Anaesthesia for Castration of Piglets: Comparison Between Intranasal and Intramuscular Application of Ketamine, Climazolam and Azaperone
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Originalarbeiten Anaesthesia for castration of piglets: Comparison between intranasal and intramuscular application of ketamine, climazolam and azaperone S. M. Axiak1, N. Jäggin1, S. Wenger1, M. G. Doherr2, U. Schatzmann1 1Division of Anaesthesiology and 2Division of Clinical Veterinary Research, Department of Clinical Veterinary Medicine, University of Bern Summary Kurznarkose zur Kastration von neugeborenen Ferkeln: Vergleich zwischen intranasaler und intramuskulärer Applikation von Ketamin, Climazolam und Azaperon The aim of this study was to compare the effect of Ziel dieser Studie war es, eine Kombination aus an anaesthetic combination given either intramus- Ketamin, Azaperon and Climazolam intranasal oder cularly (IM) or intranasally (IN) for castration of intramuskulär Kastrationsferkeln zur Narkoseein- piglets. Forty piglets aged 4 to 7 days were ran- leitung zu verabreichen und ihre Wirkung verglei- domly assigned to receive a mixture of ketamine 15 chen. 40 Ferkel im Alter zwischen 4–7 Tagen er- mg kg-1, climazolam 1.5 mg kg-1 and azaperone hielten 15 mg/kg KGW Ketamine, 1.5 mg/kg 1.0 mg kg-1, IN or IM, 10 minutes prior to castra- KGW Climazolam und 1 mg/kg KGW Azaperon tion. Physiological parameters were measured. Cas- intranasal (IN) oder intramuskulär (IM) zehn Mi- tration was videotaped for evaluation by 3 inde- nuten vor der Kastration. Physiologische Parameter pendent observers using a scoring system. Reaction wurden aufgezeichnet. and vocalization to the skin incision and cutting of Die Kastration wurde gefilmt und von drei unab- spermatic cord was evaluated and scored (0 = no hängigen Beobachtern mittels einem Punktesys- reaction, 16 = strong reaction). The IN group had tem (Kastrationsscore) beurteilt, wobei bei den a significantly higher (P < 0.01) castration score, Hautschnitten und der Durchtrennung der Samen- compared to the IM group. There was an associa- stränge jeweils Lautäusserung und Abwehrbewe- tion between castration score and room tempera- gung protokolliert wurde (0 = keine Reaktion, 16 ture in the IN group (with temperatures below 18 = starke Reaktion). Die Gruppe IN verzeichnete ºC associated with a higher castration scores (P < signifikant höhere Kastrationsscores als die IM 0.001). Heart rate was significantly higher 10 min- Gruppe (P < 0.01). Zwischen dem Kastrations- utes after castration in the IN group (P < 0.05). score und der Raumtemperatur war eine signifi- Respiratory rate was significantly higher in the IM kante Korrelation (bei Raumtemperatur <18°C group at time points -5, -1, 10, 20 and 30 (P < höhere Kastrationsscores) in der Gruppe IN. Die 0.05). The IN group was walking significantly (P < Herzfrequenz war signifikant höher in der Gruppe 0.0001) faster than the IM group. In conclusion, IM 10 Minuten nach der Kastration (P < 0.05) und this combination provides effective anaesthesia for die Atemfrequenz war zu den Zeitpunkten -5, -1, routine castration of newborn piglets when admin- 10, 20 und 30 signifikant höher in der IN Gruppe istered IM. IN administration provided shorter re- (P < 0.05). Die Aufwachphase war kürzer in der IN covery times but had significantly higher castration Gruppe (P < 0.0001). Die Kombination erzeugt scores. eine gute Anästhesie zur Ferkelkastration bei IM Verabreichung, wogegen die IN Gruppe kürzere Aufwachphasen aufwies, aber auch signifikant hö- here Kastrationsscores. Keywords: anaesthesia, castration, intramuscular, intranasal, Schlüsselwörter: Anästhesie, Kastration, intramuskulär, in- piglets tranasal, Ferkel Introduction Anaesthesia and analgesia for piglet castration is an an- according to Swiss law by 2009. The technique used imal welfare imperative and is currently required by should result in significant reduction or elimination of law in Norway and pain elimination will be necessary pain and stress for the piglets and should also be short Schweiz.Arch.Tierheilk. S. M. Axiak et al., Band 149, Heft 9, September 2007, 395–402395 ©2007 by Verlag Hans Huber, Hogrefe AG, Bern DOI 12.1024/0036-7281.149.09.395 Anaesthesia for castration of piglets acting, economical, ecologic, residue free, easy to use and azaperone 1.0 mg kg-1 were administered in com- and have a large therapeutic range. Several investiga- bination either intramuscularly (IM) or intranasally tions have been undertaken to find an ideal method. (IN) prior to the castration of the piglets. Just prior to Intramuscular ketamine and azaperone is effective but the experiment, the male piglets were sorted and prolonged recovery remains a problem (Kmiec, 2005). weighed unfasted. Pairs assigned were of the same lit- Local anaesthetic techniques are performed routinely ter and had less than 10% difference in body weight. in Norway since 2002, but do not completely block Each pair received anaesthesia on the same day, se- the nociceptive response (Haga and Ranheim, 2005). quentially. The first member of each pair was ran- Inhaled carbon dioxide provides reliable unconscious- domly assigned by a computer generated random ness, but unwanted side effects including hyperventi- number chart to receive either the IM or IN admin- lation, agitation and gasping make this technique un- istration route, while the second member of each pair acceptable (Kohler et al., 1998). Isoflurane, via a special received the other. double mask to reduce pollution of the environment and exposure to the staff, has been shown to be a fast, Anaesthesia safe and practical method (Walker et al., 2004). How- ever, handling, equipment costs and exposure con- Ketamine (Ketamin-HCl-Lösung 173 mg ml-1; Dr. E. cerns have to date limited its acceptance. Intranasal de- Graeub AG, Bern, Switzerland), climazolam (Climazo- livery systems are widely used today in human lam-Lösung 30 mg ml-1; Dr. E. Graeub AG, Bern, paediatric medicine to deliver medication in a pain- Switzerland) and azaperone (Stresnil® 40 mg ml; and stress-free manner. Intranasal ketamine and mida- Janssen Pharmaceutica, Beerse, Belgium) were com- zolam, in combination, have been used successfully for bined in saline to give a final concentration that yielded sedation of children (Louon and Reddy, 1994). An in- ketamine 15 mg kg-1, climazolam 1.5 mg kg-1 and aza- tranasal system would be “needle-less” making it more perone 1 mg kg-1 when dosed at 0.2 ml kg-1. The drugs desirable for on the farm use, as needle injury to both were mixed less than 12 hours prior to the start of the administrator and piglet can be avoided. experiments and stored at room temperature. The objectives of this study were 1) to compare the Administration of drugs commenced 10 minutes prior use of intranasal versus intramuscular administration to castration. IM administration was performed with a techniques and 2) evaluate cardiovascular effects, de- 1 ml syringe (Injekt – F®; Braun, Melsungen, Ger- gree of nociception, body temperature change and re- many) and a 0.6 × 25 mm needle (Sterican®; Braun, covery time when ketamine, climazolam and azaper- Melsungen, Germany) into the right neck muscle. A one are used in combination for castration of four to human nasal spray device, which dispensed 0.1 ml per seven day old piglets. spray, (AccuPump®, Saint-Gobain Calmar GmbH, Hemer, Germany) was used for IN administration into both nostrils. For administration, the piglets were held Animals, Material and Methods in a sternal position by the investigator with the head fixed by hand at a 45° angle. Post-administration piglets were placed into a heated straw box for obser- Animals vation. Five minutes after administration, piglets were All experiments were performed at the same commer- assessed for relaxation and recumbency. If recumbency cial Bio-Suisse organic swine facility over a 6-month was not achieved by 10 minutes after administration, period from July 2005 to January 2006. Forty purebred the animals were redosed with half of the original vol- Large White male piglets, aged 4 to 7 days, from 10 dif- ume and left undisturbed for 10 more minutes. Num- ferent litters were included in the study. Numbers are ber of animals requiring redosing was recorded. presented as medians with upper and lower 95% con- fidence intervals (CI). The median body weight of all Castration animals was 2.24 (2.1; 2.65) kg and the median age was 5 (5; 6) days. All animals were deemed healthy based on Castration was performed 10 minutes after the last ad- clinical examination, had normal testicular anatomy ministration of anaesthetic agents by the same inves- and no concurrent treatments. The Committee for An- tigator. Animals were placed in dorsal recumbency imal Experimentation of the Kanton Bern of Switzer- and the hind legs were fixed cranially with a velcro land approved the study. strap. The electrocardiogram was monitored through- out the procedure using a standard base-apex lead configuration (Datex S5®, Datex-Ohmeda, Finland). Experimental Design The scrotom was washed with a dilute chlorhexadine A randomized and blinded experimental study de- scrub (Lifoscrub®, B-Braun-Medical AG, Emmen- sign, using matched pairs for litter and weight, was brücke, Switzerland) and the castration was per- used. Ketamine 15 mg kg-1, climazolam 1.5 mg kg-1 formed with a scalpel blade (Packagon #10 sterile sin- S. M. Axiak et al., Band 149, Heft 9, September 2007, 395–402396 Schweiz.Arch.Tierheilk. ©2007 by Verlag Hans Huber, Hogrefe AG, Bern Anaesthesia for castration of piglets gle use scalpel, Lance Paragon LTD, Sheffield, Eng- Recovery land). A small skin incision was made in the scrotum Sarmazenil (Sarmasol® 1 mg ml-1, Dr. E. Gräub AG, directly over each testicle. Pressure was applied to each Bern, Switzerland) at a dose of 0.2 mg kg-1 was ad- testicle, until it emerged from the incision. The testi- ministered, using the same route as for the prior cle was then gently pulled from the incision and the agents, 30 minutes after castration for antagonization spermatic cord and vessels were cut. The entire castra- of climazolam. Time to walking from drug adminis- tion was recorded on video for later castration scor- tration was recorded when the piglets were able to ing.