Cerebral Vascularization and the Remaining Area Supply of the Internal Carotid Artery Derivatives of the Red Kangaroo (Osphranter rufus)

The red kangaroo (Osphranter rufus) is a member of Macropidideae superfamily. It is one of the four kangaroo species living nowadays, and it is the biggest one. It is native to Australia, where it is an abundant species living across the whole continent in stable populations. Outside its natural habit, the red kangaroo is a common species found in zoos and as patients in wildlife rehabilitation centers. Reports on kangaroo anatomy are scarce. Describing detailed anatomy is a base for establishing diagnostic and treatment protocols for different species of animals. Cardiovascular diseases and pathological changes suggestive of hypertension have been previously described in kangaroos. This creates a necessity for detailed studies on species' vascular anatomy. New reports in the field of detailed vascular anatomy can bring considerable information that complements numerous studies on the evolution or biology of individual species. In this article, we describe the arterial vascularization of the brain and nearby regions of the cranial cavity using various anatomical techniques. The vascularization of the brain is discussed and compared with different mammalian species.

FATAL GASTRIC DILATATION AND VOLVULUS IN THREE CAPTIVE JUVENILE LINNAEUS'S TWO-TOED SLOTHS (CHOLOEPUS DIDACTYLUS)

Linnaeus's two-toed sloth (Choloepus didactylus) is one of two extant neotropical species of the family Megalonychidae. Despite their being commonly kept under managed care, the digestive physiology of sloths remains poorly understood. Gastrointestinal disease has been reported as a primary or contributing cause of morbidity and mortality in captive two-toed and three-toed (Bradypus spp.) sloths. Gastric dilatation due to gas accumulation ("bloat") has been reported in sloths; however, a literature search failed to yield any published mention of gastric volvulus in any sloth species. Following an inquiry sent to the electronic mailing lists of the American Association of Zoo Veterinarians, the European Association of Zoo and Wildlife Veterinarians, and the LatinVets community, three cases of fatal gastric dilatation and volvulus (GDV) were identified in one male and two female Linnaeus's two-toed sloths from institutions in the United States, Canada, and Germany. All cases occurred in juvenile sloths <1 yr of age. Two animals were primarily hand reared, whereas one was reared primarily by its dam. Two animals were found dead with no overt premonitory signs, whereas one animal died following a 3-wk course of waxing and waning clinical signs consistent with gastric gas accumulation. In all cases, GDV was diagnosed on postmortem examination. Similar to other species, the condition is likely subsequent to a combination of host- and husbandry-related contributing factors. Further research into sloth husbandry is required in order to take an evidence-based approach to their management.

MEDETOMIDINE-KETAMINE-MIDAZOLAM VERSUS MEDETOMIDINE-KETAMINE-BUTORPHANOL FOR IMMOBILIZATION OF RED KANGAROOS (OSPHRANTER RUFUS)

The objectives of this clinical study were to compare the effectiveness and safety of medetomidine-ketamine-midazolam (MKM) versus medetomidine-ketamine-butorphanol (MKB) for immobilization of captive red kangaroos (Osphranter rufus). Twenty red kangaroos were randomly immobilized for routine treatments using intramuscular injection of MKM (0.065 ± 0.004, 2.2 ± 0.3, and 0.12 ± 0.04 mg/kg, respectively) or MKB (0.070 ± 0.015, 2.3 ± 0.5, and 0.23 ± 0.05 mg/kg, respectively) (n = 10/group). Induction, immobilization, and recovery times were recorded; vital signs monitored; and quality of induction, immobilization, and recovery scored using a single-blinded design. Oxygen was not supplemented. For reversal, atipamezole at five times the medetomidine dosage was administered intramuscularly (both groups), and flumazenil (0.020 ± 0.003 mg/kg; MKM) or naltrexone (0.23 ± 0.05 mg/kg; MKB) were administered intravenously. Induction time was significantly shorter in the MKB group versus the MKM group (7:26 ± 04:22 and 11:54 ± 04:50 minutes, respectively). Induction quality in both groups was rated "excellent" and immobilization quality was "excellent" in MKM and "very good" in MKB. Heart rate was significantly lower and hemoglobin oxygen saturation (SpO₂) was significantly higher in the MKM versus the MKB group. However, SpO₂ < 90% occurred with both protocols. Following antagonists administration, recovery time and quality were 17:40 ± 08:33 minutes and "very good" in the MKM group, and 14:28 ± 05:27 minutes and "excellent" in the MKB group, respectively. Both protocols provided smooth induction, good immobilization, and generally quick recovery. MKB is recommended for shorter induction time. Oxygen supplementation should be available with both protocols.

The large-scale capture of eastern grey kangaroos (Macropus giganteus) and red kangaroos (Osphranter rufus) and its application to a population management project

OBJECTIVE

A large-scale capture method was developed to enable sterilisation of a macropod population in western Sydney from 2005 to 2018.

METHODS

Until March 2007, free ranging eastern grey kangaroos and red kangaroos were herded into purpose-built 15 m diameter capture yards (CYs) for darting with a projectile syringe. From March 2007 onwards, animals were free-range darted in large areas without herding. Kangaroos were darted with 1.33-5.10 mg/kg tiletamine/zolazepam and 0.01-0.02 mg/kg medetomidine, ± 0.03 mg/kg acepromazine. Deaths were monitored. Population counts were performed annually.

RESULTS

There were 5825 capture events involving 3963 kangaroos. Over 85% of all captures occurred from 2005 to 2008. Of all reported deaths (n = 523), 135 were attributed to ill health. Musculoskeletal injuries incurred during capture were the main project-related cause of death (n = 116). Post capture myopathy was uncommonly diagnosed following capture (n = 19).

CONCLUSION

The herding and capture method enabled a large number of kangaroos to be mobilised and captured with low mortality rates, and the use of CYs resulted in fewer capture-related injuries and deaths than free-range capture. The drug doses and combinations used for darting were safe and effective, and the capture technique was successfully applied to a population management project.

Laparoscopic ovariectomy in eastern grey kangaroos (Macropus giganteus) and red kangaroos (Macropus rufus)

OBJECTIVE

To develop a technique for permanent sterilisation of female eastern grey kangaroos (Macropus giganteus) and red kangaroos (M. rufus) as part of a large-scale macropod management program on an enclosed 1545-ha site in western Sydney.

METHODS

Free-ranging female kangaroos (n = 1409: 1285 eastern grey kangaroos, 124 red kangaroos) were anaesthetised via remote anaesthetic drug delivery of tiletamine/zolazepam, medetomidine and acepromazine prior to inhalational anaesthesia using isoflurane-oxygen. A laparoscopic ovariectomy technique was developed using standard laparoscopic equipment to effect permanent sterilisation of the kangaroos. The technique described was also adapted for use on immature animals weighing as little as 1 kg. No direct post-surgical care was provided once the animals had recovered from the anaesthetic.

RESULTS

The procedure was simple to perform and had a very high success rate, with an overall project mortality rate of 2.13% (n = 30). Seven kangaroos (0.05% of all operated kangaroos) were euthanased as a direct result of the surgical procedure. Surgical complications were rare but included inadvertent gastrointestinal tract puncture with the trocar, intraoperative haemorrhage and subcutaneous emphysema leading to pouch eversion following surgery.

CONCLUSION

The procedure described is a rapid and effective method of permanent fertility control in macropods and carries a low mortality rate.