Preparation for ai lecture 4

4/24/2017ANS203 BSc Animal Science 1
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རང་འབྱུང་འཐློན་བསྡེད་མཐློ་རིམ་སློབ་གྲྭ།
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ལློད་སྦུད་ས།
27/03/2017

Preparation of Artificial
Insemination.

Preparation for Artificial Insemination
Learning outcomes.
By the end of the lesson, each student should be
able to;
1.Remember the points to be considered before
AI
2.Recall the Instrument required for AI
3.Explain the technique of thawing of Semen.
4.Demonstrate AI procedures
5.List down the general precautions during AI

Before you inseminate the cow, you should
have clear cut idea about the approximate
time for AI.
To know the approximate timing for AI,
you must have following basic ideas.
1.Estrus cycle, estrus period.
2.Causes of Heat signs
3.Average life span of spermatozoa and Ovum.

The Estrous Cycle
Time period between 2 estrus cycle.
Species differences in various characteristics of the
estrus cycle:
17 days for the Ewe, 21 days for the Cow and Doe, 22
days for the Mare and 20 days for the Sow.
Estrous cycles ranging from 17 to 24 days are
considered normal for heifers as well as for cows, and
A range of 19 to 25 days is reported in the Mares.
Ovulation Timing
Cow: 10-12 hours after estrus
Mare: 1-2 days before estrus ends

Phases of Estrus Cycle (Bovine)

Average life span of spermatozoa and Ovum.
Estrus Period.
12-18 hrs. (cow) 24-36hrs(ewe) 48-72 hrs.(sow)
4-8days (Mare)30-40 hrs.(Doe)
 sperm viability usually is estimated to be 18 to 24
hours.
 The fertile life of the egg is shorter than that of
the sperm. Ovulated eggs remain fertilizable longer
(10–20 hours)

Day 0: Defined as the day of estrus. During this
period, a cow will stand to be mounted.
Heat usually lasts for an average of 8 – 12 hours but
can sometimes last as few as four hours.
 During this time the follicle structure on the ovary is
present. Estradiol from the follicle triggers GnRH
release.
When GnRH is released, it will also cause the release
of LH, which in turn induces ovulation and releases the
egg.
The LH surge occurs at the onset of estrus (Day 0);
ovulation occurs approximately 32 hours following the
LH pulse.

If sperm are present when the egg is released,
fertilization will occur—a fertilized embryo will stay in
the oviduct three to four days before moving to the
uterus.
Day 1 – 5: The follicle “luteinizes” to form the CL which
secretes progesterone.
Day 9 – 10: The CL reaches maximum size and
progesterone output.
Day 16 – 18: If a cow does not become pregnant PGF2α
will be released by the uterus.
As progesterone levels decrease and an increase in
GnRH pulsatility takes place, release of LH increases,
and a preovulatory estrogenic follicle develops.
Continued…..

Points to be considered before inseminating
the animals
minimum of 250 kg in cattle heifers and 300 kg in
buffalo heifers.
Animal should be in estrum.
The reproductive tract should be free of infection
Discharge should be clear.
Congenital or hereditary anatomical defects of
reproductive tract should not be there.
Animal should not be pregnant. Before performing AI
rule out pregnancy.
there should be gap of 60 days from the time of
parturition.

 If abnormal calving in previous parturition, the time
gap of 90 days is preferable.
 The type of semen – breed, bull no should be
decided well in advance.
 Insemination while standing posture is
recommended.
 Stress should be avoided.
 AI area should be clean and free from noises.
Continued……..

 Cutting must be straight to avoid semen back flow.
 AI gun must be locked after loading the straw.
 Avoid shock to semen during handling.
Preparation of Animal for AI
1.Clean the Genital area of the animal with warm
water.
2.Remove any dirt from the body of the animal
3.Put the animal into the service crate to restrict the
motion during AI
4.Always perform AI in a quiet place.
5.Atleast one attendant should accompany the
inseminator.

Materials Required for AI
N2 cylinder
H2O bath 37 Degrees
Tissue PaperThermometer
cotton
AI sheaths
scissors

Preparation For AI
Proper insemination techniques involves;
Proper identification of the cow before insemination.
 Interrogating the farmer in order to obtain a clear picture about the
history of the cow.
 External examination of the cow to be inseminated.
 Proper selection of the semen.
 Application of the correct thawing techniques where frozen semen
is used.
 Proper preparation of the insemination gun.
 Hygienic handling of insemination gun and animal.
 Thorough rectal examination of vagina, cervix and uterus before
actual insemination.
 Proper introduction of the gun into the cervix.

Deposition of semen in the right spot in the genital tract of the
cow.
Careful approach and handling of the cow during
insemination.
Proper recording of A.l. in the A.l. register.
Proper cleaning and handling of all materials and equipment.
Thawing and loading of AI gun

Thawing: It is re-warming of frozen semen to 37ºC in pre-
warm water
Material required: Small liquid nitrogen container, a flask
for hot water, a thawing flask, thermometer, gloves,
insemination guns, plastic sheaths, scissors, paper towel or
cotton and soap
Procedure
 Take out the frozen semen straw with a long neck forceps
out of the frozen semen container
 Thaw straw horizontally in water at 35-37oC for 30 seconds.
 Wipe the semen straw with tissue paper or absorbent cotton
properly.

 Hold the gun in your left hand, pull the piston almost 13-
14 cm outside.
 Load the straw in the AI gun in such a way that powder
plug end remains outside the gun.
 Cut the powder plug giving a straight and vertical cut to
the straw while keeping the gun parallel to the ground.
 Cover the AI gun with insemination sheath and lock it
with plastic ring provided with the gun.
Precautions
 Canister should not be above frost line of liquid nitrogen.
 Temperature of water should be proper.
 Straw after thawing must be dry to avoid contamination
with water.

Estimating the best time for AI
Heat Signs.
The primary heat signs is when a cow stands to allow a herd mate to
mount (most reliable heat signs but difficult to observe)

Secondary heat signs include,
 attempting to mount other animals,
 chin resting , increased activity,
 clear mucus discharge from vagina and tumification.
 As a veterinarian, animals in heat can be detected by
Rectal palpation. Animals in heat will have soft and
pliable cervix and rigid and contracted uterine horns
(tonicity).
 if the cervix is hard and rigid and the uterine horns are soft
and flabby it is unlikely that the animal is in heat.

Timing of Insemination.
 Insemination should always be preferred at least 10-12
hours before ovulation.
 Optimum time to inseminate a cow is between 6 to 18
hours after onset of estrus (standing estrus).
On average, AI should be done 12 hours before ovulation
 Trim Berger and Davis in 1948 devised a A.M and P.M
rule for AI i.e Animals observed in heat during the A.M
should receive A.I during the PM and animals observed
in heat during PM should receive A.I during A.M

Average life span of Sperm and Ovum
Sperm viability usually is estimated to be 18 to 24 hours.
The fertile life of the egg is shorter than that of the sperm.
Ovulated eggs remain fertilizable longer (10–20 hours)
 Too early inseminations will result in the spermatozoa
being dead before ovulation has taken place.
 Inseminations at too short a time before ovulation result in
lowered conception rates as the ovum can be dead before
the spermatozoa is capable of fertilization.

Insemination Methods
There are two methods;
1. Speculum method.
Low conception rate and regular cleaning needed. Not used
anymore.
2. Recto-vaginal method.
The most commonly used technique through out the world but
requires great expertise and proficiency.

SEMEN
1.Chilled Semen
2.Frozen Semen
A. AI With Chilled Semen: Recto-vaginal Method
Materials required: Thermos with ice, sterilized wrapped glass pipette
(40-42 cm long, outer diameter 5-6 mm, inner diameter about 1 mm),
air tight chilled semen vial, towel, soap, gloves, rubber adopter, syringe
and record book.
Procedure.
 Restrain animal properly and clean the perineum.
 Sterilized glass pipette is fitted to a clean and dry syringe (capacity
2-5 ml) with rubber connector / adopter.

The vial containing semen is gently shaken to mix the semen just
before filling the semen in to the AI pipette.
Suck 2 ml air in the syringe and then suck semen in the AI glass
pipette (1-1.5 ml)
Insert lubricated hand in the rectum and after removing dung, grasp
cervix and place thumb at os-cervix.
Pull apart the vulvar lips and pass loaded glass pipette through
vagina at 45º angle.
Push cervix forward to straighten the vagina and abolish vaginal
folds.
Manipulate glass pipette gently so as to strike the thumb placed
already at cervix and direct through the cervix.

 Pass the glass pipette to the mid cervix of the animal by recto-
vaginal method under hygienic conditions.
 Deposit the semen and take out the pipette.
 Massage the clitoris at ventral commissure of vulva.
 Glass pipette is properly washed, dried, wrapped and sterilized for
further use.
AI with frozen semen: Recto-vaginal method
Materials required: Small liquid nitrogen container, thawing
flask, thermometer, gloves, insemination guns, plastic
sheaths, scissors, paper towel or cotton, soap and record
books

Procedure
 Restrain the animal and pass the AI pipette same way as
with the chilled semen.
 Deposit semen at body of the uterus.
 Withdraw AI gun together with the arm in the rectum.
 Massage the clitoris at the ventral commissure of vulva.
Depositing the semen in the body of the uterus

Organization of AI and Record Keeping
Recording system for Andrology and artificial
insemination
 The recording of reproductive parameters / events in
a systemic way facilitates better selection of
personnel/animals for planning and implementation of
breeding program

Preparation for ai lecture 4

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