Field System for Isoflurane Anesthesia of Multiple Species of Mesopredators

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1 University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Papers in Natural Resources Natural Resources, School of 2009 Field System for Isoflure Anesthesia of Multiple Species of Mesopredars Larkin A. Powell University of Nebraska-Lincoln, lpowell3@unl.edu Follow this additional works at: Powell, Larkin A., "Field System for Isoflure Anesthesia of Multiple Species of Mesopredars" (2009). Papers in Natural Resources This Article is brought you for free open access by the Natural Resources, School of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Papers in Natural Resources by authorized administrar of DigitalCommons@University of Nebraska - Lincoln.

2 Am. Midi. Nat. 161: A Field System for Isoflure Anesthesia of Multiple Species of Mesopredars Abstract.?Inhaled isoflure is one of my chemical immobilizing agents available for field esthesia of wildlife. We examined the use of inhaled isoflure for field immobilization of mesopredars. Five of mammals esthetized in a wetl complex in south-central Nebraska with isoflure; we developed induction chamber use with a portable esthesia machine provide esthesia at the capture location. Sixteen raccoons (Procyon lor), 20 striped skunks (Mephitis mephitis), 4 Virginia opossums (Didelphis virginia), 2 Americ badgers (Taxidea taxus) 1 mink (Mustela vison) immobilized; we radio-marked 11 raccoons 9 skunks. Induction was smooth uneventful for all immobilized. Me induction times for raccoons skunks 10.7 min (SD 1.1) 11.0 min (SD 2.4) respectively. Me hling times (post induction) 7.1 min (SD 3.9) for raccoons 7.3 min (SD 4.8) for skunks. All imals, with the exception of opossums, fully recovered within 15 min (raccoon me recovery: 11.1 min, SD 3.5; skunk me recovery: 10.9 min, SD 3.7). Recovery times for radio-collared imals uncollared imals did not differ, individuals with longer hling times did not require longer recovery times. Although isoflure requires more equipment th injectable esthesia methods, its short recovery time wide safety margins deem it practical for use in a variety of field applications. Introduction Immobilizing agents for field esthesia of wildlife are available in a variety of combinations, each varying in effectiveness relative, body weight, specific combinations dosages (Seal Kreeger, 1987; Mathews et al, 2002). Acceptable esthesics yield imal completely unconscious, unable perceive pain provide for a complete rapid recovery (Osofsky Hirsch, 2000). Common injectable esthetic agents used immobilize mesopredars in the field include ketamine (often combined with xylazine, acepromazine or medemidine), telazol, fentyl-droperidol phencyclidine penbarbital sodium (Kreeger, 2007; reviewed by Kocer, 2004). Dosages of injectable immobilizing agents are body weight dependent few serious side effects have been reported in the preceding studies. Induction times reported rapid (usually <5 min) for these drugs but recovery times prolonged in my cases ( h). Inhalation esthetics have been used in very few field settings (Feldm Self, 1971; Taulm Williamson, 1993; Lariviere Messier, 1996?, 1996&), limited mainly young imals or small enough be mually restrained or enclosed in a bag or box (Seal Kreeger, 1987). However, inhalation esthetics offer good control over the depth duration of esthesia they follow the dose-response concept (i.e., effect increases as the dose increases; Seal Kreeger, 1987; Kreeger et al, 1998). Isoflure inhaled esthesia is commonly used in hum veterinary medicine, has recently become suitable for field use with the advent of a portable vaporizer. Isoflure is one of the least xic inhalation esthetics available day (B?lt, 1995), providing smooth induction recovery for esthetized imals (Seal Kreeger, 1987). Isoflure does not require mixing drugs for induction or reversal agents. Because needles are not used, potential hum contact with the drug is greatly reduced. Not all injectable agents or combinations are completely reversible my are associated with prolonged recovery times (Mathews et al, 2002). For example, Kreeger et al (1998) reported that black-footed ferrets appeared more physiologically normal under isoflure th under injected medemidine ketamine. Isoflure has been successfully used in field studies esthetize muskrats (Ondatra zibethicus; B?lt, 1995), beaver (Casr cadensis; Breck Gaynor, 2003), Siberi polecats (Mustela eversmni; Gaynor et al, 1997), Steller's sea lions (Eumepias jubatus, adults pups; Heath et al, 1996; Heath et al, 1997) black-footed ferrets (M. nigripes; Kreeger et al, 1998). Despite the benefits of using isoflure, it is not commonly used esthetize mesopredars (Lewis, 2004) because it is difficult use induction chamber in the field. 406

3 2009 Notes Discussion 407 In the present, isoflure was used on multiple in short-duration procedures in the field because of its simplicity, rapid induction recovery, minimal side effects (Seal Kreeger, 1987). Previous studies have not examined the effects of isoflure esthesia on recovery times. Our is the first document the concurrent use of isoflure on five mesopredar. The objectives of our (1) a develop useful chamber for the use of isoflure gas as a field esthesia for a suite of mesopredars (2) determine the effect of esthetized hling time on imal recovery time. Methods area target Our research was conducted as part of a mesopredar in the Rainwater Basin wetls of south-central Nebraska (Kocer, 2004). We imals in wire box traps for a 4-5 d period twice between May August each year. Raccoons (Procyon lor) striped skunks (Mephitis mephitis) the primary target of our based on abundce, ease of capture ability carry a radio trsmitter. We radio-marked a subsample of raccoons skunks using 30-g radio collars (model MI-2, Holohil Systems Ltd. Corp, Ontario, Cada). We also Virginia opossums (Didelphis virginia) Americ badgers (Taxidea taxus), which also radio-collared when possible. We one mink (Mustela vison). FIELD ANESTHESIA METHODS We esthetized imals with isoflure (MWI Veterinary Supply Co., Nampa, ID) using a portable esthesia machine, designed by Dr. R. B. Heath, DVM (Seven Seven Anesthesia, Fort Collins, CO; Fig. 1). The machine was fully portable (weight: 11.5 kg), easily constructed collapsed in minutes. The unit consisted of a vaporizer connected a Baines non-rebreathing circuit with side port bag valve. Non-rebreathing systems are light-weight, offer reduced breathing resistce, are useful for smaller imals or imals with unknown respirary problems that may not be immediately apparent in the field (Lerche et al, 2000). Use of a precision-calibrated vaporizer allowed us utilize the control advtages offered by inhalation esthetics (Seal Kreeger, 1987). The entire machine sat on a telescoping tripod that adapted uneven terrain. The vaporizer was connected a portable medical oxygen cylinder (size E) using stard circuitry. Previous studies used clear plastic (Gaynor et al, 1997), Plexiglas? (Kreeger et al, 1998) or wooden (Baiser Kinsey, 1962) boxes, as well as trsparent polyethylene bags (Mathews et al, 2002) as induction chambers for inhalation esthesia. However, these chambers inadequate for our multi in a temperate grassl/wetl lscape that afforded little shade. The in this a required chamber that could accommodate a wide rge of body sizes provide shade from the sun induction. We found that our traps punctured heavy plastic bags, making them inefficient. Thus, we constructed improved induction chamber by modifying opaque, plastic outdoor c garbage (dimensions: diameter, p 48 cm base 38 cm; height 78 cm). We chose use a tall cylindrical chamber make it difficult for the imal escape as it was trsferred from the trap the chamber. The opaque color of the chamber kept the imal shaded from the sun induction, the darkened chamber helped quiet the imal, a promoting smooth induction (Mathews et al, 2002). We constructed a plunger make the chamber's volume adjustable, seal the imal in the chamber minimize the volume be filled with the isoflure/oxygen mixture needed esthetize the imal. The plunger (dimensions: p diameter: 46 cm, base diameter: 35 cm, height: 14 cm) was constructed from a plastic tub (#H11501, Wal-Mart Sres, Inc., Bennville, AR) cut fit the opening of the garbage c. A 64-cm2 observation window was cut in the botm of the tub, fitted with Plexiglas? reinforced with so plywood that we could observe the imal while in the chamber (Fig. 2). The p, outer edge of the plunger was fitted with a bicycle inner tube create airtight seal, which prevented isoflure from escaping the chamber. We attached hles the plunger base, we could depress the plunger a level just above the imal. To connect the chamber the esthesia machine, we fitted a short rubber pipe in a hole cut through the floor of the plunger in which a hose was fitted administer the esthesia (Fig. 2).

4 408 The Americ Midl Naturalist 161(2) Fig. 1.?Field-suitable isoflure gas esthesia vaporizer used immobilize mesopredars in the field (Rainwater Basin region, south-central Nebraska). Designed by Dr. R. B. Heath, DVM (Seven Seven Anesthesia, Fort Collins, CO) We trsferred imals from a live trap in the induction chamber; we used a heavy cloth bag move the imal from the trap the chamber. Trsfers easily accomplished occurred without incident. Animals (e.g., mink) in smaller traps could be placed directiy in the indication chamber with the trap. Once the imal was inside the chamber, we depressed the plunger a depth of approximately 50 cm from the p of the chamber, just above the imal. Because isoflure esthesia dose is not body-weight dependent, we did not need weigh imals before induction. We administered a concentration of 5% isoflure in 3 L of oxygen per minute. After approximately 10 min, we checked the imal evaluate the degree of immobilization, more time was allotted when necessary. During induction, we used the plunger window watch for laryngospasm, coughing, breath holding agitation; we monired the chamber for increased secretions when we removed the imal. Complete immobilization was determined by unresponsiveness stimuli, such as movement of the induction chamber. Induction time was defined as the period which the inhalt gas was turned on until the imal was removed from the chamber. Upon complete immobilization, we removed the imal from the chamber, decreased the concentration of isoflure 3% in 3 L of oxygen per minute, placed a small, stard nose cone fitted with a rubber ring over the imal's muzzle maintain immobilization hling. The imal was on a placed foam mat hling reduce heat loss (Mathews et al, 2002). We defined hling time as the amount of time the imal was out of the chamber, with a nose cone securely over its nose mouth. While unconscious, the imal was sexed, weighed ear tagged, we marked a subsample with radio-collars. We continued use esthesia until these procedures complete, then placed the imal in a trsport kennel recover after the esthesia was turned off, we allowed the imal recover. Complete recovery was determined by alertness, ability st upright ability move in the kennel without stumbling. Recovery time was defined as the time from removal of the nose cone until release. Each imal was released at its capture site after it was fully recovered, all equipment was thoroughly disinfected with bleach wipes between individuals.

5 2009 Notes Discussion 409 Fig. 2.?Isoflure gas esthesia chamber shown with plunger depressed. Labels are: (A) the hose that administered the esthesia (see Fig. 1, left) (B) the Plexiglas window used observe the imal induction We located radio-marked imals the night after marking evaluate movement survival following esthesia induction. The University of Nebraska-Lincoln's Institutional Animal Care Use Committee (IACUC) our approved research methods prior our field work (University of Nebraska Lincoln IACUC Permit # ). STATISTICAL ANALYSIS We focused our statistical alyses on raccoons (n 16) skunks (n 20), which had the largest sample size, although we used isoflure esthesia on all mesopredars. During esthesia, we recorded the time at four points: (1) when the esthesia gas was initially turned on, (2) when immobilization was achieved the level of isoflure/oxygen gas was reduced, (3) when the nose cone was removed (4) when the imal was released. We used a two-sample t-test compare induction, hling recovery times between raccoons skunks; induction times for badgers opossums had smaller sample sizes, we used me induction times associated SD for comparisons. Our was working hypothesis that isoflure would work equally well for our target ; we tested that hypothesis by looking for statistically similar induction recovery times. Species specific excitability levels could also cause differences in induction. Some imals in our sample radio-marked with a collar. Because of the time needed attach the collar, radio-marked individuals spent more time under esthesia (hling time) th individuals that did not receive radio collars. We used a linear times resulted in longer recovery times. Results regression alysis determine if longer hling During , we immobilized 16 raccoons (2002: 10; 2003: 6), 20 skunks (2002: 10; 2003: 10), 4 opossums (2002: 2; 2003: 2) 2 badgers (2003). In 2002, we also immobilized one mink. We radio-marked 11 of 16 raccoons 9 of 20 skunks. Each imal was only immobilized once our as we did not recapture y imals. Radio telemetry indicated that all radio-marked imals survived the first week following capture esthesia.

6 410 The Americ Midl Naturalist 161(2) Table 1.?Me times, in min (SD), required for immobilization, hling various using inhaled isoflure esthesia recovery of five Hling Recovery n Species Induction Collareda Uncollared Collareda Uncollared Raccoon (1.1) 8.8 (3.4) 3.2 (1.1) 10.7 (4.0) 11.8 (2.5) Striped Americ Virginia Skunk (2.4) 11.1(4.2) 4.18(2.4) 10.2(5.1) 11.5(2.1) Badger (2.1) 20b 14b 10b 10b Opossum (8.1) 6b 3.7(4.7) 14b 19.7(11.2) 1 Mink 10b 10b 5b a Radio-collared 1 badger b No SD; n 1 sample sizes: 11 of 16 raccoons, 9 of 20 skunks radio-collared; 3 of 4 opossum Induction was smooth uneventful for all immobilized. Me induction times did not differ between raccoons skunks (Table 1;? , P? 0.33). Induction time for the two badgers was higher th for raccoons skunks, possibly due their excited states after capture. The four opossums had variable induction times (Table 1 ). We did not observe laryngospasm, coughing, breath holding, increase in secretions or agitation for y induction. Me hling times did not differ between raccoons skunks (? , P 0.44). There was a significt difference in hling times for radio-collared versus uncollared individuals (Table 1; %0 5.91, P < 0.001). Me hling time for collared individuals was 9.9 min (SD 3.9) uncollared individuals was 3.9 min (SD 2.1). All imals, with the exception of opossums, fully recovered within 15 min (Table 1). Recovery time for collared individuals (me: 10.5 min, SD 4.39) did not differ from uncollared individuals (me: 11.6 min, SD 2.13; fa 0.95, P 0.17); this pattern held for raccoons skunks (Table 1). Longer hling times did not require longer recovery times (slope?0.12, if 0.02, P 0.41). Discussion We did not observe y adverse effects or deaths esthesia or recovery as a result of isoflure immobilization. We normally administered isoflure for 10 min before disturbce ensure immobilization before hling, the 10-minute induction time worked well for our 's objectives. B?lt (1995) reported extremely prolonged induction time using isoflure in muskrats (18-24 min for adults), which may be due the fact that isoflure soaked cotn ball was used rather th a vaporizer oxygen. Higher levels of oxygen help promote rapid induction (Dr. C. Morg D.V.M., pers. comm.). Excitement levels also contribute a prolonged or unsuccessful immobilization; a calmer imal will a undergo safer smoother induction (Seal Kreeger, 1987). We observed no differences in recovery among the target of our. In three instces, the imal became very active after only 2-3 min following the conclusion of isoflure esthesia. Although induction is more rapid using injectable esthetics, recovery appears be considerably shorter using inhaled isoflure. Opossum recovery time (18.3 min, SD 9.6) may have been artificially inflated, as opossums, by their nature, feign death as a defense mechism. In one instce, we observed individual for over 30 min after esthesia was removed; this long "recovery" inflated the average recovery time for opossums. Biologists must consider several characteristics of esthesia systems as they pl field experiments. Portable esthesia systems are relatively expensive in comparison injectable systems. In 1998, Kreeger et al (1998) reported that their portable gas esthesia system cost approximately $7,000. However, the system that we used cost significtly less ($1,400), suggesting that this method is more becoming affordable. Isoflure is inexpensive ($60 per 250 ml) easy hle. It comes in a liquid form is sred at room temperature. Although isoflure esthesia mechisms are bulkier th injectible esthesia equipment, we operated efficiently from a pick-up truck at roadside wetls. Heath et al (1996) used backpacks trsport this esthetic equipment when imals

7 2009 Notes Discussion 411 trapped at a remote location; we considered the use of all-terrain vehicles trsport equipment in our. Our modified esthesia chamber allowed us esthetize mesopredars with a variety of body sizes. The use of isoflure system as sole esthesia is best suited for small medium sized imals. Because of complications of delivery induction, larger mammals will likely need be immobilized using injectable esthetic; isoflure c be used prolong esthesia as Heath et al (1996) reported in Steller's sea lions. In conclusion, isoflure inhaled esthesia produced smooth uneventful induction recovery in the mesopredars considered in this. The additional time under esthesia required radio-mark imals did not affect recovery times. Our suggests that isoflure c be a suitable esthesia for mesopredars in my field situations. Isoflure requires more equipment th injectables, but its ease of use wide safety margins make it practical for use in a variety of field applications. Acknowledgments.?We would like acknowledge J. Curinga, K Neiderklein, M. Post v der Burg, Z. Cunningham M. Metz for their help in the field. Dr. K Amass D.V.M, Dr. C. Morg D.V.M. Dr. B. Heath D.V.M. invaluable in the development implementation of this form of field esthesia. R. Bischof (Nebraska Game Parks Commission) J. Curinga designed the chamber used in this. The Nebraska Game Parks Commission provided funding, research vehicles technical support the University Research Council (UNL) Laym Foundation provided funding. The US Fish Wildlife Service provided housing as well as technical support. C. Kocer was on supported assisttship from the School of Natural Resources, UNL. This is Journal Series No from the University of Nebraska Agricultural Research Division, Lincoln, Nebraska Literature Cited Balser, D. S. C. Kinsey A variable size 43:552. esthetizing chamber for imal hling./. B?lt, J. L Isoflure as inhalation esthetic for muskrats (Ondatra zibethicus). J. Wild. Dis., 31: Breck, S. W. J. S. Gaynor Comparison Wild. Dis., 39: Mass., of isoflure sevoflure for esthesia in beaver./. Feldm, D. B. J. L. Self Sedation esthesia of the Virginia opossum, Didelphis virginia. Lab. Anim. Sei, 21: Gaynor, J. S., J. Wimsatt, C. Mallinckrodt D. Biggins A isoflure for short-term esthesia in 28: comparison of sevoflure polecats (Mustela eversmni). J. Zoo Wild. Med., Heath, R. B., C. Calkins, D. McAllister, W. Taylor T. Spraker Telazol isoflure field esthesia in free-rging Steller's sea lions (Eumepias jubatus). J. Zoo Wild. Med., 27: , R. DeLong, V.Jameson, D. Bradley T. Spraker Isoflure esthesia in free rging sea lion pups./. Wild. Dis., 33: Kocer, C. J Mesopredar movement, abundce, habitat selection in the Rainwater Basins of Nebraska. M.S. thesis, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. Kreeger, T. J Hbook of Wildlife Chemical Immobilization. International Wildlife Veterinary Services, Laramie, Wyoming. -, A. Vargas, G. E. Plumb E. T. Thorne Ketamine-medemidine or isoflure immobilization of black-footed ferrets./ Wild. M., 62: Lariviere, S. F. Messier. 1996a. Field esthesia of striped skunks, Mephitis mephitis, using C. Field Nat, 110: b. Immobilization of striped Lerche, P., W. M. Muir III R. M. Bednarski Nonrebreathing practice./ Am. Vet. Med. Assoc, 217: Lewis, J. C. M Field use of isoflure air esthetic equipment 35: halothe. skunks with telazol. Wild. Soc. Bull, 24: esthetic systems in wildlife./ in small imal Zoo Wild. Med.,

8 412 The Americ Midl Naturalist 161(2) Mathews, F., P. Honess S. Wolfensohn Use of inhalation aesthesia for wild mammals in the field. Vet. Rec, 150: Osofsky, S. A. K J. Hirsch Chemical restraint of endgered purposes: a practical primer. Oryx, 34: mammals for conservation Seal, U. S. T. J. Kreeger Chemical immobilization of furbearers, p In: Novak, M., Baker, J. A., Obbard, M. E. Malloch, B. (eds.). Wild furbearer magement conserva tion in North America. Ontario Trappers Association, Ontario, Cada. Taulm, J. F. J. H. Williamson A simple apparatus technique for esthetizing raccoons. Am. Mid. Nat, 129: CHRISTINA University J. KOCER1 LARKIN A. POWELL2, 419 Hardin Hall, School of Natural Resources, of Nebraska-Lincoln, Lincoln, Submitted 10 Ocber 2007; accepted 23 June Present address: CT DEP Wildlife Division, Sessions Woods W.M.A., PO Box 1550, Burlingn, Connecticut Corresponding author: lpowell3@unl.edu; Telephone: ; FAX: