Practicality of using impala (Aepyceros melampus)

221 Pages·2017·4.11 MB·English

Practicality of using impala (Aepyceros melampus) as
a research model

By

Gareth Edward Zeiler
BVSc(Hons), MMedVet(Anaesth), Dip ECVAA, Dip ACVAA

Submitted for the degree of Doctor of Philosophy (PhD)
in the Department of Paraclinical Sciences
in the Faculty of Veterinary Science University of Pretoria

PROMOTER: Prof Leith CR Meyer

Date submitted: February 2018

© University of Pretoria
DECLARATION
I, Gareth E. Zeiler, hereby declare that the research presented in this thesis, was conceived and
executed by myself, under guidance from my promoter.

Neither the substance, nor any part of the thesis has been submitted in the past, or is to be submitted
for a degree at the University of Pretoria or any other University.

This thesis is presented for fulfilment of the requirements for degree of Doctor of Philosophy (PhD).

Signature: _______________________ Date: ________________________
Gareth E. Zeiler

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ACKNOWLEDGEMENTS

Drs Christina Gerlach (Germany) and Roxanne Buck (South Africa) for all their assistance and
participation in the highly successful collaborative study.
Dr Maya Kummrow (Germany) for initiating the collaborative study and coordinating logistical and
project management tasks required in Europe. Prof Sabine Kästner (Germany) for her technical
expertise and assistance during the data collection of the collaborative study.
Staff members of the Department of Paraclinical Sciences who provided logistical support and hosted
our research teams during the study, especially in the procedure room.
Students (of various years, including postgraduate exchange students) of the Faculty of Veterinary
Science who helped with the husbandry and handling of the impala.
The Hannover and Wuppertal Zoos, University of Hannover, the South African Veterinary Foundation
and the Faculty of Veterinary Science, University of Pretoria for their generous contribution to funding
the collaborative research project.
My Wife, Beaulah, thanks for being there for me during the turbulence of yet another degree.
Lastly, to Prof Leith Meyer, my Promoter. He has provided me with guidance and excellent technical
advice and supportive encouragement to finally complete the writing this thesis.
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CONTENTS
DECLARATION ...................................................................................................................................... ii
ACKNOWLEDGEMENTS ...................................................................................................................... iii
LIST OF TABLES ................................................................................................................................. vii
LIST OF FIGURES .............................................................................................................................. viii
LIST OF ABBREVIATIONS ................................................................................................................... ix
THESIS SUMMARY ............................................................................................................................. xiii
Practicality of using impala (Aepyceros melampus) as a research model ........................................ xiii
Chapter 1 ................................................................................................................................................ 1
General introduction, literature review, scope of the thesis ................................................................ 1
General introduction................................................................................................................... 1
Literature review ........................................................................................................................ 2
1.2.1 Chemical immobilisation and general anaesthesia defined ............................................ 2
1.2.2 Physical and chemical techniques used to capture impala ............................................. 7
1.2.3 General anaesthesia techniques used to anaesthetise impala ..................................... 19
1.2.4 Drugs used during chemical capture and general anaesthesia of impala .................... 22
1.2.5 Physiological effects of chemical capture and general anaesthesia in impala ............. 49
1.2.6 Capture and anaesthesia associated mortalities in impala ........................................... 55
1.2.7 Behaviour characteristics of impala ............................................................................... 56
1.2.8 Impala research models ................................................................................................ 58
1.2.9 Short and long-term captive management of impala..................................................... 60
1.2.10 Welfare and ethics related to captive management of impala in research ................. 61
Scope of the thesis .................................................................................................................. 65
1.3.1 Problem statement ........................................................................................................ 65
1.3.2 Aims of the thesis .......................................................................................................... 66
Chapter 2 .............................................................................................................................................. 71
Comparison of thiafentanil-medetomidine to etorphine-medetomidine immobilisation of
impalas (Aepyceros melampus) ........................................................................................................ 71
Abstract .................................................................................................................................... 72
Introduction .............................................................................................................................. 73
Materials and Methods ............................................................................................................ 73
Results ..................................................................................................................................... 77
Discussion ................................................................................................................................ 79
Conclusions ............................................................................................................................. 84
Chapter 3 .............................................................................................................................................. 85
Etorphine-ketamine-medetomidine total intravenous anaesthesia in wild impala
(Aepyceros melampus) of 120 minute duration ................................................................................ 85
Abstract .................................................................................................................................... 86
Introduction .............................................................................................................................. 87
Materials and Methods ............................................................................................................ 87
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Results ..................................................................................................................................... 92
Discussion ................................................................................................................................ 97
Conclusions ........................................................................................................................... 101
Chapter 4 ............................................................................................................................................ 102
Blood acid-base status in impala (Aepyceros melampus) immobilised and maintained under
total intravenous anaesthesia using two different drug protocols ................................................... 102
Abstract .................................................................................................................................. 103
Introduction ............................................................................................................................ 104
Materials and Methods .......................................................................................................... 107
Results ................................................................................................................................... 110
Discussion .............................................................................................................................. 115
Conclusions ........................................................................................................................... 119
Chapter 5 ............................................................................................................................................ 121
Captive management of wild impala (Aepyceros melampus) during intensive immobilisation
and general anaesthesia study trials ............................................................................................... 121
Abstract .................................................................................................................................. 122
Introduction ............................................................................................................................ 123
Materials and Methods .......................................................................................................... 124
Results ................................................................................................................................... 131
Discussion .............................................................................................................................. 137
Conclusions ........................................................................................................................... 140
Chapter 6 ............................................................................................................................................ 141
Chemical capture of impala (Aepyceros melampus): a review of factors contributing to
morbidity and mortality .................................................................................................................... 141
Abstract .................................................................................................................................. 142
Introduction ............................................................................................................................ 143
Morbidity and Mortality Rates ................................................................................................ 143
Factors Contributing to Morbidity and Mortality ..................................................................... 144
Environmental Factors ........................................................................................................... 145
Drug and Drug Delivery Factors ............................................................................................ 148
Animal Factors ....................................................................................................................... 160
Conclusions ........................................................................................................................... 162
Chapter 7 ............................................................................................................................................ 164
Discussion and general conclusions ............................................................................................... 164
Drug effects of chemical immobilisation and general anaesthesia ........................................ 164
Welfare and ethics of using impala as a research model ...................................................... 172
Final summary and recommendations ................................................................................... 175
REFERENCES .................................................................................................................................... 177
Addendums ....................................................................................................................................... 199
Animal Ethics Certificates ................................................................................................................ 200
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A.1 Certificate V099/13 ...................................................................................................... 200
A.2 Certificate V012/16 ...................................................................................................... 202
Proof of published articles ............................................................................................................... 203
A.3 Comparison of thiafentanil-medetomidine to etorphine-medetomidine
immobilisation of impalas (Aepyceros melampus) ................................................................... 203
A.4 Etorphine-ketamine-medetomidine total intravenous anaesthesia in wild
impala (Aepyceros melampus) of 120-minute duration ........................................................... 204
A.5 Blood acid-base status in impala (Aepyceros melampus) immobilised and
maintained under total intravenous anaesthesia using two different drug protocols ............... 205
A.6 Captive management of wild impala (Aepyceros melampus) during intensive
immobilisation and general anaesthesia study trials ................................................................ 206
A.7 Chemical capture of impala (Aepyceros melampus): a review of factors
contributing to morbidity and mortality ..................................................................................... 207

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LIST OF TABLES
Table 1.1 The signs of general anaesthesia, as described and tabulated by Arthur Guedel in 1937. ... 3

Table 2.1 Physiological variables obtained from impala (Aepyceros melampus) immobilised with
thiafentanil-medetomidine and etorphine-medetomidine combinations. .............................................. 78

Table 3.1 Simple descriptive scoring systems used to determine the quality of immobilisation,
endotracheal intubation and recovery in impala (Aepyceros melampus) undergoing an etorphine-
ketamine-medetomidine total intravenous anesthesia (TIVA) infusion of 120 minute duration. ........... 88

Table 3.2 Equations used to calculate the oxygenation and ventilation indices in impala (Aepyceros
melampus) undergoing an etorphine-ketamine-medetomidine total intravenous anaesthesia (TIVA)
infusion of 120 minute duration. ............................................................................................................ 92

Table 3.3 Time interval and drug dosage related data reported as median (interquartile range; IQR)
for nine impala (Aepyceros melampus) that were immobilised with etorphine-medetomidine and
underwent an etorphine-ketamine-medetomidine total intravenous anaesthesia (TIVA) infusion of 120
minute duration. .................................................................................................................................... 93

Table 3.4 Physiological and calculated parameters of nine impala (Aepyceros melampus) after
etorphine-medetomidine immobilisation followed by an etorphine-ketamine-medetomidine total
intravenous anaesthesia (TIVA) infusion of 120 minute duration. Parameters reported as median
(IQR) at 30 minute intervals for the entire 120 minute duration of infusion. ......................................... 96

Table 4.1 Calculations used to calculate variables of interest to explain the acid-base balance in
healthy impala (Aepyceros melampus) undergoing immobilisation and general anaesthesia using two
different drug protocols. ...................................................................................................................... 106

Table 4.2 Measured and calculated values obtained from healthy impala (Aepyceros melampus)
undergoing immobilisation and general anaesthesia using two different drug protocols. .................. 113

Table 5.1 Drug protocols used to chemically capture impala (Aepyceros melampus) during six
different captures. The drug protocols from the second to the fifth capture were randomly allocated to
impala by two different research teams investigating different immobilisation and total intravenous
anesthesia protocols. .......................................................................................................................... 127

Table 5.2 Immobilisation outcome data of impala (Aepyceros melampus) enrolled into an intensive
research study. .................................................................................................................................... 131

Table 5.3 Serial parameters monitored in impala (Aepyceros melampus) to help indicate welfare
aspects in animals undergoing a 16-week long study investigating the effects of immobilisation and
anaesthesia drug combinations. ......................................................................................................... 134

Table 6.1 Morbidity and mortality rates of impala (Aepyceros melampus) undergoing either physical
(alone or with administration of a tranquiliser) or chemical capture.................................................... 144

Table 6.2 Characteristics of an ideal theoretical immobilisation drug and how frequently used drugs,
or drug classes, to immobilise impala (Aepyceros melampus) compare to this ideal drug. ............... 149

Table 6.3 Drug combinations used to chemically immobilise impala (Aepyceros melampus) during
chemical capture. ................................................................................................................................ 152

Table 6.4 Tranquilisers and sedatives often used in impala (Aepyceros melampus), especially during
transport and relocation to novel areas or short and long-term confinement. .................................... 158

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LIST OF FIGURES
Figure 2.1 Scatter plots with general linear modelling demonstrating the significant difference (p =
0.023) of cortisol concentration (nmol L-1) of impala (Aepyceros melampus) within five minutes after
immobilisation versus the time to recumbency (minutes) between thiafentanil-medetomidine
compared to etorphine-medetomidine. ................................................................................................. 77

Figure 3.1 Spaghetti plots of the etorphine infusion rate (µg kg-1 hour-1) over time in nine impala
(Aepyceros melampus) undergoing an etorphine-ketamine-medetomidine total intravenous
anaesthesia (TIVA) infusion of 120 minute duration. Infusion rate was either increased or decreased
(a fixed 20% change from the initial 40 µg kg-1 hour-1 infusion rate) in a stepwise manner in
accordance to a positive or negative deep-pain response test done at 15 minute intervals,
respectively. Solid black vertical bars indicate a positive deep-pain response. ................................... 94

Figure 3.2 Respiratory rate (breaths minute-1), heart rate (beats minute-1) and mean arterial blood
pressure (mmHg) plotted against the adjusted etorphine infusion rate (µg kg-1 hour-1; solid black line)
over time. All values reported as pooled median (IQR) at 5 minute intervals for the entire 120 minute
etorphine-ketamine-medetomidine total intravenous anaesthesia (TIVA) infusion in nine impala
(Aepyceros melampus). ........................................................................................................................ 95

Figure 4.1 Box plots and whiskers of the independent variables in healthy impala (Aepyceros
melampus) thought responsible for the change in hydrogen ion concentration (pH) in the plasma. .. 111

Figure 5.1 The housing structure used to confine impala (Aepyceros melampus) was a purpose built
2.7 meter high walled outdoor boma (450 m2). ................................................................................... 125

Figure 6.1 Common long bone fracture type presentations during chemical capture of impala
(Aepyceros melampus) in extensive (a: distal limb fractures by tripping during escape attempts or
horning injury) and intensive (b: misplaced dart into the proximal limb bones) housing environments.
............................................................................................................................................................ 146

Figure 6.2 Cervical fracture sustained in an impala (Aepyceros melampus) during chemical capture in
an intensive housing environment where impala attempted to escape by jumping against solid walls of
the enclosure. ...................................................................................................................................... 147

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LIST OF ABBREVIATIONS
Abbreviation(s) Meaning
≈ Almost equal to or approximately equal to
© Copyright sign
°C Degree(s) Celsius
/ Divide by
= Equal to
> Greater than
< Less than
- Minus in arithmetic or to represent a negative number
X or x Multiply by (product of)
% Percent
+ Plus
± Plus Minus
: Ratio indicator or colon
; Semicolon used to separate information
½ Half
2 Squared, to the power of two
5-HT , 5-HT , 5-HT 5-HT Serotonergic receptors
1A 4 7,
AG Anion gap
AMPA Alpha-amino-3-hydroxy-5methyl-4-isoxazolepropionic acid receptor
ANOVA Analysis of variance
ARDS Acute respiratory distress syndrome
Atot Total weak acids
BE Base excess
Beats min-1 Heart beats per minute
Breaths min-1 Breaths per minute
Ca++ Calcium ion
cAMP Cyclic adenosine monophosphate
Cl- Chloride ion
CO Carbon dioxide
2
DA1 and DA2 Dopamine receptors type 1 and 2
DOP Delta-opioid receptor
ET Endotracheal
ET-tube Endotracheal tube
et al. et alia meaning “and others”
F ´O Fractional exhalation of oxygen
E 2
FiO Fractional inspiration of oxygen
2
GABA Gamma-aminobutyric-acid
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GABA Gamma-aminobutyric-acid receptors type A
A
g dL-1 Gram(s) per decilitre
g L-1 Gram(s) per litre
GPCRs G-protein coupled receptors
H+ Hydrogen ion
H1 Histamine receptors type 1
HCO - Bicarbonate ion
3
[HCO -]:[H CO ] Bicarbonate ion to carbonic acid ratio
3 2 3
H CO Carbonic acid
2 3
H O Water
2
I1 and I2 Imidazoline receptors type 1 and 2
i.e. id est meaning “that is” or “in other words” or “namely”
im Intramuscular
IP Inositol trisphosphate
3
IQR Interquartile range
iv Intravenous
K+ Potassium ion
Ka Effective equilibrium dissociation constant
KOP Kappa-opioid receptor
kPa Kilo Pascal(s)
Kg Kilogram
L L-1 Litre per litre
L min-1 or L minute-1 Litre(s) per minute
log Logarithm
10
m Meter(s)
m2 Meter(s) squared
MAP Mean arterial blood pressure
Max Maximum
Mean Average
mEq Milliequivalence(s)
mEq L-1 Milliequivalence(s) per litre
mg Milligram(s) reported as a total dose
mg dL-1 Milligram(s) per decilitre
mg kg-1 Milligram(s) per kilogram
mg kg-1 hour -1 Milligram(s) per kilogram per hour
mg ml-1 Milligram(s) per millilitre
Min Minimum
ml Millilitre(s)
ml kg-1 Millilitre(s) per kilogram
ml kg-1 hour-1 Millilitre(s) per kilogram per hour
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