Transcript Environmental Impact Assessment (EIA)

LIVESTOCK PRODUCTION
LECTURE 8
INTRODUTION
 Domestication
of wild animals enabled
people to:
 Produce
food i.e. meat, milk, cheese and
other dairy products, eggs etc.
 Produce leather for clothing, shoes, bags
and other by-products for the manufacture
of glues, drugs, fertilizers etc.
 Provide means of transport e.g. camels,
donkeys and horses.
 Provide farm power e.g. water buffaloes
and bullocks for ploughing fields.
Classification of Farm Animals
 Animals
can be classified either
 Scientifically
or
 According to their nutrition (feeding habits)
 Scientifically
 All
common farm animals of the tropics
except poultry and rabbits belong to the
class Mammalia and
 order Artiodactyla.

 Cattle,
sheep and goats belong to the
family Bovidae whereas pigs belong to the
family Suidae.
Classification of Farm Animals
 Cattle
belong to the Bos genus, the sheep
belong the Ovis genus, the Goats to Capra
genus and the pigs to Suis genus.
 The domestic rabbit belongs to the family
Leporidae and is derived from the species
Oryctolagus cuniculus.
 According
to their nutrition farm animals
can be grouped into
 Ruminants
 Non-Ruminants
 Herbivores
Ruminants
 These
are animals with a complex
stomach of four compartments.
 One compartment is the rumen where
the food that has just been eaten is
temporarily stored.
 The cellulose in the plant cell walls is
digested in the rumen by the rumen
bacteria.
 From the rumen the food is passed into
another compartment known as the
reticulum.
Ruminants
 From
the reticulum, food is regurgitated
back into the mouth where more
chewing swallowing of the food occurs
again.
 This process is referred to as chewing
the cud.
 The other two compartments in which
further digestion takes place are the
omasum and abomasum
Non-ruminants
 These
are animals with one stomach
compartment and omnivorous habits
 They include the pigs and poultry.
 Poultry describes all forms of
domesticated birds including chickens,
turkey, ducks, guinea fowl, pea fowl,
pigeons, gees and ostriches.
 Pigs are particularly important in nonmoslem countries where they are
increasingly being reared under
intensive conditions.
Herbivores
 These
are non-ruminant plant eaters
 They include
 Rabbits,
 Guinea
pigs,
 Larger farm animals such as
Camels
 Horses
 Donkeys
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The larger animals are used mainly for
transportation and as farm power.
Types and Classes of
Domesticated cattle

Cattle are categorized as
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Beef Cattle
Dairy Cattle
Dual purpose cattle
Draught Cattle
Beef Cattle
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These cattle are best suited for beef production
having a great width and depth of body.
The udder is usually poorly developed and little
milk is produced.
These animals are efficient in the conversion of
feed into high quality beef for human consumption.
Types and Classes of
Domesticated cattle

Dairy Cattle
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Have a lean angular frame with a well-developed
mammary system, moderate girth and deep belly.
One of the most important characteristic of dairy
cattle is good temperament.
Dual purpose cattle

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These are intermediate between beef and dairy
cattle in conformation and performance.
Many indigenous breeds in the tropics are used as
beef, dairy and draught animals.
Types and Classes of
Domesticated cattle
 Draught
 These
Cattle
are characterized by great size and
length of body and strength given by their
rugged form.
 In many parts of the tropics, oxen are still
used as a source of power for tilling the
land.
Adaptation of Livestock to
Tropical Environments
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Early attempts to export temperate breeds of
livestock met with dismal success.
After a relatively short time in the tropics, the
productivity of many breeds of exotic stock
decreased, their condition deteriorated and they
became susceptible to tropical diseases.
In the recent years agricultural scientists have
devoted attention to the subject of adaptation of
livestock to hot climates.
Thus the environmental physiology of farm livestock,
the effects of solar radiation and heat stress on their
productivity in tropical and subtropical areas have
been well documented.
Adaptation of Livestock to
Tropical Environments

The basic principles of thermal adaptation are
common to all vertebrates.
 However different types of external covering
(hair, wool, feathers and bristles) and the
different types of underlying skin structure,
give rise to variations in the mechanism of
heat loss and the maintenance homeothermy
(maintenance of an almost constant internal
body temperature).
Effects of Heat on Tropical
Livestock
A
temperate animal taken to a hot
climate is affected in two distinct ways.
 Directly
by the influence of high
temperature and intense radiation and
possibly humidity on the animal itself
 Indirectly by the effect of heat on the
animal’s environment including natural
feed supply.
Direct Effects of Heat

Every vertebrate animal has a particular
range of environmental temperature to which
it is adapted and in which it is able to live
most efficiently at minimal metabolic rate.
 This is what is referred to as the comfort
zone.
 When animals are kept at temperatures
below or above their comfort zones their
metabolic rate is increased, either to keep the
animal warm or to assist in heat dissipation.
Direct Effects of Heat

Evaporative losses of water from the body
surfaces are the most fundamental processes
concerned with heat regulation.
 At low environmental temperatures, nonevaporative cooling (i.e. loss of heat due to
conduction, convection and radiation) is
responsible for more heat loss than
evaporative cooling.
 As the environmental temperature rises, the
proportion of evaporative cooling rises and
the proportion of non-evaporative cooling
falls.
Direct Effects of Heat

The principal effect of sweating is to limit the
rise in skin temperature.
 Since skin temperature largely governs
respiration rate a high sweating rate will be
associated with a relatively low respiration
rate.
 The major ways in which animals adapt to
tropical heat include:
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Heat tolerance
Coat characteristics
Skin pigmentation.
Heat tolerance
A
heat tolerant animal is one that has a
high efficiency of energy utilization and
allows productive processes to continue
at high level without the production of
excessive amounts of heat.
 Heat tolerance index is used to describe
the heat tolerance range of different
animal species.
Coat characteristics

The role played by the hair coat in thermal
balance in a hot environment is twofold:
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It affords a certain degree of protection against
radiant heat from the sun.
It interferes with the dissipation of heat from the
animals body surface.
The most important characteristics include:
Coat color
Coat Texture
Skin pigmentation
Coat characteristics

Coat colour is important in reflecting or
absorbing solar radiation.
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Hair fibres which are light in colour reflect more
solar radiation than hairs which are dark.
The amount of sunlight reflected can be as much
as 50% in the case of a white-haired animal, but
considerably less with a dark-coloured animal.
The coat colour is of much importance during
periods of high light intensity (summer) than
during periods of low light intensity (winter).
Coat characteristics

Coat Texture affects the mean absorption
coefficient of animals.
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The rectal temperatures and respiration rates of
Woolly-coated animals are invariably higher than
those of animals with fine, glossy coats.
The nature of the hair has a bearing on the
insulative properties of the coat.
Skin pigmentation

A pigmented skin is most desirable in the tropics
since it is less susceptible to sunburn and
photosensitivity disorders.
Indirect Effects
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The most important indirect effect of climate on
tropical livestock is that associated with water
requirement and feed intake.
The quantity and quality of feed on offer to tropical
livestock is primarily dependent upon the climatic
factors influencing, and possibly limiting, plant
growth.
The second most important indirect effect of climate
on farm animals is its influence on the distribution of
the major pests and diseases and the arthropod
vectors which are responsible for their spread.

For example, the distribution of Tsetse fly is directly related
to the presence or absence of suitable breeding sites, and
these are themselves influenced by the climate of that
region.
Animal Feeding/Nutrition

Animals require feed rations that are
complete and balanced nutritionally.
 Each species and category of animal within a
species has different nutritional requirements
that must be calculated with care to ensure
maximum productivity.
 The two main types of feedstuffs are

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Roughage, with high crude fibre content, and
Concentrates with low crude fibre content.
Roughage

Roughage is fed fresh or in the form of hay or
silage to supply some protein, energy,
vitamins and minerals.
 The commonly used grasses are Guinea
grass, Elephant grass and giant star grass.
 Maize, millet and sorghum are usually cut for
making silage.
 The common legumes include clover.
 Concentrate feeds provide energy and
protein needs.
Forage Conservation

The surplus grasses and cultivated crops
produced during the growing season can be
conserved a hay or silage to be utilized
during the dry season when available grass
becomes fibrous and unpalatable.
 Hay
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Forages are cut and dried naturally, by air and sun
drying, or artificially.
The forage is cut at sufficiently early stage of
maturity to ensure nutritional excellence.
Drying usually lowers the water content below
25% so that the hay can be stored without
becoming mouldy or fermented.
Forage Conservation
 Hay
 Properly
cured hay is close to the original
forage in nutritional value.
 Silage
 Grasses
and cultivated crops such as
maize, sorghum and millet are conserved
as silage by chopping them into pieces,
placing them in a silo and compressing
them sufficiently to exclude most of the air.
 Fermentation of soluble carbohydrates
takes place producing organic acids,
mainly lactic acid, with some ethanoic acid.
Forage Conservation
 Silage
 The
low pH of the mass prevents growth of
undesirable bacteria that cause
putrefaction (making it to go bad).
 Fermentation ceases after sufficient acid
has been produced.
 The silage will keep for a long time with
little change if stored in airtight bins and
protected from rainwater.
Animal Health

Animal diseases and disorders cause
considerable losses, which include:
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Death of the animals
Increased cost of production
Lowered quality of meat, hides and skins
Greatly reduced efficiency of animal production
Some diseases and parasites are transmitted
from animals to humans by contact,
contamination of water or when a person eats
food products from a diseased animal.
Signs of ill health in farm
animals
 Disease
is any condition of the animal,
which differs from normal health.
 All the vital processes of feeding,
digestion, respiration, blood circulation
movement and all related activities
function satisfactorily in healthy animals.
 Departures from some or all of these
processes indicate ill health.
Signs of ill health in farm animals
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Signs of ill health in farm animals include:
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Dullness.
Restlessness or nervousness.
Loss of appetite or complete avoidance of feeding
Indiscriminate feeding
Severe loss of body mass in severe cases
Uncoordinated movement
Death
Signs of Good Health
 The
state of health of an animal can be
assessed from observations on:
 Pulse
Rate
 Body temperature
 Body Conformation
 Condition of skin or coat
 Visible mucous membranes
 Feeding habits
Signs of Good Health
 Pulse
 This
Rate
is the rate and force of blood passing
through the blood vessels per minute.
 This reflects the heart beat.
 The normal pulse rates per minute for
cattle is 50-70, for the horse is 28-42 and
for the sheep is 68-90.
 When the pulse rate is outside the normal
range, unless it can be explained
physiologically (e.g. exercises increase
rate) ill health may be suspected.
Signs of Good Health

Body temperature
 Normal body temperatures in °C are:
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Cattle 37.6-39
Horse 37.5-38.3
Sheep 38.3-39.3
Pig 38.3-39.3
Any change in temperature above or below
the normal range may indicate ill health.
Signs of Good Health
 Body
Conformation
 Excessive fatness may result from
overfeeding or disease while leanness
or emaciation may be a result of underfeeding, starvation or disease.
 A normal animal usually shows the
proportions or body organs and tissues
characteristics of the breed or strain of
the animal.
Signs of Good Health
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Condition of skin or coat
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The skin of a healthy a normal is usually smooth
and slips back easily when pulled.
The hair is bright, clean and unruffled.
Extremely dry hair or staring coat where the hair
sticks up, are symptoms of ill heath.
Excessive sweating causes the hair to form a mat
on the skin and indicates ill health it is not a result
of exercise.
Similarly, loss of hair, abnormal out-growths or
swellings of the skin, eruptions and boils,
presence of parasites on or under the skin of
animals are all signs of ill-health.
Signs of Good Health
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Visible mucous membranes
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The inside linings of the eyelids, nose, mouth and
the external urinogenital tract of normal animals
are usually moist and pinkish.
When an animal is ill, these linings may appear
bright red or pale and anaemic or yellowish or
bluish depending on the type of disease from
which the animal is suffering.
Signs of Good Health
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Feeding habits
Healthy animals consume enough food when
available according to nutritional needs.
 A sick animal may develop abnormal appetite
for non-feed materials and eats anything
indiscriminately.
 Healthy ruminants chew the cud in between
feeding but sick animals do not and in some
cases the animal may vomit the ingested
feed.
 The consistency, texture, colour, smell and
frequency of defecation or urination may also
indicate ill health.
Causes Diseases and
Disorders

Animal diseases and disorders can be
caused by living organisms such as bacteria,
fungi, viruses, nematodes and trematodes
(helminthes), ticks, lice and flies and by nonliving substances such as chemical poisons.
 Other causes include insufficient or poorquality feed as well as deficiencies of
nutrients such as carbohydrates, proteins,
mineral elements and vitamins.
 Some diseases or disorders are due to one or
more of these causes.
Causes Diseases and
Disorders
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Poorly fed animals are more prone to succumb to
attacks by living organism.
Under the traditional system of animal husbandry in
the tropics, animals are poorly fed.
A cause that excites a disease is always directly
associated with it whereas a predisposing cause
reduces an animal’s resistance to the exciting cause.
The causes can be categorized as:
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Physical causes
Mechanical causes
Chemical causes
Biological causes
Causes Diseases and
Disorders
 Physical
causes
 Abnormal
ambient temperatures are
important although in the tropics it does not
fluctuate so much.
 Animals imported from temperate regions
are most affected.
Causes Diseases and
Disorders
 Mechanical
 Pressure
causes
on body tissues from tumours or
parasites, polyps (small growths) in the
nose and urinogenital system are often
disabling especially where they affect a
vital organ such as the brain or liver.
 Obstruction of the air and food passages
by feed or other materials or strictures of
the orifices caused by contraction of the
muscle or coats are other common
mechanical problems.
Causes Diseases and
Disorders
 Chemical
 Retained
causes
waste products of body
metabolism such as urea, other
nitrogenous compounds or excessive
carbodioxide can cause illness as well as
poisonous substances such as acids and
caustic alkalis.
 Heavy metals and animal toxins may be
inhaled, ingested or taken in through the
skin.
Causes Diseases and
Disorders

Biological causes
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A large number of parasitic bacteria, fungi,
viruses, protozoa, helminthes (worms) insects and
ticks actively invade animal tissues and organs.
These invasions result in localized or generalized
disease conditions that may be fatal in very severe
cases.
Feeding animals on unbalanced feed or dirty
water can cause nutritional deficiencies or
introduce disease-causing organisms respectively.
Diagnosis of Disease

This is normally done by veterinarians
through a combination of physical
examination, observation of clinical
symptoms and chemical and microbiological
tests in the laboratory.
 The results give a basis for the application of
preventive and curative measures to combat
or control the disease.
 The carcass of a dead animal is examined for
any signs of lesions of the killing disease in a
post-mortem examination.
Transmission of Disease

Diseases are transmitted from one animal to another
when pathogens escape from an infected animal and
spread to healthy animals.
 Many disease-causing organisms are destroyed by
the defensive mechanisms of the host,
 others are eliminated in its secretions and discharges
and may invade other animals or re-infect the same
animal.
 Thus an animal that dies from an infective disease
should be properly disposed of by burning or burying
the carcass deep in the soil.
 This ensures that the pathogens are destroyed and
do not spread the infection.
Transmission of Disease

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In some cases the pathogen and its host can co-exist
so that the pathogen does not produce disease
symptoms and the animal’s body does not destroy
the pathogen.
Predisposing factors such as poor nutrition or intercurrent diseases can upset the balance and allow the
pathogen to become infective.
The animal then develops the disease symptoms.
High levels of nutrition, management and sanitation
help animals to resist invading pathogens.
Sources of Infection

The ways by which pathogens reach their hosts
include:
 Direct or immediate contact with other diseased
animals resulting in the transfer of the disease. Skin
diseases and some venereal diseases are
transferred in this way.
 Indirect contact with objects such as dirty utensils,
vehicles used to transport sick animals or railings in
animal houses which may carry over pathogenic
organisms from sick to healthy animals.
 Contact with symptomless carriers.
 Soil-inhabiting spores of some bacteria invade
animals through wounds e.g. tetanus, anthrax and
clostridial infections are often picked up by grazing or
trekking animals.
Sources of Infection

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Ingestion of contaminated feed.
Airborne infection in overcrowded housing e.g. most
respiratory diseases caused by bacteria, fungi or
viruses.
Blood-sucking and biting flies, fleas, lice and ticks
transmit disease organisms through their bites. E.g.
Trypanosomiasis, tick fever and some filarial
infections.
Condition loss due to stress.

Some bacteria live in mucous membranes of animals without
causing disease but in cases of stress, the organism
becomes pathogenic.
Routes of infection

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Main route of entry of parasites and pathogens into
an animal’s body is through the organs and tissues of
the animal including the alimentary canal,
urinogenital organs, eyes, nose, and skin.
The skin, which serves as a protective coat over the
body organs and tissues, may become a route of
entry for pathogens wherever it is mechanically
damaged or weakened.

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Many fleas, ticks and lice attach themselves directly to the
skin or merely live on the surface of the skin protected by the
hair or the feathers. In sucking blood or biting the animal,
they inject pathogens.
Pre-natal and post-natal infections of young animals
may occur through the placenta or poorly managed
umbilical cords.
Routes of infection
 Some
pathogens of poultry can be
transmitted through the egg from an
infected hen.
 The respiratory tract, conjuctiva and
mammary glands are also routes of
infection.
Disease Course

After infection and before disease symptoms occur
there is usually an incubation period.
 This is the time lag between the entry of the infective
organism into the animal and the outward expression
of signs of the disease.
 During this period the animal appears normal but it
can infect other animals.
 Once the symptoms of a disease appear, the disease
may progress rapidly into an acute condition, which
may progress to death or recovery.
 In chronic cases, the disease persists for a long time
and may or may not cause death of the animal.
 If the animal contracts another disease during this
time, it may die after prolonged suffering and
extensive loss of condition.
Defense against Disease

Normal animals protect themselves against disease
by:
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Primary defensive mechanism which hinder or prevent the
entry of pathogens
Secondary defensive mechanism which attack the
pathogens which enter the body.
The secondary defensive mechanism either prevents
multiplication and spread of the pathogen in the
animal’s body or inactive toxins produced by
pathogen.
The white blood cells can produce antitoxins against
specific pathogenic secretions.
This is what is referred to as immunity
Defense against Disease

Any foreign protein (antigen) entering an
animal’s blood makes the white blood cells
produce antibodies.
 These chemicals attack the antigen and
immobilize or destroy it.
 The types of immunity include:
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Natural immunity
Artificial immunity
Natural immunity

The animal’s white blood cells have the ability to
produce antibodies to some antigens before they
are exposed to infection by those antigens.
Defense against Disease
 Natural
immunity may be
 Inherited
 Passively
acquired through the colostrum
and milk of the mother
 Actively acquired after infection – whether
or not the animal exhibits symptoms of the
disease.
Defense against Disease

Artificial immunity

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Active artificial immunity is achieved by the
injection of a non-pathogenic attenuated (reduced
in strength) form or a small amount of the living
pathogenic organism.
Secretion of antibodies in response confers a
state of immunity, which may be temporary or
permanent.
Usually the process is repeated periodically
to ensure that the immunity does not fade
away.
Defense against Disease
 Passive
artificial immunity is conferred
by injecting serum obtained from an
animal that has recovered from a
disease into another animal that is
susceptible to the same disease.
 The antibodies in the serum confer
immunity to the recipient animal only for
a short time.