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Yana Mani NepalB.V.Sc & A.HRoll No. 31

Artificial insemination techniques in dairy cattle

Clinical conference II

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Artificial insemination

very simply means taking sperm from the

best male animal and putting into the best

female animal.

used extensively in modern farming to

produce best diary and beef cattle and in

the breeding of race horses.

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It was in 1780 that the first scientific

research in AI of domestic animals, was

carried out on dogs.

Lazanno Spalbanzani, an Italian scientist,

conducted experiments that proved the

power of fertilization vested with the

spermatozoa and not with the liquid

portion of the semen.

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AI is a remarkable method of breeding quality cattle in the most natural way possible.

AI is being carried out in a large number of buffaloes and cows and is extremely useful in countries like Nepal, wherein quality sires have been scarce.

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Interesting fact….Semen volume/ejaculate: 6 ml

Sperm concentration: 1.2 billion/ml (motility: 70%)

Total sperm/ejaculate: 6x1.2billion ¡Ö 7.2 billion Sperm motility of diluted, frozen and thawed semen: 40 Total post-thaw motile sperm/ejaculate: 0.40x7.2 billion= 2.88 billion

Post-thaw motile sperm required/insemination: 10 million Breeding units/bull/day: 2.88 billion/10 million = 288 units Intervals of semen collection: 3 days (95x) and 2 days (40x) Semen collections/year: 95 + 40 = 135 times

Breeding units/bull/year: 135 times x 288 units = 38,880 ¡Ö 40,000

Reproductive life after progeny test: From 4 to 10 years old = 7 yrs. Breeding units available from a tested bull: 40,000x7 ¡Ö 300,000

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Advantages of AI• Use of proven stock quality

• Frozen semen can be transported globally and stored for many years

• Cost effective - A bull is expensive to rear, relatively unproductive, vulnerable to disease or accident and may be infertile.

• Flexibility: high yield dairy cows can be crossed with dairy bull semen to create more higher yield cows.

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Advantages contd…

• Safety: bulls are aggressive

• Disease control: Vibriosis, trichomonasis, campylobacteriosis and brucellosis

• Use bulls with certain characteristics which complement those of the particular cow (as milk yield, milk fat%, or udder conformation etc)

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Disadvantages

Main disadvantage is that the same alleles keep appearing in the population so there is a loss of diversity in the gene pool (many genes are lost). So a disease could wipe out an entire population if resistant alleles have been lost.

Much time is required in checking females for estrus

Some special facilities for corralling and inseminating

Trained personnel  

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ARTIFICIAL INSEMINATION TECHNIQUES

1. Semen collection

2. Semen evaluation3. Semen Processing, Storage,

Thawing, and Handling

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Semen collection

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Method of semen collection

1. Taking semen from vagina with spoon or

rubber breeding bag

2. Massaging vesicular gland and ampullae

by way of rectum

3. Artificial vagina

4. Electroejaculation

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Collection through artificial vagina

AV should be held parallel to the expected path of bull's penis, after false mounts

Guide penis to the side by grasping sheath

and direct it into AV

Bull will thrust and ejaculate simultaneously

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FALSE MOUNTING: Deviating penis to side during mount. Sexually stimulates the bull.Providing two false mounts with two minutes of active restraint and one additional false mount maximizes sperm cell numbers.

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Principle: Electrically stimulating nerves to male reproductive system Uses for bulls

a. For crippled, aged or sexually low active dairy bulls b. For checking semen quality of beef bulls prior to natural breeding season

Equipment: A bipolar electrode and a variable source of alternating current: voltage: 0 - 30 V, amperage: 0.5 - 1.0 A; alternating + and - rings spaced 4cm apart, running longitudinally along the electrode

Electroejaculation

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Electroejaculation procedure in bull

Restrain the bull in a chute with good footing provided

Remove excess faecal material from rectum

Insert lubricated electrode into rectum

Stimulate electrically for 2 to 5 min: low voltage at gradual increase (a few volts at a time) up to 15 V or higher, with 4-second rest period between stimulations

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Semen EvaluationEvaluate semen quality by

volume,

colour,

consistency,mass motility (overall movement observed in the microscopy, "waves"),

individual motility of sperm cells

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Normal Parameters

http://www.vivo.colostate.edu/hbooks/pathphys/reprod/semeneval/bull.html

Parameter Normal Values

Ejaculate volume 5 ml (range 1-15 ml)

Sperm concentration 1200 million/ml(300-2500 million/ml)

Total sperm per ejaculate Typically 4-5 billion

Progressive motility Greater than 30%

Morphology Greater than 70% normal

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ColourOpacity: Indication of concentrationColour: acceptable colour ranges from milky to creamy (Note: This indicatessperm per cubicmillimetre of 500,000 orabove.Other colours indicatingless than 500,000 sperm/cu mm would be opalescent (cloudy) to watery.

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Bulls: > 30% progressively motile spermAdversely affected byheatcoldresidue on collection equipmentwrong pH or osmolalitysexual inactivity

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Semen Processing, Storage, Thawing, and Handling

Processing steps of frozen bull semen

Dilution

Cooling

glycerolation & equilibration

packaging

freezing

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Semen dilution

PredilutionWarm semen with 3 to 4 volumes of diluter

tempered in the same water bath Lecithin and lipoprotein from yolk of diluter:

Protect sperm from cold shock and prevent changes in cell wall permeability during cooling process

Dilution After cooled to 50C

, the pre-diluted semen is diluted to final volume with diluter cooled to 50C

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Cooling semen Optimum cooling rate: From body temperature to 5oC for

1.25 to 2 hours (fast cooling) or for 2 to 4 hours (slow cooling)

Glycerolation Sperm protection from freezing by glycerolation: Because

glycerol binds water, glycerolation results in

a. Decreased freezing point of solutions

b. Less ice formed

c. Correspondingly decreased concentration of solutes

d. Partially dehydrated sperm cells

e. Reduced selective freezing of water

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Semen packagingPlastic straws a. Size: 0.5 ml with 113 mm long and 2.8

mm in diameter (In Europe 0.25 or 0.3 ml straws are used)

Freezing Freezing procedure: A single layer of

straws are placed on a tray at 5.5 cm above the liquid nitrogen level; Straws will reach the temperature of liquid nitrogen vapour in about 2 min.

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Storage of bull semen Optimum temperature for semen storage

a. Liquid semen: at 50C b. Frozen semen: below -750C

Semen storage in liquid nitrogen containera. Double wall stainless steel or aluminium container with a vacuum between the wall

b. Field unitLiquid nitrogen capacity: 20 litres Holding time: 90 days Storage capacity: 1,200 straws of 0.5 ml capacity Recharging interval: 60 days

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References

http://nongae.gsnu.ac.kr/~cspark/teaching/lecture_under.html

http://www.fao.org/AG/aga/agap/frg/FEEDback/War/u6600b/u6600b0m.htm#TopOfPage

www.das.psu.edu/reproduction/insemwww.msue.msu.edu/msue/imp/modaa/163

60001.htmlhttp://www.buzzle.com/www.vet.ksu.edu/studentorgs/bovine/pdf/

artificial_insemination.pdf

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Thank You