Cardiopulmonary Parameters and Arterial Blood Gases During Etorphine-Medetomidine-Midazolam Immobilization in Free-Ranging Black Rhinoceroses (Diceros bicornis) Undergoing Electro-Ejaculation—A Preliminary Study

Conservation management interventions for the critically endangered black rhinoceros (Diceros bicornis) require immobilization, which offer opportunities for semen collection and cryopreservation to establish genetic reservoirs. In free-ranging rhinoceroses, a combination of the potent opioid etorphine and the tranquilizer azaperone is routinely used for chemical immobilization but is associated with muscle rigidity and severe cardiopulmonary changes. Additionally, azaperone inhibits semen emission. Seven free-ranging, male, sexually mature black rhinoceroses were immobilized with an alternative protocol consisting of 4.5 mg etorphine, 5 mg medetomidine, 50 mg midazolam and 2,500 IU hyaluronidase delivered remotely by darting from a helicopter. During the immobilization, electro-ejaculation was performed with a portable electro-ejaculator, and a species-specific rectal probe. Animals were observed for muscle tremors. Longitudinal changes in respiratory rate, heart rate and peripheral oxyhemoglobin saturation, measured at 5 min intervals, were assessed using a general mixed model. Non-invasive oscillometric blood pressure and arterial blood gas variables were measured at first handling and before reversal and compared using the Wilcoxon rank sum test. All animals were successfully immobilized, showed no muscle tremors, presented with normal heart rates and lactate concentration (<5 mmol/L), recovered uneventfully, but experienced acidemia, hypoxemia and hypercapnia. Induction time and total time in recumbency were 4.2 ± 0.41 and 38.4 ± 6.9 min, respectively. Electro-stimulation commenced after 11.7 ± 3.98 min and completed after 24.3 ± 6.65 min. Semen-rich fractions were successfully collected from six animals. Our observations indicate that etorphine-medetomidine-midazolam provides a promising immobilization protocol for free-ranging black rhinoceroses, that allows for successful electro-ejaculation.

Genetic Management of Wild and Translocated Black Rhinoceros in South Africa’s KwaZulu-Natal Region

<p>The African black rhinoceros (Diceros bicornis) is critically endangered. Like other megafauna, the species is managed in parks and is often translocated to expand their range into reserves where they have been extirpated. Management of genetic variation has been identified as an important consideration in long-term management plans for many wild and captive endangered species including black rhino. In this thesis I examined the contemporary levels of genetic variation within the black rhinoceros (D. b. minor) in KwaZulu-Natal (KZN), South Africa, and specifically the relict source population at Hluhluwe-iMfolozi Game Reserve (HiP), and how this information can be incorporated into management decisions to improve the long-term viability and persistence of the population. Previous studies have examined levels of genetic variation and differentiation among the three black rhino subspecies (D. b. minor, D. b. michaeli and D. b. bicornis) in an attempt to resolve their taxonomy and to establish baseline genetic assessments for managing populations. However, there has been a lack of genetic information based on the variable mitochondrial DNA (mtDNA) control region of the KZN metapopulation and a direct comparison of microsatellite variability between the D. b. minor populations of KZN and Zimbabwe. The specific objectives of this study were to: (1) determine the DNA sequence of the mtDNA control region of three subspecies and estimate the level of variation within the HiP source and KZN metapopulation and compare the results with D. b. minor outside KZN and the other two subspecies; (2) use ten microsatellite DNA markers to estimate the levels of heterozygosity and allelic diversity in the HiP source and KZN metapopulation and compare results to previously published microsatellite data (specifically native Zimbabwe D. b. minor; and (3) use VORTEX Population Viability Analysis (PVA) and HiP vital rates to model the effects of increasing population size and supplementation, and investigate what management scenarios would be most effective for minimizing the loss of genetic variation caused by genetic drift with HiP...</p>

Genetic Management of Wild and Translocated Black Rhinoceros in South Africa’s KwaZulu-Natal Region

<p>The African black rhinoceros (Diceros bicornis) is critically endangered. Like other megafauna, the species is managed in parks and is often translocated to expand their range into reserves where they have been extirpated. Management of genetic variation has been identified as an important consideration in long-term management plans for many wild and captive endangered species including black rhino. In this thesis I examined the contemporary levels of genetic variation within the black rhinoceros (D. b. minor) in KwaZulu-Natal (KZN), South Africa, and specifically the relict source population at Hluhluwe-iMfolozi Game Reserve (HiP), and how this information can be incorporated into management decisions to improve the long-term viability and persistence of the population. Previous studies have examined levels of genetic variation and differentiation among the three black rhino subspecies (D. b. minor, D. b. michaeli and D. b. bicornis) in an attempt to resolve their taxonomy and to establish baseline genetic assessments for managing populations. However, there has been a lack of genetic information based on the variable mitochondrial DNA (mtDNA) control region of the KZN metapopulation and a direct comparison of microsatellite variability between the D. b. minor populations of KZN and Zimbabwe. The specific objectives of this study were to: (1) determine the DNA sequence of the mtDNA control region of three subspecies and estimate the level of variation within the HiP source and KZN metapopulation and compare the results with D. b. minor outside KZN and the other two subspecies; (2) use ten microsatellite DNA markers to estimate the levels of heterozygosity and allelic diversity in the HiP source and KZN metapopulation and compare results to previously published microsatellite data (specifically native Zimbabwe D. b. minor; and (3) use VORTEX Population Viability Analysis (PVA) and HiP vital rates to model the effects of increasing population size and supplementation, and investigate what management scenarios would be most effective for minimizing the loss of genetic variation caused by genetic drift with HiP...</p>

Earless Diceros bicornis in the Etosha National Park, Namibia (Perissodactyla: Rhinocerotidae)

The syndrome of ear pinnae absence was recorded in three individuals of the black rhinoceros (Diceros bicornis) among 71 observed (4.2%) in the Etosha National Park, Namibia, during eight visits in 2013–2020. In two cases, the syndrome comprised bilateral absence of the pinna and certain damage of the tail, while in one case, only unilateral lack of the ear pinna was recorded without any damage of the other pinna and tail.

Practical Management of Iron Overload Disorder (IOD) in Black Rhinoceros (BR; Diceros bicornis)

Critically endangered black rhinoceros (BR) under human care are predisposed to non-hemochromatosis Iron Overload Disorder (IOD). Over the last 30 years, BR have been documented with diseases that have either been induced by or exacerbated by IOD, prompting significant efforts to investigate and address this disorder. IOD is a multi-factorial chronic disease process requiring an evidence-based and integrative long-term approach. While research continues to elucidate the complexities of iron absorption, metabolism, and dysregulation in this species, preventive treatments are recommended and explained herein. The aim of this report is to highlight the accumulated evidence in nutrition, clinical medicine, and behavioral husbandry supporting the successful management of this disorder to ensure optimal animal health, welfare, and longevity for a sustainable black rhinoceros population.