ABSTRACT
Morphological and morphometric traits were used to determine the relationship among Red
(Auraki), Black (Duni), White (Fari), Brown (Idabari) and Brown-white (Idabari-fari) donkeys at
different ages. A total of 700 donkeys were used for the study. The morphological data were
collected on hair type, Coat colour, Skin type, Coat colour pattern, Tail shape, Eye colour and Head
profile.Morphometric measures taken were body weight, head length, head width, ear length, neck
length, neck circumference, shoulder width, height at withers, heart girth, Body length and Tail
length. Data obtained were subjected to different statistical analysis to determine the distribution of
phenotypic traits across classes based on morphological traits. ANOVA was used to determine the
effect of various classes and morphological factors on morphometric indices; correlated relationship
among morphometric traits for different classes, sex and strains were carried out; principal
component analysis of morphometric traits, prediction equation for body weight based on
morphometric measurements, discriminant analysis for the identification of donkeys with high
discriminant powers and cluster analysis to classify donkeys into different genetic groups were
carried out. Significant variations was observed between morphological and morphometric (P<0.01)
traits. The results of the study showed that the short-smooth hair type (75%), brown coat colour
(86%), thick skin type (75%), solid coat colour pattern (97%), pendent tail shape (58%), black eye
colour (95%) and straight head profile (86%) were preponderant in the studied populations. The
correlated relationships among morphometric measurements varied significantly (p<0.05, 0.01) with
age in pooled data and within strains. Coefficients were very high across sexes within strains. Body
weight was positively and negatively correlated with other measurements due to the effect of age.
Principal component indices had higher loadings for head length (0.82), ear length (0.65), neck
length (0.68), neck circumference (0.72), shoulderwidth (0.83), height at withers (0.80), heart girth
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(0.79) and body length (0.84) in PC1 across the strains. Sexual loadings indicated male having better
prediction result when body volume and length components are considered while females are better
evaluated using length and shape related measures. The BL (R2
=97%), HW (R2
=99%) and HG
(R2
=100%) predominated as the major single most important predictors of body weight in a stepwise
regression across the sex and age categories. Brown-fari (Idabari-fari) donkey strain was highly
discriminated against with high discriminating power and this could be classified as a distinct strain
of donkey. Cluster analysis of qualitative traits of donkeys using UPMGA revealed high level of
dilution of the genetic pool. It is therefore concluded that donkeys in Northwestern Nigeria can be
characterized using their morphological and morphometric traits. However, for their distinct
classification, into the four (4) existing strains, body weight, neck circumference and tail length
cannot be used; rather a more appropriate yardstick is the use of skin type (36%) and tail shape
(24%) which had high genetic distance estimate.
TABLE OF CONTENTS
Page
Cover page………………………………………………………………………………………………………..i
Title page……..……………………………………………………………………………………….ii
Declaration………..………………………………………………………………………………………iii
Certification……..……………….……………………………………………………………………iv
Dedication…………………………………………………………………………………………………v
Acknowledgements…………………………………………………………………………………….vi
Table of content……………………………………………………………………………………..viii
List of tables……………………..………………………..……………………………………………xiii
List of figures……..…………………………………………………………..……………………..xvi
List of plates……..……………………………………..………………………………………….xviii
List of appendices……………………………………………………………………………………xix
Abstract………………………………………………………………………………………………….xx
CHAPTER ONE ………………………………………………………………………………………………………………… 1
1.0 INTRODUCTION…………………………………………………………………………………………………….. 1
1.1 Justification of the Study …………………………………………………………………………………………… 3
1.2 Specific Objectives…………………………………………………………………………………………………….. 4
1.3 Research Hypotheses…………………………………………………………………………………………………. 4
CHAPTER TWO ……………………………………………………………………………………………………………….. 5
2.0 LITERATURE REVIEW………………………………………………………………………………………….. 5
2.1 Origin and Domestication of Donkeys in the World ……………………………………………………. 5
2.2 Estimates and Distribution of Donkeys in the World ………………………………………………….. 6
2.2.1Donkey populations in America and Caribbean countries ………………………………………………….. 6
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2.2.2Donkey populations in the Middle East and Asian countries…………………………………..15
2.2.3Donkey population in Europe ………………………………………………………………………………………. .15
2.2.4 Donkey populations in African countries…………………….………………..………………………..18
2.3 History and Spread of Donkeys in Africa……………………..……………………………….18
2.3.1History, distribution and strains of donkeys in Nigeria …………………………………………………….. 19
2.3.2 Production and reproduction characteristics of donkeys under traditional management. …….. 22
2.3.3 Classification of donkeys…………………………………………………………………………………………… 22
2.3.4 Strains of donkeys in Nigeria…………………………………………………………………..24
2.2.5 Classification of Nigeria donkey………………………………………………………………26
2.3.6 Method of assessing strain variation……………………………………………………………………………… 32
2.3.7 Live weight, body measurements, body conformation traits and factors affecting them. ……… 32
2.3.8 Phenotypic characterization…………………………………………………………………………………………. 34
CHAPTER THREEE……………………………………………………….……………..………..37
3.0 MATERIALS AND METHODS ………………………………………………………………………………….. 37
3.1 Study Location ……………………………………………………………………………………………………………. 37
3.2 Sampling Size and Sampling Structure ………………………………………………………………………… 49
3.3 Age Determination………………………………………………………………………………………………………. 50
3.4 Data Collection……………………………………………………………………………………53
3.4.1 Phenotypic characterization…………………………………………………………………………………………. 53
3.4.2 Morphological measurement ……………………………………………………………………………………….. 53
3.4.3 Morphometric measurement ………………………………………………………………………………………… 53
3.4.4 Statistical analysis………………………………………………………………………………………………………. 57
3.4.5 Phenotypic frequency analysis of morphological traits……………………………………………………. 58
3.4.6 Analysis of variance of morphometric traits…………………………………………………………………… 58
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3.4.7 Correlation analysis ……………………………………………………………………………………………………. 58
3.4.8 Principal component analysis of morphometric traits ……………………………………………………… 59
3.4.9 Principal component analysis procedures………………………………………………………………………. 59
3.4.10 Regression analysis…………………………………………………………………………………………………… 61
3.4.11 Discriminant analysis………………………………………………………………………………………………… 62
3.4.12 Classification analysis……………………………………………………………………………………………….. 62
3.4.13 Cluster analysis……………………………………………………………………………………………………….. 63
CHAPTER FOUR………………………………………………………………………………….64
4.0 RESULTS …………………………………………………………………………………………………………………… 64
4.1 Morphological Traits Characterization of Donkeys………………………………………………………. 69
4.2 Factors Affecting Qualitative Traits of Donkeys …………………………………………………………… 70
4.3 Morphometric Characterization of Donkeys and Factors Affecting them……………………… 71
4.4 Measures of Relationships and Associations in Donkeys……………………………………………… 118
4.5 Classification of Donkeys of Northwestern Nigeria……………………………………………………… 143
CHAPTER FIVE………………………………………………………………..…………………166
5.0 DISCUSSION………………………………………………………………………………………………………….. 166
5.1 Distribution of Morphological Characteristics of Studied Donkey Population……………… 166
5.2 Morphometric Characterization of Donkeys and Factors Affecting them…………………….. 167
5.2.1 Distribution of morphological traits of donkeys by sex……..…………..…………………….167
5.2.2 Within age group morphometric characteristics of donkeys …………………………………………… 167
5.3 Effect of Strain, Age, Sex and Location on Morphometric Traits of Donkeys ……………… 168
5.3.1 Effect of Strain on morphometric traits of donkeys……………………………………………………….. 168
5.3.2 Effect of age on morphometric traits of donkeys………………………………………………………….. 168
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5.3.3Effect of sex on morphometric traits of donkeys……………………………………………………………. 169
5.3.4Effect of location on morphometric traits of donkeys…………………………………………………….. 170
5.4 Measures of Relationships and Associations in donkeys………………………………………………. 171
5.4.1 Correlated relationship among morphometric traits of donkeys………………………………………. 171
5.4.2 Prediction of body weight using morphometric measurements……………………………………….. 172
5.4.3 Principal Component Analysis of morphometric traits ………………………………………………….. 173
5.4.4 Principal component analysis of metric measures and their contribution to live body weight of
donkeys by Age ………………………………………………………………………………………………………. 173
5.4.5 Principal component analysis of metric measures and their contribution to live body weight of
donkeys by sex ……………………………………………………………………………………………………….. 173
5.4.6 Principal component cluster analysis of morphological traits of donkeys ………………………… 174
5.5 Classification of Donkeys of Northwestern Nigeria…………………………………………………………. 175
5.5.1 Discriminant analysis for strain classification……………………………..…………………175
5.5.2 Stepwise discriminant analysis to determine the variables with more discriminated power than
others…………………………………………………………………………………………………………………….. 175
5.5.3 Canonical discriminant analysis to match the donkey strains into genetic groups (clusters).. 176
5.5.4 UPMGA (Unpaired Mean Grade Average) cluster between populations for studied
morphological traits of donkeys………………………………………………………………………………… 176
CHAPTER SIX……..………………………………………………………………………………….178
6.0 Summary, conclusions and recommendations…………………………………………………………….. 178
6.1 Summary…………………………………………………………………………………………………………………… 178
6.2 Conclusions……………………………………………………………………………………………………………….. 180
6.3 Recommendations……………………………………………………………………………………………………… 183
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REFERENCES…………………………….…………………………………………………….184
APPENDICES………………………………….………………………………………..………..196
CHAPTER ONE
1.0 INTRODUCTION
Donkey is one of the ancient domesticated livestock in the history of mankind. In 1992, the
world donkey population was estimated to be about 44 million (FAO, 1992).The highest
number of the world donkey exists in Asian countries, followed by African and Latin America
(Fernando and Starkey, 2004). Recent surveys revealed that China has the highest donkey
population of about 11 million followed by Ethiopia with about 5 million donkeys (Starkey
and Starkey, 1997; FAO, 2003). Nigeria is endowed with a donkey population of about
900,000 (RIM, 1992)
Nigeria is one of the countries where donkeys contribute to the daily socio-economic
activities of the citizens. The current population of Nigeria is estimated to be over 173.60
million people (NBS, 2013). More than 70 million Nigerians are smallholder farmers residing
in rural areas with very poor infrastructural facilities. Therefore, donkeys help to transport
people and goods to the rural markets, convey sick people to the hospital, fetch water from the
river or convey animal manure to the farms during the dry season. Even in urban areas,
donkeys are used by people for small-scale transport services such as transportation of
building materials and food items (grains) in Northern part of the country.
Most of the literature from Nigeria about donkey is focused on the use of donkeys as draught
animals (Musa, 1978; Katsina, 1990; Hassan and Bode, 1990; Mohammed, 2000). The use of
donkeys as draught animals in rural areas has increased considerably, which has improved the
involvement of small-scale farmers in the market economy (Fernando and Starkey, 2004; Starkey and
Starkey, 2004). In Nigeria about 16,000 donkeys are transported yearly from the Northern states to the
Southern part of the country for meat (Blench, 2004b). They also provide greater mobility which are
used for carrying firewood, loads, including water, house-hold structures, goods and children
2
(Marshall and Weissbrod, 2011). Presently, donkeys are used in the production of milk for children,
who are allergic to bovine milk (Carrocioet al., 2000; Muraro et al., 2002; Caldinet al., 2005)
Donkeys have been playing significant socio-economic roles to humans since ancient times.
For example, pictures of donkeys were seen in some parts of ancient Egypt (Rosselet al.,
2008). Donkeys and their related species (for example, Mules) help to convey weapons and
soldiers during wars (Fernando and Starkey, 2004)
There are four major strains of donkeys in North West Nigeria which are clearly identified by
coat colours, that is, Auraki (Rust or red), Duni (Dark brown to black), Fari (Pale cream to
white), and Idabari (Grey to light medium brown)(Blench et al.,1990; Starkey and Fielding,
2004). The coat colour is sometimes used as a determining factor for the price of a donkey in
most parts of North West Nigeria (Blench et al., 1990). Idabari strain is the most popular
donkey variety among the smallholder farmers and was reported to cost higher than the other
types (Blench et al., 1990).Generally, donkeys with grey to light medium brown coat colour
fetch higher prices compared to other types (Blench et al., 1990). On the other hand, donkeys
with pale cream to white coat colour cost less because their population is very small which
make them less popular compared to Idabari strain. The Fulani, Kanuri, Hausa and other
tribes in Northern Nigeria have culture of keeping donkeys for different activities (Blench,
1997).
The characterization of domestic animal on the basis of their diversity and relationship is
essential to meet future needs in Africa and Nigeria in particular. Genetic reserves capable of
readily responding to directional forces imposed by broad spectrum of environment must be
maintained. Maintaining genetic diversity is an insurance package against future adverse
conditions. The first step in the characterization of local genetic resources is based on the
3
knowledge of variation in the morphological traits (Delgado et al., 2001). Given that the
majority of the genes influencing body conformation of an animal are of common action and
not local, the formation of one part is found narrowly correlated with the formation of the
other (Lerner and Donald, 1996). Morphological variability has also been used to assess
diversity and relationship in some breeds of livestock (Akpa et al., 1998, Crepaldiet al., 2001,
Salako and Ngere, 2002, Zaitounet al., 2005).
1.1 Justification of the Study
Status of donkey resources is poorly understood, as well as the ongoing transformation of the
livelihood systems that support them. No clear classification for donkeys exists but generally,
they were being classified according to their coat colour (Blench et al., 1990). Some are rust
or red, dark brown to black, pale cream to white, and grey to light medium brown. In addition
to distinct differences based on coat colour among donkey species, they are also clear
phenotypic variations among strains or within strains. Very little is known about the
morphological and morphometric relationships of Donkey strains in Nigeria. There is
relatively limited information available on phenotypic diversity in Donkeys. Recent
classification of donkeys is based on colour alone; there is need for more intense methods of
classification. Such methods should include means of evaluating the quantitative and
qualitative differences that are observable in this species. Such methods can include
morphological and morphometric classifications.
The aim of this study therefore, is to determine the phenotypic diversity between and within
donkey strains in Nigeria using morphometric and morphological characteristics.
4
1.2 Specific Objectives
The specific objectives of this study are to:
1. Morphologically characterize the donkeys for some economic importanttraits
2. Morphometrically characterize the donkeys in the study area
3. Determine the possible factors that can affect these traits.
4. Determine the relationships that exist amongst these traits; and by extension,
define the predictability of body weight of these donkeys.
5. Define the possible route(s) for the classification of the existing donkey strains.
1.3 Research Hypotheses
Null Hypothesis (Ho): There is no relationship among strains of donkey in Nigeria using
morphological and morphometric characteristics.
Alternative Hypothesis (Ha): There is relationship among strains of donkey in Nigeria using
morphological and morphometric characteristics.
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