artificial insemination

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Artificial Insemination Mrs. Subalini Elango Department of Animal Science Eastern University, Sri

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Page 1: Artificial Insemination

Artificial Insemination

Mrs. Subalini Elango

Department of Animal Science

Eastern University, Sri Lanka

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Artificial Insemination

What is Artificial insemination ?

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Artificial Insemination

Artificial insemination is the technique in which semen with living sperms is collected from the male and introduced into female reproductive tract at proper time with the help of instruments.

The first scientific research in artificial insemination of domestic animals was performed on dogs in 1780 by the Italian scientist, Lazanno Spalbanzani.

It is a powerful tool mostly employed for livestock improvement.

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Artificial insemination of farm animals is very common in today's agriculture industry in the developed world, especially for breeding dairy cattle (75% ) and swine (up to 85%). It provides an economical means for a livestock breeder to improve their herds utilizing males having very desirable traits.

Artificial Insemination

The first person to use artificial insemination (AI) successfully in cattle appears to have been E.I. Ivanoff, a Russian scientist, around 1900.

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Today, the artificial insemination has become a normal method of breeding quality cattle.

A large number of cows and buffaloes are inseminated artificially.

The technique of artificial insemination is particularly more useful in a country like Sri Lanka where the scarcity of quality sires has been the main barrier in cattle improvement.

Artificial Insemination

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Semen Collection

Semen is often frozen using liquid nitrogen and stored in individual straws for later use.

The first step in the AI process is to collect semen from the bull.

Semen is typically collected using an artificial vagina or by electro-stimulation.

After collection, semen is examined for quality. If the quality is acceptable, the semen is extended with a diluent to make it more suitable for freezing and fertilization.

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Various methods of collection of semen have been devised from time to time..

The three most common methods are:

(i)use of an artificial vagina

(ii)electro-stimulation technique

(iii)by massaging the ampulae of the ductus difference through rectal wall.

Suitability of a particular method depends on the type and condition of a species, e.g. artificial vagina method is applicable to almost all of our domestic animals but certainly not on poultry, where the massage method is the only practical solution to get ejaculation.

Methods of Semen Collection

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Artificial vagina• Most widely used today for the collection of bull semen. • Allow your bull to mount a "teaser" cow. When he begins to ejaculate, redirect his penis into an artificial vagina. •The artificial vagina consists of a firm cylindrical tube with a thin-walled rubber lining. •The jacket formed is filled with warm water (45-50 degrees celcius). • A rubber funnel is attached to one end of the cylinder. • Cleanliness must be practiced to avoid contamination and deterioration of semen quality. • Need a specialized skill, proper equipment, training and experience. Adequate facilities for controlling the bull and teaser animal must be maintained so that danger of injury to personnel as well as the animals is minimized.

Collection of Semen

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Collection of Semen

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Advantages of Artificial Semen Collection through artificial vagina method

1. Practically the whole ejaculate is collected in uncontaminated and natural stage.2. Sterile conditions of the apparatus ensure disease control.3. The viability of the sperm is better.4. No female is needed if dummy is a success

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Disadvantages

The technique of artificial vagina for semen collection has the following disadvantages.

1. Occasionally it is difficult to get the males to serve the artificial vagina.

2. The apparatus involved is slightly costly and requires technical hands.

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Electro-ejaculation method of semen collection in cattle.

By this method of ejaculation of semen is brought about by inserting a probe or electrode in sires rectum and stimulating nerves of the reproductive system by gradually increasing voltage in rhythmic fashion with a for a short period.

Successful use requires skill, experience, patience and the knowledge of individual requirement of the stimulation.

The method is used on males of certain species where the use of artificial vagina is not possible or not practical.

The widest use of electro-ejaculators has been observed in obtaining semen samples from large number of bulls

The method is also used to collect semen from bulls for artificial insemination when the bull is extremely slow in serving the artificial vagina or physically incapable of mounting; The method of semen collection in bull is as follows

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The probe is then inserted up to about 12 inches and held in a position of rectal floor.

Alternate current increasing in voltage gradually from 0 to 5 volts and returning again to zero within every 5 -10 seconds

At about 5th stimulus a maximum of 10 -15 volts is reached. Erection and ejaculation occur at 10 -15 volts when 0.5 to 1A current is flown.

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Advantages

1. Semen can be collected from males that are too young or old or unable to mount due to weak or injured legs.2. No female or dummy is required for collecting the semen.

Disadvantages1. The method is highly technical and needs considerable skill and practice.2. The semen generally gets contaminated with urine.3. Some males resist too much to this method and refuse collection.4. Sciatic nerves are temporarily affected during the operation

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Massage Method

The artificial vagina method of semen collection has following advantages This method involves the simplest technique of semen collection by massaging the seminal vesicles and ampulae. Undoubtedly the collector have a considerable training to adopt the skill. This method is commonly used to collect semen from cock, turkey anddog.

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. Properties of Semen

• Semen is a white, opaque, creamy fluid, occasionally yellowish green due to the pigment carotene.

• Semen consists of cellular part spermatozoa or sperms and the fluid parts, known as seminal plasma.

•Spermatozoa is a male germ cell apportioned into three regions: head, middle piece and tail.

•The shape of the head of the sperm in the bull, ram, boar and rabbit is a blunt ovoid. In fowl, the sperm head appears as elongated cylinder.

•In the bull, the spermatozoa measuring 80 microns in length resembles an agile tadpole.

•The head is a blunt ovoid structure known as acrosane.

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• The liquid portion of semen • The volume of single ejaculate in the bull ranges from 2-10 mI.

•Variations in quantity may be due to 1.Breed differences 2.Age3.Frequency of service4.Season 5.Nutritional status of the individual

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Examination of Semen for Quality

Once semen is collected, it is examined to judge its suitability for inseminations.

There can be two types of examinations,

(i)a routine examination of every sampIe of semen collected

(ii)a more detailed examination done at much longer intervals to study the suitability of a male for artificial insemination before initiating it to A.I. and at half-yearly or yearly intervals to evaluate if the male is continuing to produce sufficient viable sperms or not.

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Examination of Semen for Quality

In the routine examination

• colour

• volume

• mass activity (initial gross motility)

• individual motility after dilution

• sperm density and percentage mortility

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The main reason for extending (diluting) semen is to increase the number of females serviced from one ejaculation.

A normal ejaculate from a dairy bull will contain 5 to 10 billion sperm which can be used to inseminate 300 to 1000 cows if fully extended.

There are several good semen extenders. Those made from egg yolk or pasteurized, homogenized milk .

Semen extension

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A good extender not only adds volume to the ejaculate but favors sperm survival and longevity. Dilution rate depends on quality of the ejaculate--number of sperm cells, percent alive and mobility.

As few as 12 million sperm per insemination have given good conception rates.

Penicillin and streptomycin are added to semen extenders. These antibiotics inhibit bacterial growth and reduce danger of spreading diseases such as vibriosis.

Semen Extension

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Typically, the extender contains

1. Milk or egg yolk to protect against cold shock2. Glycerol (to protect damage due ice crystals

during freezing3. A buffer (usually citrate) to prevent pH changes

due to lactic acid, produced during sperm metabolism

4. Glucose (and/or other sugars) to provide an energy source for the spermatozoa

5. Antibiotics, to kill pathogens.

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The bull semen can be successfully frozen and stored for indefinite periods.

In 1949, British scientists discovered that addition of glycerol to the semen extender improved resistance of sperm to freezing. Glycerol acts to remove water from the sperm cell prior to freezing and prevents the formation of cellular ice crystals which would damage the sperm.

There are two methods of freezing and storing semen: dry ice and alcohol and liquid nitrogen. Liquid nitrogen is preferred because there is no evidence of fertility deterioration with age. Fertility gradually declines in semen stored in dry ice-alcohol.

Semen storage

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Frozen semen can be stored indefinitely if proper temperature is maintained. A recent report told of a calf born from frozen semen stored for 16 years. Fresh, liquid semen can be successfully stored for 1 to 4 days at 40 degrees F.

Semen is usually stored in glass ampules

Semen storage

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If cows show estrus in the morning should be inseminated in the afternoon of the same day. If observed in the afternoon should be inseminated the next morning.

Estrus detection and insemination time in cow

Usually cows come in estrus after every 21 days if non-pregnant.

In the cows, estrus is indicated when the female stands to be mounted by another animal.

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A successful heat detection program and subsequent proper timing of insemination will increasing reproductive efficiency.

Timing of Insemination for Maximum Conception

Conception rate is lower when cows are bred prior to mid-estrus or later than 6 hours after cessation of estrus (standing heat in this case). Maximal conception is obtained when cows are inseminated between mid-estrus and the end of standing estrus, with good results up to 6 hours after estrus.

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In the cow, the best fertility can be obtained with the recto-vaginal technique.

Semen deposition

Early methods of AI involved deposition of the semen in the vagina, as would occur in natural mating. Those methods are not satisfactory. Fertility is low and greater numbers of sperm are required.

In the recto-vaginal technique a sterile, disposable catheter containing the thawed semen is inserted into the vagina and then guided into the cervix by means of a gloved hand in the rectum.

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The inseminating catheter is passed through the spiral folds of the cow's cervix into the uterus. Part of the semen is deposited just inside the uterus and the remainder in the cervix as the catheter is withdrawn.

Semen deposition

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How to perform?

AI can be carried out by technicians from approved AI centres or by qualified vets

Semen is stored in plastic straws, holding 0.25cm3 of semen. Filling and labeling of straws is mechanized.

For insemination, a straw is fitted into a special insemination gun (catheter) which is inserted into the cow's vagina and positioned so that the semen is deposited beyond the cervix.

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Semen deposition

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The success of insemination depends mainly upon

(i)The inherent fertility of the sperm

(ii)Proper handling of the semen prior to insemination

(iii)Insemination at right time during estrus

(iv)Proper semen deposition

Artificial Insemination

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Advantages of AI over natural breeding

Farmers have access to genes from bulls of a quality which they may not individually afford.

Frozen semen can be transported globally.

(A.I.) increases the usefulness of superior sire to an extra ordinary degree.

The services of superior sires are greatly extended. By natural services, a bull can be bred to 50 to 60 cows per year. On the other hand, by artifical insemination technique thousands of cows can be sired in one year by one bull.

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Advantages of AI over natural breeding

Disease control. Many potentially devastating diseases are spread by sexual contact.

Cost effectiveness. The cost of an AI straw is around £10, this is as nothing compared with the costs of a Holstein bull (possibly £10,000 to buy). A bull is expensive to rear, is relatively unproductive, vulnerable to disease or accident and may even prove to be infertile..

The breeder does not need to maintain a herd sire and thus can avoid the botherations accompanied with the management of a bull.

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Advantages of AI over natural breeding

Flexibility. For a variety of reasons, a herdsman may not wish all calves to be sired by a single bull with the same characteristics. It may well be impracticable to keep sufficient bulls to cover all possible requirements.

A bull can typically breed 50 to 60 cows per breeding season via natural service, with AI that same bull can impregnate a virtually limitless number of cows each year.

The dairyman does not have the problem of searching and purchasing a new herd sire every two years to avoid inbreeding.

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7. It overcomes the difficulty of size and weight.

8. It increases the rate of conception in females.

9. Outstanding animals located apart can be mated.

10. It helps in better record keeping.

11. Old, heavy and injured sires can also be used with

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1. It requires well trained operators and special equipments.2. It requires more time than natural services.3. It necessitates the knowledge of structure and function of reproduction on the part of the operator

4. Improper cleaning of the instruments and insanitary conditions may lead to lower fertility.5.Market for the bulls is reduced while that for the superior germplasm is increased.6. Selection of the sire should be very rigid in all respect.

Disadvantages

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7. Preservation and transportation of semen is difficult under severe climatic conditions like those prevailing in most parts of India.

Disadvantages

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7. Preservation and transportation of semen is difficult under severe climatic conditions like those prevailing in most parts of India.

Disadvantages

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Tips & Warnings

•Keep your inseminating supplies dry and clean at all times. •If your cow moves during the insemination process or if the rod slips out of place, stop semen delivery and reposition the rod.•Do not attempt artificial insemination on your own if you are untrained in the procedures or if you lack knowledge of bovine anatomy. • The collection of semen and the insemination of your cow should be done by or under the supervision of a qualified technician