Repeated anaesthesia with isoflurane and xylazine/levomethadone/fenpipramide premedication in female Beagle dogs: Influence on general health and wellbeing

Abstract

SummaryBeagle dogs continue to be used in experimental studies and preclinical and clinical trials, many of which address the usage of anaesthesia. In order to reduce the number of animals, researchers tend to conduct several experiments on a single animal. The question arises, however, as to whether or not this frequent usage involves more than simply additional stress and discomfort for the individual animal. Within the framework of an existing study involving six female Beagle dogs, we investigated the effects of repeated (5) isoflurane anaesthesia with xylazine/levomethadone/fenpipramide premedication carried out at short intervals (2 weeks) and compared these with the effects of two treatments intermitted by a longer resting period (8 weeks). To verify our hypothesis that frequent anaesthesia affects the dog's wellbeing more than the occasional anaesthesia, the following parameters were measured at regular intervals: body weight, body temperature, respiratory rate, blood pressure, reflexes and heart rate, both at rest and during a treadmill exercise. In addition, recovery behaviour subsequent to anaesthesia was monitored for one hour. Our observations indicate that the anaesthetic effects are most prominent 24 h after the anaesthetic treatment. However, crossover analysis of our data cannot show that there is no statistical difference of whether dogs were anaesthetized occasionally or frequently. In our study, it appears that frequent anaesthesia within a two-week period did not affect the wellbeing and general health of Beagle dogs in a super-additive manner and that a minimum of two-week testing-free period is sufficient to ensure complete recovery from the unwanted effects induced by anaesthesia.Keywords Repeated anaesthesia; isoflurane; premedication; Beagle dogs; animal welfare Beagle dogs continue to be used as laboratory animals in the development of new drugs or diagnostics, as well as for preclinical and clinical research. Complex questions and stressful or painful procedures often make it necessary to perform experiments under anaesthesia. In order to reduce the number of animals, researchers commonly conduct more than one experiment on the same animal. With regard to animal welfare, however, it needs to be ensured that the stress and discomfort for the single animal is not more than additive. To date, guidelines for anaesthesia in laboratory animals do not address the re-application of anaesthetics,

Chemical Immobilization of Raccoons (Procyon Lotor) With Ketamine-Medetomidine Mixture and Reversal With Atipamezole

“…Frequently, animals must be anesthetized more than once to change telemetry collars, download data, or measure growth. While the effects of repeated immobilization on the efficacy of anesthesia have often been studied in laboratory animals such as rats (Rattus norvegicus; Fassoulaki et al, 1994;Hedenqvist et al, 2000) or dogs (Bert et al, 2008), they have rarely been assessed in wild species (Field et al, 2002;Wheatley et al, 2006). While there is no obvious reason to expect that drug effect would be different for captive versus wild animals of the same species, it is possible that the effect of repeated immobilization on the efficacy of anesthesia may be undetectable in the wild, given that the number of repeated immobilizations for wild animals is typically lower than for captive animals.…”