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EFFECT OF COAT COLOUR AND SEX ON PHYSIOLOGICAL INDICES OF
WEST AFRICAN DWARF GOAT
BY
ADEBOWALE, RIDWAN Adeyemi
MATRIC NO: 2008/0332
A PROJECT REPORT SUBMITTED TO THE
DEPARTMENT OF ANIMAL PRODUCTION AND HEALTH
COLLEGE OF ANIMAL SCIENCE AND LIVESTOCK PRODUCTION
FEDERAL UNIVERSITY OF AGRICULTURE, ABEOKUTA
IN PARTIAL FULFILLMENT FOR THE AWARD OF BACHELOR OF
AGRICULTURE (B. Agric).
JANUARY, 2014
CERTIFICATION
This is to certify that this project was carried out by ADEBOWALE RIDWAN
ADEYEMI, with Matriculation number (2008/0332) of the Department of Animal Production
and health, College of Animal Science and Livestock Production, Federal University of
Agriculture, Abeokuta. Ogun State, Nigeria, under my supervision.
……………………………........ ……………………
Dr. O. S. Sowande Date
SUPERVISOR
.................................................... ...................... ..............
Prof. A.B.J Aina Date
Head of Department
DECDICATION
To Almighty Allah, the lord of the entire universe and the one who teaches man that which he
does not know.
Also to my mum and dad for their undying loves for me.
ACKNOWLEDGEMENT
My sincere gratitude to Almighty Allah the lord of the entire universe who spare my live up
to this moment, my gratitude also goes to my parents Mr. and Mrs. Adebowale who stood in
my support morally and financially throughout my stay in school.
Also my sincere appreciation goes to the family of Mr. and Mrs. Latinwo for their
unrelenting support financially and morally I pray that Allah will see you through your
ordeal in life.
Am also using this medium to appreciate my supervisors Dr. O.S Sowande and Dr. O.G.
Sodipe for their contribution and support towards making this work a successful one, I pray
that god will see you through in all your endeavor.
To the head of the department and all the lecturer in the college thanks for your parental
advice and thanks for sharing your knowledge with us.
My special thanks to my uncle Mr. Muyideen Adebowale for his support and also to my
siblings Sodiq, Abeeb, Zainab and Basit.
To all my friends Jimoh Saheed, Olaniyi Mariam, Adeoba Sikiru, Akanji Mutair, Adebowale
Paul, Akintayo Hellen, Okusi Oluwagbeminiyi, Giwa Rabiat and all those that cannot be
mentioned on this pages of paper I want to say thank you for your support, you guys are one
in a million.
TABLE OF CONTENTS PAGE
Title i
Certification ii
Dedication iii
Acknowledgement iv
Table of content v
List of tables viii
Abstract ix
CHAPTER ONE
1.0 INTRODUCTION 1
1.1 Justification 2
1.2 Objectives 3
1.2.1 Broad objectives 3
1.2.1 Specific objectives 3
CHAPTER TWO
2.0 LITERATURE REVIEW 4
2.1 Importance of livestock production 4
2.2 Climatic change 4
2.2.1 Evident and causes of climatic change 5
2.2.2 Effect of climate on livestock production 6
2.2.3 Bioclimatology 7
2.3 Goat 7
2.3.1 West African Dwarf goats 8
2.4 Coat colour 8
2.5 Physiology 9
2.5.1 Physiological Parameters 9
2.5.1.1 Pulse Rate 9
2.5.1.2 Respiratory Rate 10
2.5.1.3 Rectal Temperature 10
2.6 Heat stress in goat 11
2.7 Homeostasis 12
2.7.1Animal response and adaptation to different climate 12
CHAPTER THREE
3.0 MATERIALS AND METHOD 14
3.1 Experimental site 14
3.2 Experimental Animal and Management 14
3.2.1 Feeding 14
3.3 Materials 15
3.4 Experimental Method 15
3.5 Statistical analysis 16
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION 17
4.1 Results 17
4.2 Discussion 22
CHAPTER FIVE
5.0 CONCLUSION AND RECCOMENDATION 25
5.1 Conclusion 25
5.2 Recommendation 25
REFERENCES 26
LIST OF TABLES PAGE
1. Nutrient composition of feed (concentrates) fed to experimental animals. 15
2. Effect of sex on pulse rate, respiratory rate, rectal temperature and
skin temperature of (WAD) goat. 19
3. Effect of coat colour on physiological indices of (WAD) goat. 20
4. Interactive effects of sex and coat colour on physiological indices of
(WAD) goat. 21
ABSTRACT
This study was carried out in the humid tropics of Southwest Nigeria, at the Small
Ruminant Units of the Directorate of University Farms (DUFARMS) of the Federal
University of Agriculture Abeokuta Ogun state. The aim of the study is to evaluate the effect
of coat colour and sex on the physiological indices of West African Dwarf goats. The study
was performed using both sexes consisting of (11 bucks and 7 does). The weight of the
animals ranges from 5.0-11.0kg, the coat colour of the animals ranges from black, brown, tan
and white. The study was carried from late dry season to early wet season between February
to April, the animal were housed based on sex in individual pen. Weekly body weight gain
and daily feed intake were determined. Physiological parameters data were taken in the
morning on rectal temperature, skin temperature, pulse rate and respiratory rate. The does had
a pulse rate of (94.96±0.645 bm-1) which was higher than that of bucks having 92.48±0.499
beats per minutes respectively and there were no significant differences (p>0.05) in
respiratory rate, rectal temperature and skin temperature measured for both bucks and does
goats respectively. The variation in coat colours had a significant effect on pulse rate, and
respiratory rate (p<0.05), white coat coloured goats have the highest value for pulse rate
(97.19±0.099 bm-1) while black coat have the highest respiratory rate (36.72±0.428 fm -1) .
However the effect of the effect of coat colour and sex was significantly different on pulse
rate and respiratory rate (p<0.05) with female white goat having the highest pulse rate
(100.79±1.631 bm-1), while male black goats have the highest value for respiratory rate
(37.43±0.541) flank movement per minute, also the effect of coat colour and sex was not
significant (p>0.05), on rectal temperature for all the coat colours observed for male goats.
The interactive effect coat colour and sex had no significant effect (p>0.05) on skin
temperature. Thus, it can be concluded from this study that coat colour plays a major role in
the adaptation of an animal to a particular environment. Hence, proper management and
environmental conditions must be ensured in order to obtain optimum performance of the
West African Dwarf goats.
CHAPTER ONE
1.0 INTRODUCTION
Goats are one of man’s principal sources of meat and milk. Most goats are found in
the drier part of the developing world (Daramola et al., 2008). The total world goat
population in 2007 was estimated at about 850 million goat of which 728 million were in low
income food deficit countries (FAO Stat 2008). Asia is home to about 545 million goats and
Africa about 245 million.
The West African Dwarf goat is widely distributed across the rainforest belt of
southern Nigeria. They are short-legged and small-bodied animals, weighing between 22 and
26kg (Mourad et al., 2000). They are hardy, small, early maturing, prolific, non-seasonal
breeder and plump, measuring less than 50cm in height and they are trypanosome tolerant
(Adedeji et al., 2011). They also present variable coat colours ranging from black, brown,
grey, red white and combination of these colours in a variety of patterns (Mourad et al.,
2000).
Coat colour is a qualitative trait and an indicator of genetic superiority or productive
adaptability of animals to heat tolerance. Coat colour is mostly controlled by alleles at three
loci (A, B and S), although genes on the extension locus act as modifier genes. It is a highly
repeatable character with a high heritability estimate (Fadare et al., 2012).Varied expression
of qualitative traits (e.g. coat colour) may represent some adaptive mechanisms related to
adaptation and survival of the animals (Oseni et al., 2006).
The thermal environment is a major factor that can negatively affect goat
performance, increase body temperature and respiratory rate are the most important sign of
heat stress in goats (Alam et al., 2011). This result in the significant decrease in dry matter
intake (Holter et al., 1997), milk yield (West, 2003), milk quality (Beede and Shearer, 1996),
and reproductive performance. Hence, physiological adjustment are essential in order to
maintain normal body temperature and to prevent hyperthermia (Al-Haidray, 2000).
The performance of animals is a product of interaction between the environment and
genotype. Since genetic potentials cannot be expressed unless an adequate environment is
provided, the productivity of an animal is affected adversely by extreme climatic conditions.
Proper understanding of how climatic factors affect the physiological response of goats
provides a firm basis of improving their husbandry and health status (Abdalla et al., 2009).
Conclusively this study is aiming to determine the variations in the physiological profile of
West African Dwarf goat of both sexes.
1.1 JUSTIFICATION
Previous experiment carried out by researchers has shown that the pigmentation of an
animal shows a significant effect on the physiological profile of goats, which in turn affect
the productivity of the animal. Also the knowledge of variation of coat pigmentation will
enable breeders and animal producers to select for animals that will respond less to
environmentally induced stress such as temperature, sunlight, rainfall etc. Also, both sex of
animals, (male and female) are required for breeding and productive purposes, there is need
to study the physiological response of both sex of goats to external environment as it will
help to determine the management system to be employed, prediction of diseases and help in
overall herd health maintenance.
This research work focus on the response of (WAD) goat of both sexes and various coat
colours to their external environment changes in relation to the effect on their physiological
profile.
1.2 OBJECTIVE
1.2.1 BROAD OBJECTIVE
To determine the effect of coat colour and sex on the physiological parameters of
West African Dwarf goat.
1.2.2 SPECIFIC OBJECTIVES
To determine the effect of coat colour and sex on pulse rate of West African Dwarf
goat.
To evaluate the effect of coat colour and sex on respiratory rate of West African
Dwarf goat.
To examine the effect of coat colour and sex on rectal temperature of West African
Dwarf goat.
To evaluate the effect of coat colour and sex on skin temperature of West African
Dwarf goat.
CHAPTER TWO
2.0 LITERATURE REVIEW
2.1 IMPORTANCE OF LIVESTOCK PRODUCTION
Livestock are not only important as producers of meat, milk and eggs which are part
of the modern food chain and provides high value protein, they also constitute the main
capital reserves for farming households, serves as strategic reserve that reduce risks and add
stability to the overall farming system (Stienfield, 1998).
At national level, meat and milk production dominate research and development and
planning for the livestock sector. Apart from production of meat and milk the priorities of
small scale and traditional livestock production of small ruminants includes:
Generation and accumulation of capital.
Fulfilling of social cultural and religious requirement and obligations.
Generation of income for farmers.
Provision of food and other direct products (Tropical agriculturalist, 1995).
2.2 CLIMATIC CHANGE
The state of global climate has received unprecedented attention in the past 24 years since
about 1989, possible impact of human activity on the environment has increased significantly
and green house issues are known very much in the public consciousness, perhaps the most
wide range of concern. The idea that human activity in a world reliant on heavy industries
can cause a significant impact on the climate of the whole world was not a serious suggestion
until a decade ago. However, the magnitude of the possible impact of such climate change
have propelled climatic change research to one of the major world priorities in just a few
years (Turnpenny, 1997).
2.2.1 EVIDENT AND CAUSES OF CLIMATE CHANGE
The global climate is extremely variable on all time scales ranging from seconds to
millions of years. The climate is ultimately forced by changes in the balance between the
amount of energy received from solar radiation and the thermal radiation emitted by the earth
as a consequence of it temperature (Houghton et al.,1990: IPPC 1994). Such energy balance
changes are known as radiative forcing. Many variation in climate are caused by
superposition of various effect, such as eccentricity of the Earth orbit and the angle of
inclination of each to the ecliptic, or the plane of the orbit. All the gases in the atmosphere are
relatively poor absorbers of short wave solar radiation, and changing in the concentration of
these gases has a little effect on solar radiation absorbed. However, some gases are good
absorbers of thermal radiation emitted by the earth, most notably carbon dioxide, methane,
and water vapour. Increasing the concentration of these gases result in a decrease in the
thermal radiation emitted into the space and therefore a net increase in the global mean
temperature, this is the green house effect. The natural concentration of gases which enhance
the green house effect are such that the global temperature is more than 300C higher than it
would be where the gases are absent. This is the cause of enhance green house effect and the
extent to which such increase affect the global climate, and the possible scenarios of future
emission are currently of major international concern (Turnpenny, 1997).
The theory that raised carbon dioxide levels due to human activities are likely to cause
a global warming has been in place for more than twenty years. Broecker, (1975) suggested
that the cooling trend observed from 1940-1975 was a natural climatic flunctuation which
compensated for the increased temperature due to carbon dioxide emission. Broeker predicted
a sharp rise in global mean temperature of about 1oC above the 1900 value by the year 2000
(Houghton et al., 1990). In the first series of major reports on the scientific assessment of
climatic change by the International Governmental Panel on Climate Change (IPCC), stated
that “we are certain that emissions resulting from human activities are substantially
increasing the atmospheric concentration of the green house gases, these increase will
enhance the green house effect resulting on average in an additional warming of the earth
surface”.
2.2.2 EFFECT OF CLIMATE ON LIVESTOCK PRODUCTION
The impacts of climates on animal production includes the effect of extreme climates
as well as the effect of global climatic changes hence, the study of animal adaptation
mechanisms and managerial techniques will help to reduce the effects of extreme climates
and climatic changes on animals which is mitigating improvement in animal production
(Khalifa, 2003). Unfavourable environmental conditions as a result of heat stress result in
reduced feed ingestion, slow metabolism causing hypo-function of the thyroid, which affect
growth, reproductive efficiency, food conversion and milk production leading to considerable
economic losses (West, 2003).
Climatic regions can be classified according to its effect on animals to hot, cold and altitude.
The main environmental factors affecting livestock are air temperature ,relative humidity,
radiant heat, precipitation, atmospheric pressure, ultraviolet light, wind velocity and dust
(Hahn et al.,2003). The effect of climate on farm animals depend greatly on the severity and
duration of climatic factors and animal adaptive mechanism. Chronic heat stress affect animal
morbidity, production and reproduction while it has a slight effect on mortality.
Livestock are homoeothermic animals which have the ability to control their body
temperature within a wide range of environmental temperature. Homeostasis is the process of
maintaining a constant internal environment i.e. body temperature, body water, blood
pressure, pH and ionic equilibrium despite variations in the external environment. Under cold
stress, the first animal response is shivering (thermogenesis) in order to increase heat
production until glucocorticoid and thyroid hormones increases through direct effect of cold
stress on hypothalamus (Lacetera et al., 2003). The main impact of climatic changes and
extreme events can be summarized in the effect of hot, cold, and high altitude. The duration,
intensity and recovery from any climatic stress are the most important factors affecting farm
animal’s production and reproduction. The wide definition of animal adaptation is how the
animals can survive and produce under specific climate. Physiological parameters have been
used as an indication of animal adaptability to different climates. Climatic impact on
production and reproduction are good indicators for animal adaptability (Lacetera et al.,
2003).
2.2.3 BIOCLIMATOLOGY
Animal bioclimatology is the science that deals with the inter-relationship between
climate, soil, plants and animals (Hafez, 1968). Also on the other hand animal physiology is
the science that deals with the study of animals in relation to their natural physical
environment, but animal bioclimatology is focused on the interaction between climate and
farm animal production. It involves the description of bio-climatological factors causing
necessity of farm animals adaptation, the morphological and physiological behaviour of farm
animal to natural change and to extreme of the physical environment (Khalifa, 2003).
2.3 GOAT
Goats are considered as small livestock animals compared to bigger animals such as cattle,
camels, and horses (Taylor and Field, 1999). They have four chambered stomach consisting
of the rumen, recticulum, omasun and abomasum (Taylor, 1998). Goats reach puberty
between 3 and 15 months of age depending on the breed and nutritional status (Payne and
William, 1999).
Goats are multipurpose animals producing meat, milk, skin and hairs (French, 1970).
However, out of these products meat is the major form in which goats are consumed in
Nigeria because there is no taboo against it (Peacock, 1996).The meat from goat is preferable
to those from other animal species because of its flavour, tenderness and palatability (Idiong
and Orok, 2008).They are indispensable in marriage and religious rites (Gefu et al., 1994) and
are an insurance against crop failure (Mattewman, 1980). In southern Nigeria, goats are a
ready source of family income and a good medium to establish friendship or restore peace in
the community (Idiong and Udom, 2011).
2.3.1 WESTAFRICAN DWARF GOATS
The West African Dwarf (WAD) goat is a predominantly indigenous breed found in
southern Nigeria (Odeyinka, 2000). They are widely distributed across the rainforest belt of
Southern Nigeria where it makes significant contributions to the livelihoods of impoverished
families. The potentials of WAD goats in poverty alleviation programme are well recognized,
but is still largely untapped. In the humid tropics of South Western Nigeria, goats are higher
in number than sheep (Osinowo, 1992). Goats have advantage over other ruminants because
they walk for long distance in search of feed and this behaviour assist in meeting their
nutrient requirement (Devendra and Mcleroy, 1982). The main feed resources of animal are
native grasses, legumes that occur naturally in grasslands, tree leaves and crop residues.
2.4 COAT COLOUR
Qualitative traits have been studied as possible indicators of genetic superiority or
adaptability with more emphasis on dwarf goats (Ozoje and Mgbere, 2002; Adedeji et al.,
2011). Also reported by Odubote (1994), that coat colour is variable and irregular, including
black, brown, pied and mixed colours. Basic black colour predominated (53.3%) while basic
white and brown goats accounted for 6.8% and 39.9% respectively. Coat color and type is
known to adapt animals to different climatic zones and has considerable influence on the
performance of various stocks (Odubote, 1994; Ebozoje and Ikeobi, 1998). Colour is due to
melanin deposits in the hair which comes in two basic types eumelanin and phaeomelanin.
Eumelanin is usually black, but sometimes brown. It is the pigment responsible for black and
brown areas on goats, or rarely for dusky blue colour. Black wool has long been known to be
due a recessive gene, with heterozygotes for the recessive allele indistinguishable from the
dominant homozygotes (Adalsteinsson et al. 1994).
2.5 PHYSIOLOGY
This is the study of the normal functioning of animals and plants during life and of
the activities by which life is maintained. The study of the function is usually undertaken
along with a study of structure i.e. (anatomy), It includes the study of vital activities in cells,
tissues, and organs in the body and of processes such as contractility of muscle tissue,
coordination through the nervous system, feeding, digestion, excretion, respiration,
circulation and reproduction (www.cc.columbia.edu/cu/cup/).
2.5.1 PHYSIOLOGICAL PARAMETERS
2.5.1.1 PULSE RATE
This is the regular beat rate of the arteries, as the blood is being pumped through them
to the heart (Heath and Olusanya, 1985). It is an easy way to count the heart rate, pulse rate
which is expressed in beats per minutes can be altered rapidly due to external factor such as
temperature or biological activities by the animal itself. Otoikhan, (2009) reported 73 beats
per minutes for West African Dwarf goat. Fasoro (1990) also reported 90.2 beat for West
African Dwarf goat and 96.6 beat per minute for Red Sokoto goats.
The procedure for taking goats pulse includes: ensuring that the goat is calm and
resting, then find the goats artery below and slightly inside the jaw, then the number of heart
beat can be counted with the aid of a stopwatch for 15 minutes then the value can be
multiplied by 4 to get the pulse rate (http://www.dummies.com).
2.5.1.2 RESPIRATORY RATE
This is the frequency of ventilation, i.e. the number of breaths (inhalation – exhalation cycles)
taking place within a set amount of time typically (60 seconds). A normal respiratory rate is
termed eupnea, an increased respiratory rate is termed tachypnea and a lower than normal
respiratory rate is termed bradypnea (en.m.wikipedia.org./wiki/Respiratory rate).
Respiratory rate can change frequently and at the extreme, in a matter of minutes, it is
indirectly influenced by the animal activities and environmental condition. The size of the
animal is related to the respiratory rate. Slee (1979) reported that respiration rate is much
higher during high plane of nutrition in sheep. Fasoro (1990) reported 37.5 beat per minutes
for Red Sokoto goat and 29 beat per minute for West African Dwarf goats, while report from
Otoikihan et al., (2009) stated that the respiratory rate for (WAD) goat is between 20-25
beats per minutes.
The normal respiration rate for an adult goat is between 10-30 breath per minute and
for a kid it is between 20-40 breath per minutes. To count the respiratory rate, simply watch
the goats side when the goat is calm and resting for 60 seconds count one respiration for each
time as the goats side rise and fall. (http://www.dummies.com)
2.5.1.3 RECTAL TEMPERATURE
Rectal temperature is generally used as a measurement of animal core temperature
(Neilson, 1997). Domestic animals are homotherms which tends to maintain a constant body
temperature through a balance of heat gain and loss (Oladimeji et al., 1996). Body
temperature is one of the indicators of good health in animal. Its variation above and below
normal is a measure of the animal ability to resist stress factors of the environment. Goat
have a rectal temperature of 390C (Joan, 1999) ranging between 38.7 and 40.8 0C for West
African Dwarf goats. Fasoro (1990) reported that rectal temperature is between 39 and 39.20C
for Red Sokoto goats. Cold environment lowers the core temperature and thereby causing
change in temperature, pulse and respiratory rate have been frequently used as indices of
physiology adaptability to tropical environment. This has been used for heat tolerance or
heat stress index (Oladimeji et al., 1996).
Rectal temperature is usually measured with the aid of a digital or traditional glass
thermometer. If a glass thermometer is been used it must be shaked properly before starting
so that it would read accurately. The procedure for taking rectal temperature includes:
Immobilizing the animal
Lubricate the thermometer
Insert the thermometer a few inches into the goats rectum.
Hold the thermometer in place for at least two minutes.
Slowly remove the thermometer.
Read and record the temperature.
Clean the thermometer with alcohol and cotton ball (www.dummies.com).
2.6 HEAT STRESS IN GOATS
The maintenance of productivity is essentially a function of the environment.
Although goats are known to be adapted to harsh environment, their productivity is affected
adversely by extreme climatic condition (Silanikove, 2000). Depression of food intake and
reduction in productivity are commonly observed in heat stress goats. (Lu, 1989). Goats cope
with heat stress in a variety of ways, they may lie on their sides more than usual on a hot day
or hang out under a tree all day and pant lying flat out, they also expose more body surface
area, especially the short-haired parts of the body. When it gets hotter, involuntary functions
kick into high gear. As heat and humidity increases, goats can have serious problems with
thermal stress. High temperatures affect body function in many ways. The hypothalamus
lying at the base of the brain is in charge of balancing the body’s heat loss and gain by
regulating respiration, skin temperature, sweating and muscle tone. Goats get eight times
more relief from the heat by panting than by sweating, so rapid breathing is their primary
form of cooling themselves.
Panting and collapse are the most obvious signs of heat stress, and the rectal
temperature will exceed 40oC. When the weather warms up, animals eat less in an involuntary
effort to reduce body heat, feed and water consumption go down. Animals may reduce water
intake however, they need water to help keep them cooler.
(Thekebun.wordpress.com/2008/02/24/heat-stress-in-goats).
2.7 HOMEOSTASIS
Homeostasis is the is one of the most influential concepts in the history of biology, it
provides a conceptual frame work within which to interprete a wide range of physiological
data. It is the tendency of an organism to regulate or maintain relative internal stability. The
ability of an animal to survive is often stressfull and varying environment directly reflects
their ability to maintain a stable internal environment. Most environment are characterized by
flunctuations in their physical and chemical properties especially temperature. The
environmental changes ranging about an animal exterior would disrupt cellular, tissue and
organ function if not for physiological system that maintain relatively stable conditions
within an animal body tissues. This phenomenon is nearly universal in living systems (David
et al., 2001).
2.7.1 ANIMAL RESPONSE AND ADAPTATION TO DIFFERENT CLIMATES
Adaptation science describe the study of adjustment that are possible in practises or
structure of system in order to adjust to changes. The atmospheric changes causing necessity
of adaptation can include shift in climate, decline in air quality, or changes in UV levels, but
the term adaptation has been more commonly associated with the climate change issues
(Auld et al., 2002). Several traits are used to evaluate physiological adaptation. There is no
agreement between authors on which traits should be used, but the most used include:
respiratory frequency, heart rate, rectal and body surface temperatures as well as cutaneous
evaporation. Other indicators include: volume of air breathed, sweating rate, activity level,
type of shade, ruminal movement frequency, heamatological and other physiological traits
(Silva, 2000; Marai et al., 2007).
The concept of animal adaptation refers to the genetic and physiological changes taking
place in an animal in response to internal and external stimuli. Various forms of adaptation
includes genetic, physiological and morphological adaptation. Genetic adaptation deals with
selection by nature and man, whereas physiological adaptation concerns with changes
occurring within an individual over shorter or longer period. On the other hand the main
morphological adaptations of different farm animals are external insulation such as (coat, fur
thickness, and subcutaneous fat storage in rump or tail (Auld et al., 2002). The type and
colour of coat found is very important for heat resistance (Turner, 1984; Finch et al., 1984). It
is thought that animals with a dark coat, and therefore with greater absorption of thermal
radiation, are more susceptible to heat stress than those with a light coloured coat (Silva,
1998). In the semi-arid tropics heat gain is lower in animals with a dark coat (Robertshaw,
1986). Despite this, according to Cunha et al., (2004), due to simply esthetics on the part of
Santa Ines breeders, the black coated animals are more popular.
Well adapted animals are characterized by maintenance, or minimum production loss
during the stress period, high reproductive efficiency, high disease resistance, longevity and
low mortality rate. When the animal starts to suffer due to heat, food ingestion is reduced and
metabolism slows, causing a hypo-function of the thyroid. This affects growth, reproductive
efficiency, food conversion and milk production, leading to considerable economic losses
(West, 2003).
CHAPTER THREE
3.0 MATERIALS AND METHOD
3.1 EXPERIMENTAL SITE
The study was carried out at the Small Ruminant unit of Directorate of University Farms
(DUFARMS), Federal University of Agriculture Abeokuta for a period of two months.
3.2 EXPERIMENTAL ANIMAL AND MANAGEMENT
A total of 18 West African Dwarf goats of both sexes (11 bucks & 7 does) and coat colour
which includes black (5), brown (5), tarn (5) and white (3) with age range of 6 month to one
year were procured from the local farmers. The animals were quarantined for 28 days before
the commencement of data collection, during the period of adaptation, antibiotics
(oxyteracycline injection L/A and tylosin injecton), multivitamins (vita flash injection),
dewormer (albendalzole) and other medication was administered to the animals, and before
the introducing the animals into their pen disinfestations, fumigation and proper sanitary
measures was done.
3.2.1 FEEDING
The animals were housed separately on the basis of their sex and coat colour, they were fed
with diets containing 50 % Napier grass (Pennisetum purpureum) and 50 % of formulated
concentrates diet. The diet was supplied as hay and concentrate mixture and it was fed at 5 %
of the animal’s body weight. The animals were fed twice daily by providing hay in the
morning and concentrates in the evening. Water was also provided for the animal ad-libitum
and daily routine cleaning was done.
Table 1: Nutrient Composition of Feed (concentrates) fed to experimental animals.
Diets Percentage (%)
Wheat offal 45
Maize 25
Dried Brewer Grain (DBG) 15
Palm Kernel cake (PKC) 10
Oyster shell 2.0
Bone meal 2.0
Salt 1.0
Total 100% .
Calculated Feed Analysis (%DM)
CP 25.35%
FF 7.94%
TDN 67.97%
3.3 MATERIALS
The material used during the course of the experiment includes Cotton wool and methylated
spirit for sterilizing and cleaning the thermometers used in taken readings to prevent
contamination, digital thermometer used for measuring skin and rectal temperature,
stethoscope for measuring the heart rate of the animals and stop watch for counting the
respiratory rate per minutes.
3.4 EXPERIMENTAL METHOD
The animals were housed separately based on their sex to prevent indiscriminate
mating and the animals were paired based on their coat colour in such a way that no two coat
colour were paired together. The animals were housed in two’s and fed together.
Physiological parameters such as heart rate, respiratory rate, skin temperature and respiratory
rate were measured on a daily basis early in the morning at 8.00am . Rectal temperature was
measured using a digital thermometer which was inserted into the lining of the rectum,
respiratory rates was measured by observing the number of flank movement per minutes and
pulse rate was measured with the aid of stethoscope according to Ajala et al., (2000).
3.5 STATISTICAL ANALYSIS
All data generated were subjected to general linear model of statistical software package
(SPSS) and the significant means were separated using Duncan’s multiple range test
(DMRT).
CHAPTER FOUR
4.0 RESULTS
4.1 Effect of sex on physiological parameters: pulse rate, respiratory rate, rectal
temperature and skin temperature of West African Dwarf goat.
Table 2 shows the means and standard error of mean of the effect of sex on the
physiological parameters measured for West African Dwarf goats. The effect of sex was
significantly different (p<0.05) on pulse rate, with the female having the highest pulse rate
(94.96±0.645) and the male animal having (92.48±0.499) beats per minutes respectively.
There was no significant differences (p>0.05) in respiratory rate, rectal temperature and skin
temperature for both male and female goats respectively.
4.1.1 Effect of coat colour on physiological parameters: pulse rate, respiratory rate,
rectal temperature, and skin temperature of (WAD) goat.
Table 3 shows the mean and standard error of mean of the effect of coat colour on the
physiological parameters measured for (WAD) goats.
The variation in coat colours had a significant effect on the physiological parameters
measured. Coat colour had a significant effect on pulse rate, (p<0.05) white coat coloured
goats have the highest value for pulse rate, and it is preceded by black coat, followed by
brown and tarn colour.
Coat colour also had a significant effect on respiratory rate, (p<0.05), with black coat
coloured goats having the highest value (36.72±0.428) flank movement per minutes, followed
by white coat (34.93±0.574) then brown and tarn.
The effects of coat colour on rectal temperature was significant, (p<0.05) with white coat
having the highest value (38.06±0.095), followed by black, tarn and brown coat.
4.1.2 Interactive effect of coat colour and sex on the physiological parameters of (WAD)
goats.
Table 4 shows the interactive effect of coat colour and sex on the physiological
parameters measured for (WAD) goats during the experiment, coat colour and sex had a
significant effect (p<0.05) on pulse rate with female white goat having the highest pulse rate,
(100.79±1.631) beats perminutes followed by the female black goats (96.88±1.153), while
the pulse rate of black, brown and white male goats is similar to each other with male tarn
and female brown goats having the lowest value for pulse rate.
The effect of coat colour and sex was significantly different on respiratory rate, (p<0.05) with
male black goats having the highest value for respiratory rate, (37.43±0.541), followed by
female white goats (36.82±0.937). These value was slightly higher when compared with
other coat colour for both male and female. Also the respiratory rate of tarn and white
coloured male goats was not significantly different (p>0.05) from each other, while the
respiratory rate of black and white female goats was significantly different (p<0.05) to that
brown and tarn females.
However the effect of coat colour and sex was not significant (p>0.05), on rectal temperature
for all the coat colour observed for male goats, but that of the females goats have a significant
effect on rectal temperature with white and black coloured coat having higher value
respectively compare to the males. Skin coat colour and sex had no significant effect on skin
temperature for both male and female goats.
Table 2: The effect of sex on pulse rate, respiratory rate, rectal temperature and skin
temperature
SEX
Parameters Male Female
Pulse Rate (bm-1) 92.48±0.499b 94.96±0.645a
Respiratory Rate 34.16±0.287 33.98±0.371
Rectal Temp (0C) 37.55±0.048 38.09±0.061
Skin Temp (0C) 38.29±0.023 38.52±0.030
a,b Means within the same column with different superscript are significantly (p<0.05) difference.PR = pulse rate (bm-1) , RR= respiratory rate (fm-1), RT= rectal temperature (0C), ST= skin temperature (0C).
Table 3: Effect of Coat Colour on physiological indices of West African Dwarf goats
MEANS ± SEM
Parameters COLOUR
BLACK BROWN TARN WHITE
PR (bm-1) 95.14±0.744ab 91.49±0.744b 91.06±0.744b 97.19±0.099a
RR (fm-1) 36.72±0.428a 32.95±0.428b 31.68±0.428c 34.93±0.574b
RT (0C) 37.82±0.071ab 37.66±0.07b 37.74±0.07ab 38.06±0.095a
ST (0C) 38.43±0.035a 38.21±0.035b 38.43±0.035a 38.54±0.047a
a,b,c Mean in the same column with different superscript are significantly (p<0.05) different.PR= pulse rate (bm-1) , RR= respiratory rate (fm-1), RT= rectal temperature (0C), ST= skin temperature (0C).
Table 4: Interactive effects of Sex and coat colour on physiological indices of West African dwarf goats
Sex
Male
Female
Pa
Black
Brown
Tarn
White
Black
Brown
Tarn
White
PR
93.41±0.942c
93.14±0.942c
89.80±0.942d
93.59±1.153c
96.88±1.153b
89.84±1.153d
92.32±1.153c
100.79±1.631a
RR
37.43
34.09
32.10
33.04
36.02
31.80
31.27
36.82
±0.541a
±0.541b
±0.541b
±0.663b
±0.663a
±0.663c
±0.663c
±0.937a
RT
37.47±0.090b
37.47±0.090b
37.73±0.090b
37.55±0.110b
38.17±0.110a
37.86±0.110b
37.76±0.110b
38.56±0.155a
ST
38.32±0.044
38.15±0.044
38.46±0.044
38.22±0.054
38.55±0.054
38.27±0.054
38.39±0.054
38.87±0.076
abcd, Mean in the same column with different superscript are significantly (p<0.05) different.PR = pulse rate (bm-1) , RR= respiratory rate (fm-1), RT = rectal temperature (0C), ST = skin temperature (0C).
4.2 DICUSSION
The study revealed that the value for pulse rate was higher in female goats (94.96
beats per minute) than in male goats (92.48 beats per minute) which is in line with what was
reported by Oladimeji et al. (1996) and Butswat et al. (2000) that female Yankasa, Uda and
Balami breed of sheep had significantly higher pulse than their male counterpart. But it was
not in line with what was reported by the same author that female sheep have higher value for
respiratory rate, and rectal temperature. The increase in physiological activities observed
(especially for pulse rate) may be due to increased growth rate in female animals that is
usually accompanied by increased physiological activities as they attain puberty and performs
physiological function such as ovulation, lactation, pregnancy and parturition. These series of
physiological activities may result in increase in the physiological parameters especially
pulse rate, this is in support of the result of the study carried out by Imaseun and Alaomaka
(2012). Also the respiratory rate of male and female goats was not significantly different
from each other this is in contrary with what was reported by Adedeji (2012) that there was
significant sex difference on only the respiratory rate with the male having higher count of
breath per minutes. However, female goats were expected to have higher physiological values
due to onset of oestrus and possibly gestation (Butswat et al., 2000).
The effect of coat colour on the physiological parameters measured was significantly
different. This study shows that the means of white and black coloured goats was
significantly different from each other for pulse rate, and both have higher value compare to
others this is support of a research by Adedeji (2012) who reported that black coat coloured
goats have higher value for pulse rate. Also the effect of coat colour on respiratory rate was
significant for black coat colour having the highest mean values compare to white, brown and
tarn respectively. This is in support of what was reported by Adedeji (2012), that goats with
black pigmentation had the highest respiratory rate (RR); Chowdhury et al, (2001) also
reported higher respiratory rate measured for black Bengal goat. The significant mean value
shown by white coloured goats for rectal temperature is in contrary to what was reported by
Adedeji (2012) that white goats had the lowest rectal temperature and pulse rate, high rectal
temperature and pulse rate observed for white coloured goat is an adaptation mechanism that
allow the animal to cope with its environment. Also increase in (RT) occurs only when the
physiological mechanism of the body are non-productive in order to counteract unnecessary
heat load (Saddiqi et al., 2011). Black coloured goats also have similar high value compared
to that of white coloured goats owing to this, the apparent high mean values of respiratory
rate, rectal temperature and pulse rate observed in black goats could be an indication of
higher heat load occasioned by intense solar radiation and dissipation of this heat which result
in increased respiratory rate, increase water consumption and decline in feed intake. Also the
higher value of RT observed for black goats may be due to absorption of solar radiation by
the dark pigment. Thus pigmentation is very essential for the survival of animals in a specific
environment, it acts as a bridge between the animal and the environment, and it is also
responsible for the maintenance of homeostatic conditions within the animal internal
environment. Therefore, coat colour has an adaptive mechanism that helps the animal to
thrive better in a particular environmental condition.
The mean value shows significant effect for the interaction between coat colour and
sex on the physiological parameters measured, Female white goats have the highest pulse
compare to all the male of other coat colours measured. This slightly differs to what was
reported by Adedeji (2012) that black females goat have the highest value for all the
physiological parameters measured for WAD goats. The fact that lighter coat colour animals
were more tolerant to the prevailing environmental conditions is in line with this, female
animals are expected to have increased value for physiological parameters because of various
physiological activities going on within the animals. The pulse rate was also higher for black
goats as reported by Adedeji (2012) this may be due to high heat load. Also the male black
goats have high respiratory rate this is line with what was reported by Adedeji (2012). This is
also in support of what was reported by Habeeb et al. (1992), that respiration rate can be
elevated through heat stress in goats. The higher respiratory rate observed in male goats is
also in agreement with the report of Oladimeji et al. (1996). They reported that male sheep
had higher values over females in all the physiological indices measured including respiratory
rate. Even though, male goats had higher respiratory values than the females, this could not
be unconnected with the fact that male goats exhibit fears and aggressiveness when they see
strangers and this could be noticed in the way they pant. Invariably, this could have
contributed to the values recorded.
CHAPTER FIVE
5.0 CONCLUSION AND RECOMMENDATION
5.1 CONCLUSION
The following conclusion could be infered from the findings of this study that:
Coat colour and sex have significant effect on pulse rate, respiratory rate, rectal
temperature and skin temperature.
The female WAD goats have the higher value for pulse rate.
Brown and tarn coat coloured goats respond less to environmental changes
5.2 RECOMMENDATION
From this study it is recommended that
Proper management condition should be provided when rearing animals to ensure
that normal range of physiological parameters are maintained.
Animals should be reared in environment where they are best adapted to.
Further studies should be carried out on mixed coat colours.
Automated methods should be used in monitoring the physiological response of
animals in case of large herds.
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