TABLE OF CONTENTS
Cover Page:………………………………………………………………………………………………….. i
Title Page:…………………………………………………………………………… ii
Declaration:………………………………………………………………………….. iii
Certification:…………………………………………………………………………. iv
Dedication:…………………………………………………………………………… v
Acknowledgment:……………………………………………………………………. vi
Abstract:………………………………………………………………………………. viii
Table of Contents:……………………………………………………………………… x
List of Tables:…………………………………………………………………………… xvii
List of Figures:…………………………………………………………………………. xx
List of Appendices ………………………………………………………………….. xxi
Abbreviations:………………………………………………………………………………………………….. xxii
CHAPTER ONE
1.0 Introduction:………………………………………………………………… 1
1.1 Problem Statement:…………………………………………………………………………….. 4
1.2 Justification:………………………………………………………………………………………. 4
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1.3 Objectives:………………………………………………………………………………………… 5
CHAPTER TWO
2.0 Literature Review:………………………………………………………… 6
2.1 World’s Goat Populations……………………………………………….. 6
2.2 Economic Importance of the Goat in the Tropics and Subtropics………. 7
2.3 The Indigenous Goats of Nigeria………………………………………….. 8
2.3.1 Breeds and distribution……………………………………………………. 8
2.3.2 Sahel/Desert Goat………………………………………………………….. 9
2.3.3 Red Sokoto Goat…………………………………………………………….. 9
2.3.4 West African Dwarf Goat……………………………………………………. 9
2.4 Present Status of world Goat Productivity…………………………………… 10
2.4.1 Milk Production……………………………………………………………… 10
2.4.2 Tropical dairy goat breeds…………………………………………………… 12
2.5 Goat Production System……………………………………………………….. 12
2.5.1The Subsistence System……………………………………………………….. 13
2.5.2 The Extensive System ……………………………………………………….. 13
2.5.3 The Semi-Intensive System…………………………………………………. 14
2.5.4 The Intensive System………………………………………………………. 14
2.6 Performance characteristics of tropical goats …………………………………. 15
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2.6.1 Fertility and Prolificacy………………………………………………………. 15
2.6.2 Body Weight in goats………………………………………………………… 15
2.6.3 Growth rates………………………………………………………………….. 16
2.6.4 Milk Yield………………………………………………………………….. 17
2.6.5 Nutrients and composition of goat milk …………………………………….. 19
2.6.5.1 Medicinal properties of goat milk………………………………………….. 20
2.6.5.2 Udder Characteristic and Milk production…………………………………. 21
2.6.5.3 Factors influencing milk yield of goats…………………………………….. 23
2.6.6.1: Goat Diseases and Parasites……………………………………………….. 26
2.6.6.2 Preventive measures against goat parasites……………………………….. 27
2.6.7 Mortality in goats………………………………………………………………. 28
2.7 Relationship between Conformation Traits and Milk Production in Small Ruminant .. 29
2.8 Coat Colour Variations in Goats………………………………………………… 30
2.9 Nigeria’s indigenous goats and milk production potential………………………. 32
2.10 Blood biochemical polymorphism in livestock…………………………………. 33
2.11 Potassium…………………………………………………………………………. 34
2.11. 1 Potassium types and production traits………………………………………… 36
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2.12 The haemoglobins ……………………………………………………………….. 37
2.12. 1 Electrophoresis………………………………………………………………… 38
2.12.2 Hemoglobin types and hematological factors…………………………………. 39
2.12.3 Hemoglobin Types and Production Traits…………………………………….. 39
2.12.4 Hemoglobin Types and Adaptation Traits…………………………………….. 41
2.13 Haematological and Biochemical Parameters in goats………………………….. 42
2.14 Biotechnology options for Improving Livestock Production……………………. 43
2.14.1 Multiple Ovulation Embryo Transfer and Open Nucleus Breeding System…… 45
2.14.2 Indicator traits……………………………………………………………………. 45
2.14.3 Genetic Markers and Marker-assisted Selection………………………………… 46
2.14.4 Transgenic Animals………………………………………………………………. 47
2.15 Characteristics of goat breeding programmes……………………………………. 48
2.16 Breeding programmes and traits targeted goat…………………………………. 49
CHAPTER THREE
3.0 Materials and Methods:…………………………………………………………….. 51
3.1 Study Area:………………………………………………………………………….. 51
3.2 The Animals and Management:…………………………………………………… 54
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3.3 The Measurements:………………………………………………… …………. 54
3.3.1 Udder measurement:…………………………………………………………… 55
3.3.2 Milk Yield Characteristics:…………………………………………………….. 57
3.3.3 Measurements of Conformation Traits:……………………………………….. 58
3.4 Blood Collection and Preparation for Analysis:………………………………. 60
3.5 Statistical Analysis:…………………………………………………………….. 61
4.0 Results:…………………………………………………………………………. 69
4.1 Milk Yield Characteristics:……………………………………………………… 69
4.2 Udder Characteristics:………………………………………………………….. 78
4.3 Conformation Traits:…………………………………………………………… 83
4.4 Electrophoretic Haemoglobin Pattern:………………………………………… 88
4.5 Haemoglobin Types, Gene and Genotypic Frequencies:……………………… 91
4.6 Potassium Types, Gene and Genotypic Frequencies:…………………………. 93
4.7 Effect of haemoglobin and Potassium Polymorphism on Milk Yield
Characteristics in Goats:……………………………………………………… 96
4.8 Effect of Haemoglobin And Potassium Polymorphism on Blood
Biochemical Profiles in Goats:…………………………………………………. 98
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4.9 Blood Biochemical Profiles in Goats:……………………………….. 100
4.9.1 Blood Biochemical Profile And Goat Breeds:……………………… 111
4.10 Suitability of Using Polymorphic Genes As Genetic Markers:……… 117
CHAPTER FIVE
5.0 Discussion:…………………………………………………………… 124
5.1 Milk Yield Characteristics:………………………………………….. 124
5.2 Udder Characteristics:………………………………………………. 126
5.3 Conformation Traits:……………………………………………….. 128
5.4 Eletrophoretic Haemoglobin Pattern:………………………………. 130
5.5 Haemoglobin Types, Gene and Gene Frequencies:………………… 131
5.6 Potassium Types, Gene and Genotypic Frequencies:………………. 133
5.7 Haemoglobin and Potassium Polymorphism and their
Relationship With Milk Yield Characteristics In Goats:……………. 134
5.8 Haemoglobin And Potassium Polymorphism And Blood
Biochemical Profile In Goats:……………………………… ………. 135
5.9 Blood Biochemical Profile In Goats:………………………………. 136
5.10 Suitability of Using Polymorphic Genes As Genetic Markers:…… 138
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CHAPTER SIX
6.0 Summary, Conclusion And Recommendation:……………………….. 141
6.1 Summary:……………………………………………………………………………… 141
6.2 Conclusion:…………………………………………………………………………… 144
6.3 Recommendations:………………………………………………………………… 145
References:……………………………………………………………………………. 146
Appendices………………………………………………………….. 176
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CHAPTER ONE
1.0 INTRODUCTION
Nigeria is endowed with large numbers of small ruminants which are yet to be fully investigated
for milk production. Goats are the largest in number among ruminant livestock, totaling about
53.8 million (FAOSTAT, 2008). Goats are predominantly owned by the rural households and
ownership is spread across all human age groups and sexes (Akpa, 1999). Goats form the most
important group of milk producing animals after dairy cattle in both temperate and tropical
agriculture. The dairy goat industry is rapidly gaining importance throughout the world (Bogoro
et al., 1999).
More than any other mammalian farm animal, the goat is the main supplier of dairy and meat
products for rural people, especially in developing countries. As a dairy producer, the goat can
accomplish one of the three aspects of the demand for goat milk. The first one is home
consumption. This demand is increasing because of the growing populations of people, and here
the old saying of the “goat being the cow of the poor people” is quite fitting. The second aspect
of the demand for goat milk is the special interest in goat milk products, especially cheese and
yoghurt, in many developed countries. The third aspect of the demand for goat milk derives from
the affliction of people with cow milk allergies and other gastro-intestinal ailments. These two
latter aspects of the demand for goat milk are quite different from the “goat being the cow of the
poor people”; here, goat milk is wanted or even needed by people of all income levels (Haenlein,
2004).
Poor health and productivity arising from malnutrition in developing countries like Nigeria are
well known problems (IFPRI, 1994). It has been reported that protein malnutrition problem
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persisting in developing countries could be largely mitigated using small ruminants for both meat
and milk production (Freund, 2000). Therefore, taking advantage of the genetic diversity of the
indigenous goats, it would be possible to improve the milk production potential of the indigenous
goats through selection.
Genetic variations among the small ruminant varieties that are indigenous to Nigeria have been
the focus of geneticists. This is because the amount of genetic variation detectable in an animal
population is related to the magnitude of genetic improvement achievable within the species
(Salako et al., 2007; Akpa et al., 2011). Advances in the field of biotechnology have led to
introduction of techniques such as routine electrophoresis employed for the detection of
polymorphism at protein and enzyme loci as well as other serological and immunogenetic
procedure for measurement of variation (Salako et al., 2007) . Information from this type of
study could be useful as genetic markers for important economic characters and diseases and
could aid significantly in selection of superior animals for breeding purposes. Research and
reports on Nigeria indigenous goats based on molecular standpoint are limited.
Blood parameters have been widely used to determine genetic diversity in animal population.
The concentration of metabolites in animal blood is an important indicator associated with
production. (Casasus et al., 2002). The development of different traits in animals depends on the
good order of a complex of biochemical processes each of them functioning under a rigorous
genetic control (Mariana et al., 2006).
Haemoglobin, an important erythrocyte protein inherited by co dominance in Mendelian fashion
has been reported to be a useful marker through which many economic traits, with which it is
associated, have been improved in farm animals (Akinyemi and salako 2010). Potassium is one
of the intracellular elements which constitute the structure of an organism. Its main function is to
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regulate intracellular density of cells (Ellory and Tucker, 1970). In ruminant, there are two
potassium types, high Potassium (HK) and low potassium (LK). The low Potassium is dominant
to the (HK) type. The HK and LK allele gene frequencies are different among goat breeds
(Pembeci, 1978); and potassium types have been proved to be genetically controlled (Al-
Samarrae and Younis, 2011).
Haemoglobin and potassium types can be determined easily at postnatal period of young
animals and these components are not affected by environmental factors (Gurcan et al., 2010).
Many studies have been conducted using different sheep and goat breeds to determine the level
of various blood parameters and to evaluate the any relationship between blood biochemical
polymorphism and production traits (Gonzales et al., 1984; Soysal and Ulku, 1998; Shahrbabak
et al., 2009; Gurcan et al., 2010; Akinyemi and Salako 2010). These associations have been
utilized as a polymorphic marker among domestic animals.
Coat colour of animals is very important to a characteristic that allows easy differentiation
among individuals and breeds by farmers. Coat colours allow one to differentiate among
individuals within the same breed in terms of intensity, patterns and amount of each colours
(Becerril et al., 1994). Coat colour has been shown to be related to productivity, because the
ability of an animal to eliminate excessive body heat to its surrounding environment depends on
morphological characteristics of hair coat colours (Maia et al., 2005; Mustafa et al., 2011).
Body measurements are related to milk yield either genetically or phenotypically and could be a
useful tool for predicting milk production (Waheed and Khan, 2011). Body measurements are
important tools for phenotypic description, these measurements include body length, height at
withers, body depth, rump height (Hassan and Ciroma, 1990). Relationship between live weight
31
and body measurement has been reported in some Nigerian breed (Hassan and Ciroma, 1990;
Akinyemi and Salako, 2010; Abubakar, 2009; Ibrahim, 2010).
Although some goat breeding programmes are available in Nigeria, they are mostly centralized
and limited to Research institutes without major effect on the larger goat base population. Given
the ever growing human population, particularly in the urban areas of Nigeria, the concurrent
demand for animal protein is ever increasing. In these over-populated urban areas, the shortage
of adequate grazing and the relatively high maintenance costs of cattle, makes goat farming an
alternative for milk production.
1.1 Problem Statement
Nigeria’s population has grown over the years to about 170 million . The average protein intake
has remained inadequate protein. The indigenous breed of goat can be improved through proper
breeding and selection to increase dairy product supplies, to supplement cow milk and to provide
supplementary income to the smallholder goat producers and milk processosr.
1.2 Justification
In Nigeria, there is little information on dairy characteristics of the indigenous goats based on onfarm
research, most reports on milk production of indigenous goats emanated from Research
Institutes and Universities.
There is limited information on the association between blood biochemical profiles and milk
production traits in Nigerian indigenous goats. More so, there is paucity of information on
relationship between coat colour and milk yield characteristics in these indigenous breeds. All
these necessitated this research. If the ever widening shortfalls in dairy product supplies are to be
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met through local production, there is need to take advantage of genetic diversity of indigenous
goats in order to supplement milk from cow. Information from this research will be good
alternative to the conventional methods of trait selection based on performance records once
these genes are proven to be associated with milk yield and conformation traits; and it will also
improve our knowledge of the genetic background of our indigenous goat herds.
1.3 Objectives
The objectives of this research were to:
1) Evaluate milk production characteristics, udder and body conformation traits and blood
biochemical profiles of Nigerian indigenous goats.
2) Determine the factors affecting milk yield, udder and body conformation traits in
Nigerian indigenous goats.
3) Establish the relationship between milk production characteristics, udder and body
conformation traits; and blood biochemical profiles in Nigerian indigenous goats.
4) Determine haemoglobin and potassium polymorphism as well as their gene and
Genotypic frequencies; and their effects on milk yield characteristics and blood
biochemical profiles.
5) Determine the potential marking ability of the polymorphic genes as selection tool for
conformation and milk production traits.
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