Reproduction in farm animals. Reproduction is the process by which off-springs are produced. All farm animals multiply by means of sexual reproduction. It begins with fertilization which is the fusion of male and female gametes to form a zygote. Fertilization takes place internally in the body of the female. The embryo(zygote) formed develops inside body of mother, fed and protected until end of gestation period.
In poultry, the process is different in that eggs are fertilized internally but laid and development of the chick takes place outside during incubation
HOW DOES REPRODUCTION TAKE PLACE THROUGH MATING?
SO WHAT IS MATING? Mating is also called coitus or copulation
Mating is the act in which the private part of the male is inserted into the private part of the female, leading to depositing of spermatozoa in order to cause reproduction to take place in farm animals
(iii) Mating in farm animal may lead to fertilization
reproduction through mating is under the influence of hormone
(v) Mating is necessary before farm animals can reproduce sexually
(vi) For mating to occur, the female animal must be on heat period
(vii) The male organ must be erect before mating can occur in reproduction process
(viii) It takes place when the male mounts the female for sexual copulation
(ix)mating of farm animals leads to the occurrence of depositing of seminal fluid containing spermatozoa which is deposited in the female opening
TYPES OF MATING IN REPRODUCTION IN FARM ANIMALS
(a) Natural mating: This occurs when a male, after identifying a female on heat period will mount on the female for mating the animal. Examples of natural mating are
(i) Flock mating: both male and female animals are allowed to move together and mate freely
(ii) Pen Mating: Very few number of males are kept together with limited number of females so that they can mate any time the female animals is on heat period, e.g four males together with twelve females
(iii) Stud or Hand mating: The males are kept separately to be mated with individual females when on heat period. After mating, the male is taken away artificial mating:
This is called artificial insemination which involves the act of injecting spermatozoa artificially into the female animal on heat period. The reproductive cells are collected from a male animal with desirable characters,. Such spermatozoa are stored at 196oC under liquid nitrogen until it is used
ADVANTAGES OF ARTIFICIAL INSEMINATION DURING REPRODUCTION
(i) It is cheaper to import sperms than to import the male animal
(ii) Sperms collected can be used to fertilize many female animals of various sizes
(iii) It is more economical as it reduces the cost of feeding and managing male animals
(iv) Sperms can be used over a long time even after the death of the male animal
The breeding of animals is under human control, and the breeders decide which individuals shall produce the next generation. The breeder makes a choice.
The breeding of animals is based upon the fact that certain qualities are genetic ,hence valuable qualities are passed on from parents to off -springs. The qualities can be maintained or improved in the next generation.
you can read crop improvement process here
The performance of an animal is influenced by two major factors;
Genetic potential in reproduction using artificial insemination
the following are some of the reasons why artificial insemination is carried out
Feeding,Health, care and the ecological conditions.
The genetic potential of an animal is inherited from its parents.
In selection and breeding animals with superior characteristics are selected and allowed to mate.
In the process they transmit the superior characteristics to their offspring.
When this is done over a long period of time, it results in livestock improvement.
Reproduction and Reproductive Systems of farm animals
Reproduction is the process by which off-springs are produced. All farm animals multiply by means of sexual reproduction.
It begins with fertilization which is the fusion of male and female gametes to form a zygote. Fertilization takes place internally in the body of the female. The embryo(zygote) formed develops inside body of mother, fed and protected until end of gestation period.
In poultry, the process is different in that eggs are fertilized internally but laid and development of the chick takes place outside during incubation.
In both male and female, certain organs are specialized for the process of reproduction.
Some of these organs secret fluids which are necessary for the movement and survival of the gametes(reproductive cells.)
Male Reproductive System (Bull)
The male reproductive organs produce the male gametes,the spermatozoa.
These are introduced into female reproductive system, where they fuse with the sperm to form zygote.
The reproductive system(bull) is composed of the following parts;
i). Testes
ii). Epidermis
iii). Sperm ducts
iv). Accessory glands(Seminal vesicles and prostrate glands)
The testis:
There are two testes hanging loosely between hind legs.
Enclosed by loose skin (scrotum)scrotum regulate temperature of testis for optimum production of sperms.
Produce spermatozoa(sperms)which are stored in coiled tube called epidermis.
Epidermis: Storage of spermatozoa.
Sperm ducts: for reproduction to take place, the following reproductive system must be function effectively
Conveys sperm from the testis and urine through the male organ
sphincter muscles contract to allow each to pass separately.
Seminal vesicles produce fluid called seminal. Seminal carries sperms out of male organ in fluid form.
Seminal fluid contains nutrients to the spermatozoa.
Prostate gland -produce fluid that neutralize the acidic effects of urine in the urethra preventing death of sperms.
Accessory glands: Include seminal vesicles cowpers gland and prostate gland. Urethra: Conveys urine and spermatozoa. One sperm fertilizes ovum
the male reproductive organ
Surrounded by a sheath which is an extension of skin.
It introduces sperms into the female opening of a cow .
It is a copulatory organ, also used for urination.
2. The Female Reproductive System(Cow)
the reproductive system of a cow is composed of;
i). Ovaries
ii). Fallopian tubes
iv).
v). Uterus
Ovaries and fallopian tubes(oviduct)
Two ovaries located in abdomen, left and right. Produce ova/eggs and hormones which control sexual cycle. Oestrogen produced by graafian follicle inside ovary induces oestrus i.e. Heat period so that the cow shows signs of heat. The hormone oestrogen is produced under the influence of other hormone called the Follicle stimulating hormone.
After every 21 days the ovary releases a mature ovum and the cow comes on heat. The ovum travels through the fallopian tubes to the uterus.
The release and movement of the ovum down to the uterus is called ovulation. If mating is done at this time, fertilization will take place.
The fertilized egg implants itself onto the endometrium(walls of uterus)and develops into foetus.
Fallopian tubes:
Fertilization takes place here. Also a passage for the egg from the ovary to the uterus.
The uterus:
Implantation takes place here and also embryo develops here.
The cervix of the uterus: Closes the uterus.
The outer opening
The outer opening is the external opening of female reproductive system.
It allows mating to take place so that sperms are deposited
The foetus and urine are removed through the The outer opening.
Pregnancy period for most farm animals
is period between fertilization of ova and the expulsion of the foetus through the The outer opening. Also called gestation period. In cattle gestation period is 270-285 days. Ends with the birth of a calf.
The reproductive tract undergoes a period of rest during which it is repaired and returns to normal. During pregnancy, hormone called progesterone is produced by the placenta to maintain the foetus in the uterus.
Animal Length of days
Cow 270-285 Days
Sow 113-117
Ewe/Goat 150
Rabbit 28-32
Act of giving birth called parturition. This time the foetus expelled through the birth canal.
When an animal is about to give birth, it shows signs;-
Distended udder which produces thick milky fluid called colostrums.
Swollen outer opening producing thick mucus like discharge.
Loose and slackened pelvic girdle.
Visible pin bones.
General restlessness.
Animal parturates within 2-3 hours after this signs. The correct presentation is with the front feet first ,and the head outstretched and resting in between the feet.
Any other presentation called mal-presentation or breech presentation and requires assistance.
Reproduction in Poultry
The male chicken has no special male organ but a small opening near the vent through which sperms are emitted. male chicken has testes within the body.
The hen has elongated oviduct for formation of an egg. Fertilization occurs internally.
During mating the cloaca of the hen and the vent of the male chicken fit into each other and then seminal fluid is poured into the cloaca ,then sucked to the oviducts.
The Reproductive System of a Hen
The reproductive system has the following parts;
i). Ovary
ii). Funnel(infundibulum).
iii). Magnum
iv). Ishtumus
V). Uterus/Shell gland
vii)
viii). Cloaca
read more of poultry management here
Ovary
Hen has two ovaries but one functional. Ova is formed in ovaries.
About 3500-4000 ova present inside ovary held by follicle. Mature ovum released via rapture of follicle. It moves into oviduct received by the funnel.
Funnel (infundibulum)
Fertilization occurs here. Chalazae also added to yolk.
It also collects the ovum and stores the sperm. Time here is 15 minutes and it is 11.6cm long.
Magnum
Thick albumen is added and stays for 3hrs. its 33cm long.
Isthmus
Its 10.6cm long, Shell membranes added and determines shape of egg.
Water, mineral salts and vitamins added and takes 15 minutes.
Uterus(shell gland)
Calcium deposits i.e.shell added around the egg. Pigments added.
Addition of albumin finished and stays here for 18-22hours.
Cloaca
Egg moves out of cloaca through the vent and the cloaca extents out to prevent the egg from breaking.
NB;
Egg formation not depended on fertilization. Egg formation takes 24-26hours.
The components of egg are obtained from body reserves of the hens body.
Selection of Breeding Stock
Selection is used as a tool for livestock improvement. A breeding type is a group of males and females which act as parents of future generations.
Selection is the process of allowing certain animals to be parents of future generations while culling others.
Culling is the removal of animals which do not perform to the desired level, from the herd. The animals retained have certain desirable characteristics which make them produce more.
Selected animals make up the breeding stock.
The breeding stock should pass the good qualities to their offspring for better performance, to improve the livestock.
Selection process repeated for many generations increases chances of formation of desirable qualities in an animal.
Genetically termed as gene frequency(occurrence of the genes that carry desirable characteristics.) Selection increases occurrence of desirable genes and decreases occurance of undesirable genes.
During selection, the characteristics to be selected for are first studied closely to ascertain that it is not influenced by the environment, but mainly by the genetic make-up.
Selection helps improve characteristics which are highly heritable.
Heritability means the likelihood of a particular trait to be transmitted to the offspring and they are strongly inherited.
A character like milk yield is lowly heritable, i.e. it is weakly inherited and a bigger percentage of the character is affected by the environment.
The degree to which selection affects a character depends on the following factors;
The heritability of the character, The intensity with which the selection is done and the interval between generations and kind of selection being practiced.
Factors To Consider When Selecting A Breeding variety.
Age
Level of performance
Physical Fitness
Health
Body Conformation
Temperament or Behaviour
Quality of products
Mothering Ability
Adaptability
Prolificacy
Age
Young animals,
Those that have not parturated for more than 3-times, should be selected.
They have a longer productive life.
Old animals are poor breeders and low producers.
Production and breeding efficiency decline with age.
Level of performance
Animals with highest production level selected.
Performance best indicated by records.
Good performance of animal indicated by;
High milk, wool and egg production,
Good mothering ability
High prepotency which is the ability of a parent to pass good qualities to their offspring.
The animals with poor performance should be culled.
Good records kept and used by the farmer for this purpose.
Physical Fitness
Animals selected should be free from any physical defect e.g.
mono-eyed,
limping,
irregular number of teats,
scrotal hernia,
defective and weak backline
Health
Sick animals do not breed well and are expensive to keep.
Animals that are resistant to diseases pass these characteristics to their offspring
Body Conformation
Animals for breeding to be selected according to proper body conformation.
A dairy cow should be wedge-shaped with a large udder, thin legs, long neck.
Temperament or Behaviour
Animals with bad behaviors should be culled. e.g Cannibalism, egg eating, aggressiveness, kicking
Quality of products
Select animals that give products of high quality such as meat, wool, eggs, milk.
Mothering Ability
Animals selected should have a good mothering ability,
That is animals with good natural instinct towards their young ones.
This will enable them to rear the young ones up to weaning.
Adaptability
Animals selected should be well adapted to the prevailing climatic condition in the area e.g Arid and semi arid areas.
Prolificacy
Animals selected should be highly prolific.
That is, animals with the ability to give birth to many offspring at a time(larger litter).
This is a quality that should be considered when selecting pigs and rabbits.
The ancestry records assist to choose the prolific breeds for mating
SELECTION OF CATTLE AND SHEEP
Selection in cattle
Consider the following;
Level Of Performance Which Include;
Milk Yield Butter Content.
Length Of Lactation Period.
Calving Intervals.
Age of the Animal, Fertility, physical Fitness, Health Of The Animal, Body Conformation and suitability of the enterprise-milk or beef
Consider the following;
Level of performance which includes;
Mothering ability
Growth rate
Wool quality
Carcass quality
Twining rate Age
Suitability to the enterprise-wool or mutton
Flocking instinct Health of the animal
Physical fitness
Inheritable defects
Fertility
Inheritable defects.
Fertility.
Selection in Goats
Consider the following:
Fertility.
Mothering ability.
Growth rate.
Twining rate
Carcass quality/dressing percentage
Growth rate.
Suitability to the enterprise – milk or mutton.
Health of the animal.
Age.
Selection in Pigs
Consider the following:
Carcass quality/dressing percentage
Suitability to the enterprise (bacon or pork)
Growth rate.
Health of the animal.
Mothering ability.
Prolificacy.
Number of teats
Temperament.
Body formation.
Age.
Heredity defects
Selection in Camels
Health of the animal.
Age.
Temperament.
Foraging ability.
Fertility.
Level of performance-milk, meat, fur and transport.
METHODS OF SELECTION IN REPRODUCTION
These include:
Mass selection – Animals with superior characteristics (highly heritable breeds) are selected from a herd and then allowed to mate among each other at random. The offspring will show higher performance than their parents. This is because mass selection increases the occurrence of the desirable genes in a population.
Progeny testing – is a offspring resulting from selected parents ( Family selection). In this method a group of progenies (offrpring) are used as an aid to increase accuracy in the selection of a breeding type. This is method is used when the character to be selected is of low heredity power and expressed by one sex only.
This method takes up to nine years for the results to be seen
Contemporary comparison
Contemporaries refers to other heifers in the herd sired by the same bull.
This is a progey tasting method which involves comparison of average production of daughters (Heifers) of each bull with that of the other heifer reffered to as contemporaries.
In this methods it is assumed that the difference between the herds of the same breed are non-genetic in origin.
advantages
It is possible to compare heifers of different ages in different locations worldwide.
It eliminates difference brought about by the environment.
it is possible to make direct comparison of stut bulls at different artificial insemination centres.
It is accurate since we are using a large herd of animals.
. AGRICULTURAL MECHANIZATION
24. THE CONCEPT OF MECHANIZATION
25. PROBLEMS OF MECHANIZATION
26. SURVEYING AND PLANNING OF FARMSTEAD
27. IMPORTANCE OF FARM SURVEY
28. SURVEY EQUIPMENT
You must log in to post a comment.