Immobilization of the endangered Iberian lynx with xylazine- and ketamine-hydrochloride

How Should We Help Wild Animals Cope with Climate Change? The Case of the Iberian Lynx

Climate change and related shifts in weather conditions result in massive biodiversity declines and severe animal suffering. This article explores the measures that can be taken to decrease animal suffering and prevent species from going extinct. Taking the Iberian lynx as a case study, we assess the extent to which it is beneficial for animal welfare and species conservation to do nothing or reduce other threats, provide food or shelter, relocate the species via assisted migration, or bring the population into captivity. We argue that, given the Iberian lynx's non-invasive characteristics, assisted migration may be the best way to protect the species while ensuring animal welfare and protecting wildness and other ecosystem values.

Benign juvenile idiopathic epilepsy in captive Iberian lynx (Lynx pardinus) in the ex situ conservation program (2005-2019)

Background

Benign juvenile idiopathic epilepsy has been described in humans but rarely in animals. The objectives of the study were to describe the clinical signs, clinical data, imaging findings, genetic examinations, treatment, long-term outcome and prognosis in Iberian lynx with juvenile epilepsy. Medical records, video recordings and diagnostic data from 2005 to 2019 were reviewed.

Results

Twenty lynx cubs with early onset of epileptic seizures (ES) from the conservation program were included. The average age at seizure onset was 75 days. Isolated and cluster ES were recorded. Focal ES, focal ES evolving into generalized ES with a stereotypical pattern and generalized ES were observed. All the cubs were normal between episodes, had a normal neurological examination and unremarkable investigations. Phenobarbital was used as a first line antiepileptic drug (AED). ES halted 10 days (0–34) after starting treatment in eight out of twenty cubs (40%). Treatment was discontinued in this group after a mean of 578 days and no further ES were reported (mean follow-up longer than 5 years). Eleven animals (55%) continued on AED treatment for a mean of 1306 days (70–3466). An adult-onset was observed for one lynx (5%). Polytherapy was necessary in seven lynxes (35%). The inheritance pattern observed was compatible with an autosomal recessive condition. Based on this assumption, mating between two identified carriers has been avoided since 2012, which may have contributed to the subsequent decrease in prevalence, with no further cases detected in 2018 and 2019.

Conclusions

Lynx pardinus may have an early onset self-limiting ES syndrome characteristic of benign juvenile idiopathic epilepsy. Information obtained from this study strongly suggests a genetic basis for the here presented epilepsy.

Chemical immobilisation of dhole (Cuon alpinus), Indian jackal (Canis aureus indicus) and Indian wolf (Canis lupus pallipes) with ketamine hydrochloride-xylazine hydrochloride

Maintaining wild animals in captivity often requires chemical immobilisation to achieve various diagnostic, surgical and management interventions. Four dholes, two Indian grey wolves and four Indian jackals were immobilised using ketamine–xylazine combination for either medical or management interventions. Based on the estimated body weight, canids were darted upon with 6–8 mg kg⁻¹ ketamine and 0.7–1.14 mg kg⁻¹ xylazine. Initial signs of drug effect included decreased mentation and progressive ataxia followed by recumbency. The mean ± SD of induction time was 14.25 ± 2.75 (range: 11–17 min), 11 ± 3.16 (range: 8–15 min) and 15.5 ± 3.54 (range: 13–18 min) in dhole, Indian jackal and Indian wolf, respectively. Hyperthermia was initially observed in all the jackals and dholes, whereas rectal temperature in wolves remained well within the normal range for canids. The mean duration of anaesthesia was 31 ± 8.83 (range: 23–43 min), 32.5 ± 5.32 (range: 26–39 min) and 30.5 ± 7.78 (range: 25–36 min) in dhole, Indian jackal and Indian wolf, respectively, with subsequent smooth and uneventful recovery in all the cases. The observations made during immobilisation procedures in this work suggest that chemical immobilisation of captive dhole, Indian wolf and Indian jackal with 6–8 mg kg⁻¹ ketamine and 1 mg kg⁻¹ xylazine is effective and safe for routine management and medical interventions in these species provided body temperature is closely monitored and corrected as appropriate.

Chemical Immobilization of Sloth Bears (Melursus ursinus) with Ketamine Hydrochloride and Xylazine Hydrochloride: Hematology and Serum Biochemical Values

The present study was conducted to define the physiological responses of captive sloth bears immobilized with ketamine hydrochloride and xylazine hydrochloride and to determine and compare the values of hematology and serum biochemical parameters between sexes. A total of 15 sloth bears were immobilized using combination of ketamine hydrochloride and xylazine hydrochloride drugs at the dose rate of 5.0 milligram (mg) per kg body weight and 2.0 mg per kg body weight, respectively. The use of combination of these drugs was found satisfactory for the chemical immobilization of captive sloth bears. There were no significant differences observed in induction time and recovery time and physiological parameters such as heart rate, respiratory rate, and rectal temperature between sexes. Health related parameters comprising hematological values like packed cell volume (PCV), hemoglobin (Hb), red blood cell count (RBC), erythrocyte indices, and so forth and biochemical values like total protein, blood urea nitrogen (BUN), creatinine, alkaline amino-transferase (ALT), aspartate amino-transferase (AST), and so forth were estimated in 11 (5 males and 6 females) apparently healthy bears. Comparison between sexes revealed significant difference in PCV (P < 0.05) and mean corpuscular hemoglobin concentration (MCHC) (P < 0.05). The study might help to evaluate health profiles of sloth bears for appropriate line treatment.

Determination of serum biochemical reference intervals for the Iberian lynx (Lynx pardinus)

Biochemical reference intervals were determined for 31 clinically healthy Iberian lynxes (Lynx pardinus) between 1 and 6 years of age. Thirteen of the lynxes were wild-caught and the other 18 were captive-reared animals. The samples were collected between November 2004 and December 2006. The influence of sex (males vs. females), age (juveniles vs. adults) and habitat condition (free-living vs. captive) on the biochemical analytes were evaluated. Serum albumin concentrations were significantly higher in females than in males, while creatine phosphokinase was higher in males. The levels of alkaline phosphatase and lactate dehydrogenase were higher in juvenile lynxes, while gamma glutamyl-transferase and creatinine values were higher in adults. Lynxes captured in the wild had higher concentrations of iron, calcium, alkaline phosphatase and creatinine, but lower aspartate aminotransferase and alanine aminotransferase than lynxes maintained in captivity. The results were generally comparable to commonly reported reference intervals for other lynx species, the domestic cat and other felid species.

Exposure to disease agents in the endangered Iberian lynx (Lynx pardinus)

The Iberian lynx (Lynx pardinus) is the most endangered felid species in the world. Lynx populations have decreased dramatically in size and distribution in the last four decades, thus becoming increasingly vulnerable to catastrophic events such as epizooties. From 1989 to 2000, serum samples were obtained from 48 free-ranging lynx captured in the Doñana National Park (DNP, n = 31) and mountains of Sierra Morena (SM, n = 17) in southern Spain. Samples were tested for antibodies against Toxoplasma gondii, feline herpesvirus 1 (FHV-1), feline calicivirus (FCV), feline/canine parvovirus (FPV/CPV), feline coronavirus, feline immunodeficiency virus (FIV), feline leukaemia virus and canine distemper virus (CDV) and for FeLV p27 antigen, to document baseline exposure levels. Antibodies against T. gondii were detected in 44% of lynx, with a significantly greater prevalence in DNP (61%) than in SM (12%). In DNP, prevalence was significantly higher in adult (81%) than in juvenile and sub-adult (41%) lynx, but no such difference was observed in SM. Low prevalences (≤11%) of minimally positive titres were found for FHV-1, FCV and FPV/CPV. This, combined with the lack of evidence for exposure to CDV, FIV and FeLV, suggests that these lynx populations are naïve and might be vulnerable to a disease outbreak in the future. Because of the reduced size of lynx populations, the documented low level of genetic variation (particularly in the DNP population) coupled with the recently documented state of immune depletion in a majority of necropsied lynx, it is important to better understand the threat and potential impact that disease agents might pose for the conservation of this endangered species. Future surveillance programs must include possible disease reservoir hosts such as domestic cats and dogs and other wild carnivores.

Epidemiology of Ancylostoma spp. in the endangered Iberian lynx (Lynx pardinus) in the Doñana National Park, south-west Spain

The epidemiology of Ancylostoma spp. was studied in the endangered Iberian lynx (Lynx pardinus) in the Doñana National Park, south-west Spain. Faecal samples were collected throughout a complete annual cycle (August 1997 to September 1998). The overall egg prevalence of Ancylostoma spp. was 57.8%. The pattern of abundance of Ancylostoma spp. eggs in faeces was overdispersed. Juvenile lynx demonstrated a statistically higher prevalence and abundance of Ancylostoma spp. than in adults. These levels of egg output (maximum 21195 epg), as previously reported in free ranging large felid cubs, could be close to disease involvement. The potential pathogenicity of hookworms and the influence of individual and ecological factors on hookworm transmission in the Iberian lynx from the Doñana National Park population are discussed.

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.

Xylazine impairs the anticonvulsant activity of conventional antiepileptic drugs in mice

In this study the influence of xylazine upon the threshold of electrically-induced convulsions and the anticonvulsant action of diazepam, phenobarbital and phenytoin was studied in mice. All drugs were given as solutions intraperitoneally (i.p.). Xylazine did not alter seizure threshold at any of the doses tested (range 0-6 mg/kg i.p.). However, when combined with seizure-increasing doses of phenobarbital and phenytoin, xylazine at a dose of 2 mg/kg significantly (P < 0.05) reduced the ability of these anticonvulsants to increase seizure threshold. Xylazine also reduced the anticonvulsant effect of diazepam, though insignificantly. Our data indicate that xylazine should be contraindicated in animals on the anticonvulsant medication.