LIVESTOCK PRODUCTION III (SELECTION AND BREEDING) AGRICULTURE NOTES
LIVESTOCK PRODUCTION III (SELECTION AND BREEDING)
This topic entails:
Reproduction and reproductive systems
Cattle
Poultry
Selection in cattle ,sheep ,goats ,pigs and camels
Meaning
Factors to consider in selecting a breeding stock
Methods of selection
Mass selection
Contemporary comparison
Progeny testing
Breeding and breeding systems
Identification of livestock on heat/signs of heat
Description of methods used in serving livestock.
Signs of parturition in cattle ,pigs and rabbits
What does the term ‘epistasis’ mean in livestock improvement?
The combination of genes which individually could have been undesirable or inferior. In this way the effect of some recessive genes are masked such that they cannot be expressed.
What is upgrading as used in livestock production?
A type of mating where the female of low grade is mated to a pure bred sire of superior quality
Differentiate between crutching and ringing in livestock management
Crutching is the cutting of wool around the vulva of sheep while ringing is the trimming of wool around the penis sheaths of rams.
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State the gestation period of the following farm animals
a) Pigs
112 – 117 days/3months 3weeks 3days
b) Rabbits
28 – 32 days
c) Cow
270 – 285 days
What is selection in live stock production
It is the process of allowing certain animals to be the parents of the future generations while culling others
State three methods used in selection of livestock
Mass selection
Progeny testing
Contemporary comparison
Outline two characteristics of livestock that are used in mass selection
Age of the animal
Size/weight of an animal
Physiological condition of an animal
Production level of the animal
Give four advantages of contemporary comparison as a method of selection in livestock breeding.
Possible to compare animals of different age groups since heifer locations are used.
It eliminates differences brought about by the environment since average performance of the herd is used
It is possible to make direct comparison of bulls at different A.I centres since environmental differences are removed.
It is accurate.
Give four signs of heat observed on female rabbit
Frequent urination.
Swollen vulva.
The doe throws itself on its side.
She (doe) rubs herself against the wall or any other solid object.
The doe tries to contact other rabbits in the next hutch by peeping through the cage walls.
State four reasons for culling a breeding boar
Boar is infertile/lacks libido
Loss of sight, limb, cannot mate
Old age
Poor health/Perpetual sickness
Reproductive diseases
Boar is too fat and lazy
Develops bad temperament/Aggressiveness/wildness
Avoid inbreeding
Describe five factors to consider when selecting a breeding boar
High libido
Fertile
Free from hereditary defects
High feed conversion ratio
Fast growing rate
Good body conformation
Free from physical defects
Suit environment conditions
Should be mature
Should be healthy
Describe the factors a farmer would consider when selecting a young female pig (gilt) for breeding.
Good body conformation of the gilt.
Lack of physical defects
Have 12-14 teats
Prolificacy of gilt from records of the parent /ancestors
Healthy, without history of many diseases
Fast growth rate/fast maturing
Ability to withstand stresses
Good mothering ability from record of parents
Age
Temperament of behaviour
Adaptability
Define the following terms as used in livestock breeding
Heterosis
Increased vigour/ performance resulting from mating two superior unrelated Breeds
Epistasis
The combination of genes which individually could have been undesirable or inferior. In this way the effect of some recessive genes are masked such that they cannot be expressed.
State two advantages of natural mating
Accurate hence high conception rates.
Less laborious
Useful in silent heat
State three disadvantages of natural methods of mating in cattle breeding
A lot of semen is wasted
High chances of inbreeding
Large males can injure small females
Expensive to transport bull over long distance
May need extra pasture, extra cost/Keeping males increase costs of production
Encourages transmission of breeding diseases
Few cows can be mated by one bull
Keeping breeding records is difficult
Spread of external parasites
Risky to keep aggressive bulls
a) What is out crossing?
Mating unrelated animals within the same breed.
b) Give four disadvantages of outcrossing
Harmful characteristics can be spread quickly by one bull to the offspring the bull sires.
It requires skilled labour
Low chances of conception because semen can die due to problems in storage and transportation/by wrong timing in respect to heat periods.
It requires more labour than natural service i.e. taking the cow to insemination centre and checking for heat signs.
Distinguish between inbreeding and out crossing in livestock production
In breeding is mating closely related animals whereas out crossing is mating animals within the same breed.
Differentiate between out crossing and cross- breeding
Out crossing – Mating of distantly related animals of the same breed.
Cross- breeding – Mating of animals of different breeds.
How does crossbreeding improve livestock production
By concentrating genes from the parents to the offspring’s
State three advantages of cross-breeding in livestock production.
Improves quality of offspring due to heterozygosity
Introduces new genes into the herd
Offsprings perform better than parents
Offsprings combine traits from parents leading to high performance
A quick method of producing the required animal
Offsprings can adapt well to different environments.
Outline ten factors considered when selecting dairy cattle for breeding
age-young animals have longer productive live and are more productive and economical to keep than old animals
level of performance-animals with highest production level be kept
health-consider animals which are less susceptive to disease
body confirmation go for ones well people dairy characteristics
temperature/behaviour select only decline animals which are easy to handle mothering ability
adaptable under suitability to the environment
prolificacy- ability to give birth to many off springs at a time
physical defects
quality of products
Describe the factors to consider when selecting a breeding stock.
Adaptability of breed to climate or area/ local ecological conditions
Production level – use the production level record of the parents and other contemporaries.
Physical fitness – select animals without any defects like extra teats for dairy animals.
Health – select disease free animals because their health determines their fertility, longevity and fecundity.
Body conformation to type of livestock. For example, for dairy cows, select those with wedge shaped body, well sprung ribs, well set hind quarters and large udder.
Temperament – the selected animals should be docile.
Quality of products-select animals with good quality product
Mothering ability incase of females – select animals with good instinct of taking care of their young ones up to weaning.
Prolifically – is used to denote whether many or few off springs result from a given mating or from a certain individual female during its lifetime.
Breeding efficiency – measures the reproducing ability of an adult animal. The breeding efficiency depends on the number of services per conception, the percentage of non-returns, length of the calving interval and pregnancy period
Fertility – should be fertile
Offspring performance should be good
Age of animal – young not given birth more than 3 times
Disease resistance
Name the type of breeding system represented below
Ayrshire sire x Boran Dam F1 heifer x Hereford
Upgrading/ grading up
State two reasons for breeding livestock.
Introduces new genes hence increasing productivity
For economic reasons; livestock with high growth rates mature faster thus cheap to produce.
Expands inherited potential of the animal.
Satisfy consumers’ taste
Overcome production problems caused by environment such as diseases, pests and adverse climatic conditions
State two signs of farrowing in pigs.
Enlargement of vulva
Loss of appetite
Restlessness
Slackening of muscles on each side of the tail
Udder and teats become enlarged
Presence of milk in teats
Sow collects litter at one corner to build a nest.
Describe the procedure of embryo transplant using non-surgical method
Remove embryo by flooding the uterus with a liquid media
Massage the uterus to dislodge the embryo the uterine lumen to flow out with the solution
Withdraw solution containing the uterus using a tube to a syringe
Syringe taken to the lab where the fertilized ova are selected and separated under high powered microscope
Recipient cow is then restrained anaesthetized and shaved on the area of operation
Incision made in the left flank to allow horn of uterus to be pulled out
Fertilized ovum inserted into the uterus using a pipette or syringe, through the tiny hole in the uterine wall
Pipette checked under microscope to ensure that the transplant is complete
Uterine horn retracted to its position
The diagram below illustrates the reproductive system of a farm animal. Study it and answer the questions that follow
Name the parts labeled A, B, C and D
A- Oviduct B-Ovary
C- Uterus D- Vagina
State the functions of the parts labeled A and B
A-Passage of ova / female sex cells
-Site of fertilization
B-Production of ova
-Production of female sex hormones
c) Give four signs of Oestrus in cows
Restlessness
Frequent mooing /bellowing
Frequent urination
Jelly-like mucus discharge from vulva
Mounting other animals
Stands still when mounted
Loss of appetite
Drop in milk production
Give two signs that would show that a doe is just about to give birth.
Plucking off fur to line up the nest
Making nest
Give the breeding system involved in each of the following cases
(a) Friesian sire mated with Ayrshire dam.
Cross breeding
(b) Friesian sire (father) mated with Friesian dam (daughter)
Inbreeding
a) What is hybrid vigour?
Improved performance resulting from mating two unrelated superior breeds
(b) Give three ways in which an animal will express hybrid vigour
Increase in growth rate
Increase in production
Increased fertility
Improved body conformation
Study the diagram of an oviduct of a hen and answer questions that follow:
Name the parts marked A, B, C, and E.
A- Ovary
B- Infundibulum/oviduct/fallopian tube
C- Magnum
E- Shell gland/uterus
b) Describe two changes that occur on the yolk from part B to E.
B-(Infundibulum)
Fertilization occurs here
Addition of Chalaza
C-(Magnum)
Addition of albumen
Addition of water and salts
D-(Isthmus)
Addition of Albumen
Addition of water minerals and vitamins
Formation of shell membranes
E-(Shell gland/ uterus)
Addition of water and salts
Shell pigments are added
Formation of egg shell
c) Give two functions of isthmus in female bird
Shell membranes formed/ determines shape of egg
Water mineral salts and vitamins added
State four disadvantages of inbreeding
Leads to decline in fertility of animals
Leads to high rate of prenatal mortality/Increase embryonic mortality/abortion
Reduces disease resistance ability
Increase in embryo mortality / abortion
Reduce vigour / becomes weak/ heterosis
Reduce yield / performance
Differentiate between artificial insemination and embryo transplant
I is the introduction of semen into the female reproductive tract by hand using syringes or tubes while Embryo transplant is where ova (eggs) are harvested from a female animal (donor) fertilized in test tubes and then embryo’s that develop are transplanted into foster mothers(recipient)
a) Define Raddling in sheep management
Is the practice of fitting the rams with breeding chutes on the underside which are painted with colours during breeding
b) State two reasons for raddling.
Used to identify rams which have mated.
Helps to identify ewes that have been mated.
Helps to identify fertile rams.
The diagram below shows reproductive system of a hen. Study it and answer the Questions that follow.
a) State one component added to the egg during formation at regions A and B.
A-Chalazae are added
B-shell is added round the egg.
b) What happened if blood spot drops at the part labelled A.
The blood spot will be added to the egg contents during egg formation.
Give two advantage of embryo transplant in livestock breeding
Improves performance / production
Stimulates milk production in a female that was not ready to produce milk.
Easier to transplant embryos in test tube than the whole animal
Embryo can be stored for a long time awaiting a recipient female
Highly productive female animal can be spread over a large area to benefit many farmers
It is possible to implant embryo from a high quality female to less valuable female and hence improve the performance of the offspring
Calf produced gains passive immunity to local diseases from mother.
List three disadvantages of embryo transplant.
Expensive
Requires highly skilled labour
Require special equipment for fertilization & storage
If the uterus of the animals to receive the embryo is not ready implantation will not occur
A cow gives birth to two offsprings in a period of three years. One offspring is a male named Chemosi and another, female named Lelkina. Two years later Chemosi is mated to Lelkina and another offspring, called Daisy is given birth to.
i) Identify the specific system of breeding between Chemosi and Lelkina.
Inbreeding
(ii) Give four disadvantages of such a system of breeding)
Leads to loss of hybrid vigour
May lead to decline in fertility leading to species extinction
Reduce disease resistance.
Bring reduction in performance.
Leads to high rate of pre-natal mortality/High embryonic mortality.
Differentiate between the terms tupping and crutching as used in sheep management
a)Tupping
Removal of wool around the anus, vulva and udder in preparation for lambing
b) Crutching
Removal of dung massed wool around the anus and vulva in preparation for mating.
State four signs of infertility in a dairy cow
No heat signs
The cow has irregular heat period
The cow has prolonged heat signs
It produces abnormal discharges from the reproductive organs
The cow does not conceive after several services.
Give four causes of infertility in cattle
Damaged uterus due to abortion, injury, infection.
Infections by venereal diseases e.g. virginities, brucellosis
Retained placenta after birth causing infections
Blocked fallopian tubes due to infections.
Lack of essential nutrients/elements e.g. Vitamin E, manganese, selenium
Freemartin, a heifer born twin with a bull is 90% infertile.
Hormonal failure/imbalance.
Give two reasons why teaser rams are introduced to a flock of ewes some weeks before tupping
To induce heat /synchronize ovulation in ewes
To accelerate ovulation
Suggest two factors that can lead to conception failure after the females have been served.
Poor nutrition (flushing)
Poor timing of service
Infertility of either bull or the female
Give four disadvantages of using artificial insemination (A.I) in serving a cow
Collecting / storing and administering semen is labour intensive and time consuming.
Require skill / trained personnel
Not feasible in areas not easily accessible by A.I offices.
Poor detection of heat / oestrus period may lead to failure in administering A.I
Harmful traits/diseases can spread fast.
Low chances of conception due to poor timing/death of sperms.
Give two reasons why artificial insemination is not popularly used as a mating system in pigs
Difficult to note heat signs
It requires long time for maximum fertilization of eggs
Difficult to preserve the semen while viable for long
Describe five advantages of artificial insemination in livestock breeding.
Semen of one bull can serve many cows
Controls the transmission of breeding diseases
Eliminates fighting and injury during mating
Eliminates the expenses of keeping a bull as regards feed drugs
Semen can be stored for long period of time.
controls unwanted breeding on the farm eg inbreeding
enables correct keeping of breeding records on the farm
An effective research tool on the farm.
Small scale farmers who cannot afford superior bulls get their cows served at low costs.
Eliminates problems of bull specializing in one cow only .
Timely breeding.
State four desirable characteristics to be considered when selecting heifer for milk production
Docile/mild temperament
High milk production records from ancestors
Free from physical deformities
Good health
Good size/weight for the breed.
State two reasons for culling breeding sows.
old age
low fertility/production
difficulty in furrowing
Less milk/Agalactic
When offspring shows bad traits e.g. umbilical hernia, atrophic rhinitis.
Poor health/ chronic diseases/ serious injuries.
Poor mothering ability e.g. lying on young ones, refusing to suckle the young one(s)
Give four methods that can be used to improve local breeds of livestock.
Cross breeding
Back crossing
Grading up/ up grading
Control of parasites and diseases
Proper feeding of animals
Proper housing
State four signs of heat in pigs(sow)
Restlessness
Frequent urination
Swelling and reddening of vulva
Clear or slimy mucus discharge from vulva
Responds positively to riding test.
Frequent mounting others.
Sow mounts other pigs and allows others to amount it
Loss of appetite
Produces grunting noise
Sow tries to reach out to other pigs in adjacent pens.
Explain the meaning of the following terms.
Epistasis-The combination of genes which individually could have been undesirable or inferior. In this way the effect of some recessive genes are masked such that they cannot be expressed.
(b) Hybrid vigour –is the increased ability and performance of the offspring above the average of the two unrelated parents or one of the parents.
State three signs of parturition in cows.
Restlessness/ Cow lies down frequently
Loss of appetite
Enlargement of udder
Enlargement of vulva/ Swollen vulva
Cow isolates herself from the rest of the herd.
Pelvic muscles relax.
Mucous discharge from the vulva
Presence of thick milk if teats are squeezed/pressed/ Presence of Colostrum in teats
Relaxation of pelvic muscles/Slackening of pelvic muscles or relaxing of hip muscles
Full and distended udder
Water bag appears which may burst.
Outline four objectives of livestock breeders
Increase resistance to diseases
Increase tolerance to pests
Adapt animal to local environment.
Increase productivity
Increase prolificacy
Enhance good mothering ability
Maintain uniformity in colour.
State two factors considered during tupping
Size of sire and dam.
Health of males and females
Ratio of sire to dam/females to males
The diagram below shows a reproductive system of a bull. Study it and answer the questions that follow.
a) Identify the parts labeled M, N, O and P
M – Scrotum
N – Testes
O-Urethra
P – Seminal vesicles
b) State the function of the part labeled L
Carries the sperm to the urethra.
If a dairy cow is noticed to be showing first signs of heat at 6.00am, what time should it be inseminated?
From 12.00 to midnight (any time between 12.00 and midnight.)
List six causes of sterility in dairy cows.
Freemartinism
Nutrient deficiency
Damaged uterus
Retained placenta
Blocked fallopian tubes
Diseases of reproductive organs.
Outline two reasons for adopting proper breeding programmes by farmers.
To prevent transfer of diseases
For high quality offsprings and/ or products
What is the duration of oestrus cycle in a cow?
18- 22 days
Study the diagrammatic representation of breeding programme below occurring in two stages;
a) Identify the specific breeding system at stages I and II.
Stage 1- upgrading
Stage – Inbreeding
b) State two disadvantages of the breeding system represented by stage II
Bad traits may be expressed/ lowering production or vigour
High rate of pre -natal mortality
Reduction in performance
Decline in fertility / species extinction
What term is used to refer to the condition during calving in which the hind legs come out first?
Breech/rear presentation/malpresentation.
Study the illustrations of parturition F and G below and answer the questions that follow
(a) Which of the foetus is in the correct position of parturition?
G
(b) Name the type of parturition given to foetus F and G above.
F= Breech / Rear presentation
G= Normal presentation
(c) What name is given to the type of parturition when the foetus is born dead?
Still birth
List two abnormalities which may arise during egg formation
Lack of shell
Soft shelled eggs
Double yoked eggs
Tiny eggs
Give two function of testis in the reproductive system of male cattle.
Produce the spermatozoa
Produce male sex hormones
What is the function of chalazae in a formed poultry egg?
Chalaza holds the egg yolk in position
State two methods of service in livestock
Natural mating
Artificial Insemination.
Distinguish between Caponization and embryo transplant as used in livestock breeding
Caponization: It is the act of making male birds loses their male characteristics. While Embryo transplant: ova are harvested from high quality animals, fertilized in test tubes and then embryos that develop are implanted into foster mother.
The illustration below shows a livestock equipment. Study it and answer the questions that follow
a) Identify the equipment
Artificial vagina
b) Identify parts labelled L and K
L – warm water
K- Collected semen
Diagram below illustrate livestock production tool
(a) What is the suitable name of the livestock production tool above?
Elastrator and rubber ring
(b) State one function of the above tool
Castration
Docking
Dehorning
Differentiate between dominant gene and a recessive gene
Dominant gene is a breeding characteristic/trait while recessive gene is the trait suppressed by another characteristics/traits
State four management practices that should be carried out during the mating season in sheep
Crutching of ewes
Ringing the rams
Raddling of rams
Flushing i.e. giving nutritious food during mating.
The illustration below show different livestock families Use it to answer the questions that follow
Zebu Family Hereford Family
a) Identify the breeding system between
(i) C and A
Close breeding
(ii) D and T
(ii) Cross breeding
(b) State two advantage of the breeding system identified in a (ii) above
Offsprings exhibit hybrid vigour
Introduces new genes in the herd
Decline infertility
High rate of offspring mortality
(c) Why is the breeding system identified in a(i) not recommended in dairy cattle
Leads to loss of vigour
Explain three methods of collecting bull’s semen.
Use of artificial vagina
Use of breeders bag
Recovery of semen from the female vagina soon after natural mating
Electrical stimulation of the bull to ejaculate
By the massage method of the bull to ejaculate
Describe ten methods of pregnancy diagnosis in cattle
Absence of heat periods
Decline in milk output in lactating cows
Vaginal temperature raising slightly
Feel method, application of pressure on the right flank of the foetus.
Thick milk secretion in teats
Change in density of cervical mucus drastically.
Change in cervical pH drastically
Rectal palpation to feel minute movements of the foetus.
Blood analysis for the presence of pregnancy hormones.
Name three systems of breeding used to improve livestock.
Upgrading
Inbreeding
Out crossing
Cross breeding
Explain the following terms as used in livestock production
Embryo transfer
Method of breeding which involve removal of ova from a superior animal, fertilize externally in a test tube then transfer to a foster mother which carry pregnancy to term
Artificial insemination
Introduction of semen in to the females reproductive system by use of a tube
Line breeding
Is mating of distantly related animals but within the same breed
Cross breeding
Mating of animals belonging to different breeds e.g. Friesian bull and jersey cow
Up-grading
Is the mating of high grade bull/sire to a low grade cow/dam
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