal position for anesthesia. Once an animal has been anesthetized, endotracheal intubation and IV catheter placement should be considered, especially for larger carnivore species. Comparative medicine is your friends in this realm as these procedures are quite comparable to their domestic counterparts. In larger felids and ursids, head and neck extension is critical to keep the endotracheal tube from kinking and occluding the airway. Baseline monitoring should include temperature, pulse and respirations and should be re-evaluated every 5-10 minutes. Additional monitors to consider include portable peripheral pulse oximetry, end tidal CO2 monitors, electrocardiographs, and blood pressure monitors (wrist cuffs on the tails of large carnivores works well).

Analgesics: Analgesics should be routinely used whenever pain is present or anticipated. Cutaneous pain control methods such as Fentanyl patches are generally not successful because they need to be applied prior to the procedure and non-compliance. Domestic animal dosing can be used for opiates and NSAIDs. For dosing information, see Table 1.

Recovery: If the animal is a colony animal and must go back in with its group- care must be used in re-introduction, especially if animal has been out for an extended period of time or is still not fully recovered. In field conditions, the animal should not be left unattended until fully recovered and should be away from any hazards including other animals. Reversible combinations are ideal for these conditions. Consider keeping eyes and ears covered as long as possible to smooth recovery and minimize stimulation where animal might attempt flight response without presence of complete faculties.

Remote Injection Equipment

 http://www.daninjectusa.com

 http://www.pneudart.com

 http://www.telinject.com

Portable Inhalant Anesthesia Machines

 http://www.dremed.com/catalog/index.php/cPath/60

Table 1. Some Commonly Used Anesthetics and Analgesics in Carnivores^1,3-8 (NR= not reported)

Resources

1.  Fowler, M (ed.), Restraint and Handling of Wild and Domestic Animals, 1995, Iowa State University Press, Ames, IA.

2.  West, G, Heard, D, Caulkett, N. (eds.). Zoo Animal and Wildlife Immobilization and Anesthesia, 2007, Blackwell Publishing, Ames, IA.

References

1.  Caulkett. N. Bears. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 409- 416.

2.  Fowler, M. Carnivores. 1995. Restraint and handling of wild and domestic animals, Iowa State University Press, Ames, IA. 221-235.

3.  Gunkel, C, et al. Felids. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 437- 442.

4.  Hahn, N, et. al. Hyenas. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 437- 442.

5.  Kollias, G, et al. Procyonids and mustelids. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 417- 427.

6.  Larsen, S, Kreeger, T. Canids. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 395- 408.

7.  Moresco, A., Larsen, S. Viverids. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 417- 427.

8.  Shury, T. Physical restraint: Carnivores. 2007. West, Heard, D., Caulkett, N. (eds), Zoo Animal and Wildlife Immobilization and Anesthesia, Blackwell Publishing, Ames, IA, pp. 134-137.