Transcript Document

ARTIFICIAL
INSEMINATION
Agriscience 332
Animal Science
8818-A
TEKS: (c)(4)(D)
Introduction
Artificial insemination (A. I.) is the
process by which sperm are
collected from a male of a species,
processed, stored, and then
artificially introduced into the
reproductive tract of a female of
that same species for the purpose
of conception.
Artificial insemination is an
important technique for improving
the genetic quality of domesticated
animals.
It has been widely used in dairy
cattle, beef cattle, sheep, swine,
horses, birds, and dogs throughout
the world.
History of Artificial
Insemination
An old Arabian tale reports that an
Arab chieftain wanted to mate his
prize mare to an outstanding
stallion owned by an enemy.
For the chieftain to be able to do this,
he had to steal semen from the
enemy’s stallion.
He introduced a wand of cotton into
the mare’s reproductive tract and then
used it to sexually excite the stallion.
The stallion ejaculated, the semen
was caught in a container, and the
chieftain introduced the semen into
the mare, resulting in conception.
Antony van Leeuwenhook, Dutch
inventor of the microscope, was
the first person to observe sperm
under magnification.
Photo courtesy of Wikipedia.
In 1780, Lazzaro Spallanzani, an
Italian physiologist, was the first to
record the successful
use of AI in his work
with dogs and is
considered the
inventor of AI.
Photo courtesy of Wikipedia.
Ivanoff of Russia pioneered AI
research in birds, horses, cattle,
and sheep in 1899.
He was the first to successfully
inseminate cattle artificially.
By the late 1800’s, American
veterinarians employed AI to get
mares “in foal” that had persistently
failed to settle to natural service.
AI was first used on a large scale
by Russia to reestablish its livestock
industry following World War I and
Britain used it for the same purpose
following World War II.
Today in the United States, AI is
used extensively in many livestock
species.
It has been most widely used for
breeding dairy cattle and research
indicates that more than 65% of
all dairy cattle are bred artificially.
AI has made bulls of high genetic
merit available to all.
Benefits of Artificial
Insemination
• Increased Uniformity – AI makes
development of large numbers
of animals within a superior
family possible, thus providing
uniformity and a better basis
for a constructive breeding
program.
• Economical Service – with
reasonably priced semen, the
value of the progeny produced
exceeds the costs of semen
and service.
• Better Health Protection – AI stops
venereal contact, reproductive
problems in individual females
are more easily detected, and
the infertile males can be
detected at an earlier age.
• Improved Herd Records – sires
and breeding dates of each
offspring are known and more
accurate herd records and
observations result in improved
culling and management.
• Maximizes Use of Superior Males –
one male can be mated to
thousands of females.
• Safety – not having a male
animal on the premises
eliminates the potential danger
of aggressive males, such as
bulls, that could cause harm to
a producer.
Limitations of Artificial
Insemination
• Human Detection of Heat – a very
detailed management practice
(extra human labor) is required
because success or failure
depends on how well heat is
detected in the female
population.
• Requires a Skilled Technician –
proper training and experience
are essential to be successful
with AI.
• May Be Subject to Abuses –
because it is impossible to
differentiate between the
semen of individuals of the
same species, the integrity of
technicians and sire collection
agencies is very important.
• May Accentuate the Damage from
a Poor Sire – because a greater
number of offspring is available
through AI, an inferior sire can
increase his negative influences.
• Requires Additional Capital and
Management – due to extra
labor and facilities which are
usually required because of
extra handling for palpation and
insemination of each individual.
Anatomy and Function of
the Male Reproductive Tract
Before producers can make the
best use of AI, it is necessary to
understand the function of the
male reproductive tract.
A brief review follows. For a more in-depth review, see
lesson #8405.
The testicles produce the sperm
cells and testosterone.
Normally, the testicles are found
suspended in the scrotum, where a
relatively constant temperature is
maintained by raising or lowering
the testes.
Sperm pass from the testes to the
epididymis, where they are stored
and mature.
At the time of mating, or
ejaculation, sperm are carried
from the epididymis through the
vas deferens to the ampullae,
which join the urethra.
From the ampullae, sperm pass
into the urethra, the common
passageway for both semen and
urine.
The seminal vesicles, the prostate,
and the Cowper’s glands are
accessory glands that secrete fluids
that are added to the sperm at the
time of ejaculation.
These fluids help transport the
sperm, supply the proper
environment to keep the sperm
alive, and cleanse the urethra prior
to the time that the sperm pass.
The urethra continues from high in the
body down through the penis.
Semen follows this path at the time of
ejaculation.
The penises of the bull, ram, and boar
are constructed with an S-shaped curve
(sigmoid flexure) that straightens out
at the time of erection and mating to
enable the penis to deposit semen in
the vagina of the female.
Semen Collecting,
Processing, and Storage
Semen is an opaque, whitish fluid,
consisting of a fluid part (from
accessory glands) and a cellular
part (sperm), that is discharged by
the male at the time of mating.
Considerable differences in
individuals and species exist for
semen volume and sperm
numbers, which are influenced by
age, season of year, general
health, and sexual activity of the
male.
The ram is capable of repeated
service without noticeable decline in
volume and sperm concentration.
In boars and stallions, service rates
higher than twice daily usually
affect semen quality.
The sperm cells are microscopic in
size and consist of a head, neck,
body, and tail portion.
In profile, the head of the sperm
is flattened, but as seen under a
microscope, is rounded or oval.
It mainly consists of nuclear
material and is covered by a thin
layer of cytoplasm.
The head is of great importance
because it contains the
chromosomes (DNA).
The neck is short and contains the
anterior centromere.
The body is approximately the same
length as the head.
The lashing of the
tail causes the
sperm to move.
Photo by Keith Weller courtesy of USDA Agricultural Research Service.
Although minor differences occur
in their sizes, all spermatozoa are
extremely small (much smaller
than the egg cells, or ova).
Collection of Semen
The method of collecting semen
should be adapted to the male
of the species and easy for the
operator to use.
It should permit the collection of
a sample of normally ejaculated
semen, free from contamination.
Artificial Vagina
Many techniques are available for
the collection of semen, but the
most satisfactory one consists of
using the artificial vagina.
Males usually respond to this
method with little previous training.
The artificial vagina is the most
satisfactory method of collecting
semen from the bull, stallion, or
boar and may be used for the ram.
An artificial vagina is made of two
tubes, an outer layer of heavy rubber
and an inner lining of thin rubber.
The space between the two tubes is
filled with warm water (45°C or 113°F).
One end of the vagina is left open
to permit the penis to enter.
The other end leads to a graduated
test tube into which the semen
flows after ejaculation.
Best results are usually attained
when the male is allowed to mount
another animal and the penis is
quickly diverted into the open end
of the artificial vagina.
If the artificial vagina was properly
prepared, ejaculation is very
shortly initiated.
Preparation of a bull for collection
is important.
A “teasing” period before collection
results in an improvement in the
quantity and quality of semen
produced.
At collection, as the bull mounts a
cow, a steer, or a dummy, his
sheath is grasped and the penis is
quickly guided into the artificial
vagina.
If the proper technique,
temperature, pressure, and
lubrication have been observed, the
bull will ejaculate immediately.
The average semen volume per
ejaculate, as indicated on the
graduated test tube, is 8 to 10 cc
and contains 8 to 15 billion sperm.
The graduated test tube in which
the semen was collected from the
artificial vagina is taken to the
processing laboratory as soon as
collection is completed.
Electrical Stimulation
The electro-ejaculator was
developed to produce an electrical
impulse to stimulate the nervous
system of the reproductive tract,
causing erection and ejaculation.
Collecting semen by electrical
stimulation has been used on
rams for years, but has only
been used on bulls since 1950.
The use of the electro-ejaculator
has overcome many of the
difficulties experienced in using
other methods for testing range
bulls.
If a bull is restrained properly in a
good chute, semen can be
collected with the machine,
regardless of the bull’s disposition.
Electrodes are inserted into the
rectum of the bull after the feces
are flushed out with a salt solution.
Low-power stimulations given
intermittently are increased
gradually to obtain extension and
erection prior to ejaculation.
The first fluid that passes is a
clear, watery secretion from the
accessory glands that contains
few, if any, sperm cells.
Following this, the ejaculate turns
into a milky fluid consisting of
sperm and accessory fluids.
A collection is made at this time
for evaluation.
The collection is made in a test tube
attached to a flexible plastic funnel
that reduces breakage and injury.
The reproductive organs are
examined for abnormalities at the
time of testing.
Massage of the Ampullae
Massaging the ampullae is a
method of collecting semen that
requires a well-trained operator
who inserts the hand into the
rectum and massages the ampullae
and accessory glands, causing
semen to drip from the sheath.
Semen collected by this method is
of poor quality, because it may be
contaminated with urine and may
contain too much accessory gland
secretion for the number of sperm
present.
However, this massaging the
ampullae method has been used
successfully with bulls and stallions.
Recovery of Semen from the Vagina
This method of semen collection
first allows natural service to occur.
Then, the semen in the anterior
vagina is aspirated into a syringe by
means of a glass or rubber catheter
introduced into the vagina.
Semen collected this way is usually
contaminated with the secretions of
the female and greater danger of
spreading disease exists.
Some operators prefer this method
with sheep, but it cannot be used
with swine.
Semen Processing
Semen that has been collected,
must then be processed.
The processing of semen includes
testing and extending the semen.
Testing of Semen
The thickness, or density, of the
semen is tested in a photelometer,
which estimates the number of
sperm.
Next, the semen is examined under
the microscope to evaluate motility
and morphology of sperm.
A drop of fresh semen is placed on
a glass slide and examined under
the microscope.
The observer notes the percentage
of mobile sperm in the sample.
Rapid forward movement is
desirable; 80% motility is excellent,
70% is good, and 50%-60% is fair.
The morphology, or appearance, of
the sperm should be normal and is
an indication of semen quality.
Abnormal appearances, such as
coiled tails, tailless, irregular shaped
heads, and double heads or tails,
may result from cold or heat shock,
poor nutrition, and endocrine
imbalances.
Extending Semen
The male ejaculates millions of
sperm at the time of mating.
In natural mating, all of these
sperm are used to breed one
female, even though only one
sperm of the millions fertilizes
the egg.
Collected semen can be extended, or
diluted, so that one ejaculation may
be used to breed many females.
This is accomplished by
adding materials to the
semen to keep the sperm
alive for a longer time
period and to give the
sample more volume.
Photo by Keith Weller courtesy of USDA
Agricultural Research Service.
Antibacterial agents, such as
sulfanilamide, penicillin, and
streptomycin, are added to the
extenders to help control bacterial
growth.
To keep sperm alive, it is important
that the diluents be added a few
minutes after the semen is
collected from the male.
It is important to not suddenly cool
the sperm, so the semen and diluent
should always be near the same
temperature.
Sperm can withstand slow cooling,
but cold shock is extremely harmful.
Semen that is undiluted will not
live much longer than 24 hours at
room temperature.
By adding diluents and slowly
cooling the semen to refrigerator
temperature, 41°F, the sperm may
frequently be kept fertile for nearly
a week and active movement can
be maintained for 20 to 30 days.
The reduced temperature slows
the sperm until it is inactive; thus,
its energy is saved.
Storing Semen
Preparations for Storage
After special treatment of semen
with the selected extender, the
sperm can withstand freezing to
extremely low temperatures.
Usually the semen is collected and
diluted in the manner previously
discussed.
After it is cooled, a 7% to 10%
glycerol solution is added slowly
over a one-half hour period.
The sperm are then refrigerated for
6 to 18 hours.
Ampuling
The basic unit for semen storage
and shipment is an individual plastic
straw, containing just enough
semen for a single insemination.
After the semen has been collected,
evaluated, and extended, straws
are prepared to receive the semen.
Each individual straw is identified
with the sire’s name and registration
number, breed, code number, and
identification as to the specific
collection.
The filling and sealing operations
are performed in refrigerated rooms
maintained at 40°F.
Careful attention is given to the
volume of semen in each straw and
to the quality of seal.
Volume of Semen & Concentration Per Insemination
Species
Semen Dilution Ratio
Volume of Semen
Needed per Service
Number of Sperm
per Insemination
Bull
1:200
5 cc15
million
Stallion
-----
5-10 cc
250 million
Boar
1:8
50-100 cc
2 million
Ram
1:1
0.5 cc
50 million
After filling, sealing, and freezing, the
straws are placed into plastic cups
(goblets).
Each goblet holds five straws.
Two goblets are clipped to a metal
holding device called a cane.
This provision for vertical storage
makes it possible to store many
straws of semen in a compact space.
Freezing and Storage
The diluted semen with the glycerol
added is slowly frozen by using
liquid nitrogen or dry ice in an
alcohol bath.
Semen will stay fertile and can be
stored for months or perhaps years
when maintained at -110°F (dry
ice) or -320°F (liquid nitrogen)
until needed for breeding.
It is important that the low storage
temperature be maintained
constantly; otherwise, the sperm
will die.
The technician has
the responsibility
of handling the
frozen semen to
preserve its
quality.
Photo by Peggy Greb courtesy of USDA Agricultural Research Service.
Most technicians store the straws of
frozen semen in a liquid nitrogen
container.
The nitrogen container illustrated
(right) holds up to
540 straws and
may be safely
stored for as long
as 60 days.
Anatomy and Function of the
Female Reproductive Tract
To use AI effectively, it is
necessary to know the anatomy of
the female reproductive system
and how the system functions.
A brief review follows. For a more in-depth review, see
lesson #8405.
The main purposes of the female
reproductive tract are to produce
the egg (ovum) to be fertilized by
the sperm to form the embryo,
serve as a receptacle for the male
penis during copulation, and house
and nourish the fetus until
parturition.
Two ovaries produce eggs from
follicles and produce the female
hormones estrogen and
progesterone, which regulate the
heat cycle and maintain pregnancy.
Infundibulums located just below
the ovaries pick up the eggs at
ovulation and direct them into the
fallopian tubes where fertilization
occurs.
From the fallopian tube, the egg
passes into the uterine horn, where
the embryo attaches to the uterine
wall to be nourished and developed
until parturition.
The horns join to form the body of
the uterus.
The cervix joins the uterus to the
vagina and seals off the uterus
during pregnancy.
Semen passes through the cervix
from the vagina.
The vagina is the receptacle for the
penis during copulation and serves
as a passageway for the liquid
waste expelled from the urethra.
The vulva is the exterior opening of
the female reproductive tract.
Heat Detection and
Importance of Timing in
Artificial Insemination
Successful and practical AI requires
that a producer be able to detect
females in heat.
Detecting Heat
Females in heat are under the
influence of a sudden, high-level
occurrence of a sex or “heat”
hormone called estrogen.
The egg-containing follicle that
produces the hormone is at the
height of its growth.
The nervous system is greatly
affected.
The producer that knows his
females well can often recognize
heat by the alert, bright-eyed,
nervous appearance shown during
this period.
The female is excitable and may
make an unusual amount of verbal
“calling out.”
She is restless and often walks the
fences.
Standing to be mounted is the only
reliable, practical test for heat.
When a cow stands to be mounted,
she is in heat and is ready for
service.
Ruffled hair over the tail head
suggests that a cow has recently
been ridden, but she may or may
not have been in heat.
When cows “sniff around” one
another, it is a common sign that
one is approaching or is in early
heat.
Riding follows and then the cow in
heat stands to be mounted.
Many heifers and cows in heat flatten
themselves down in the loin region,
giving a “sway back” and “high tail
head” appearance.
Genital mucous (caused by estrogen)
may flow from the vulva in long
strings and wet mucous smears are
often noticeable on the buttocks, over
the pin bones, and under the tail.
The vulva of a female in heat
appears somewhat swollen and the
skin becomes moister and less
wrinkled, whereas a female not in
heat has a vulva that is sunken in
appearance with dry skin and tiny
folds and wrinkles.
The second or third day after heat,
but sometimes earlier, bloody
mucous passes from the female’s
vulva and may be smeared on the
buttocks or tail.
Bleeding from the cow means that
she has been in heat (ovulation
implied) two or three days before.
Whether a female bleeds or does
not bleed after heat has nothing to
do with whether she has conceived
or has not conceived from service
or insemination at that heat.
Heat Detection Procedures
The herd management conditions
determine the exact procedures
to be followed in observing the
individuals of a herd for signs of
heat.
This should be done at least twice
each day.
Animals in pasture must be carefully
observed.
A record-keeping system that tells
when particular animals require
watching helps in detecting females
in heat.
Adequate pens and holding facilities
are very important in an AI program.
The Importance of Timing
in Artificial Insemination
It must be understood that the
female is only fertile when an egg
that can be fertilized is present.
Likewise, it must be understood
that an egg can live only a short
time after being released from the
ovary unless it is fertilized.
The optimal time for insemination
is in advance of the time of
ovulation, which varies according
to species.
This is so the sperm have ample
time to migrate to the oviducts
(infundibulums) by the time the
egg arrives.
The time differs among species.
Mares normally ovulate 24-48 hours
before termination of the heat
period.
A mare with a 5-day heat period
should be inseminated on the third
day and at least every other day
thereafter for the duration of the
heat.
Cows normally ovulate to 10 to 14
hours after the end of heat.
Cows should be inseminated during
the latter half of the heat period.
Ewes ovulate near the end of heat
and should be inseminated during
the last day of heat.
Sows ovulate about 30 to 40 hours
after the beginning of the heat
period.
Sows should be inseminated 12 to
24 hours after the beginning of heat
and serviced a second time 12 to 24
hours later to increase conception
and litter size.
The following factors influence
conception rate and should be
considered in an AI program.
• For highest conception rates in
cattle, breed 60 to 90 days
after calving.
• Best results are obtained if cattle
are bred 12 to 18 hours after
beginning of estrus.
• Sperm live approximately 24 hours
in the female reproductive tract.
• True heat is demonstrated in
cattle when a cow will stand for
others to ride her.
• Fertilization will occur immediately
if sperm are present when the
egg is released.
The Insemination of
the Female
Cleanliness during all insemination
manipulations is essential and is the
crucial point for success or failure.
This applies to the instruments
used, to the hands of the operator,
and to the animals.
Preparing the Semen for
Insemination
Handling and thawing the frozen
semen are critical steps in
preparing the semen for
insemination.
The following precautions should
be carefully taken.
• Care should be taken in handling
the semen straws because
exposure of frozen semen
samples to air for more than 20
seconds may lower the fertility
of the semen.
• Always wear gloves when
handling frozen semen as there
is a small hazard of frostbite
and some straws, because of a
faulty seal, explode rather
violently when thawed.
• Thaw water should be 35°C to
37°C (95°F to 98°F) and the
semen straw should be put
into the thaw water with not
more than three seconds
exposure to air.
• Frozen semen can be warmed
rapidly without harm as long
as the temperature does not
rise above that of the body.
Thawing rapidly in warm water
provides the best sperm
survival rate.
However, straws of semen
should be used within 15
minutes after thawing.
Inseminating Technique
The procedures used in artificially
inseminating female animals vary
with the species involved.
Differences among species in the
cervix openings affect the
techniques used to insert the
inseminating tube.
Artificial Insemination in Cattle
The recto-vaginal technique can
be used with cows (and mares).
In this method, one hand is
inserted into the rectum to
manipulate the cervix through
the rectal wall and the other is
used to direct and control the
inseminating tube.
The arm inserted into the rectum
is covered with a rubber glove or
disposable plastic glove-sleeve.
Most inseminators prefer to use
the left hand for manipulation of
the cervix and the right hand for
directing and controlling the
inseminating tube.
The human hand working within
the rectum must respect the
physical makeup of the tissues
and organs that are contacted.
The technician must realize that
serious damage will be done to
the rectal wall, ovaries, or
uterus when these structures
are improperly handled.
Lubrication of the hand and arm
is very helpful.
Water is sufficient or a mild
lubricant such as K.Y. Jelly may
be necessary.
Soaps or detergents are not
recommended because they are
sometimes irritating and may
harm the sperm.
The technician’s hand should be
entered into the rectum by holding
the fingers in a coned position and
inserting the hand through the anal
opening.
The entire hand and as much of the
arm as is needed can be passed
into the rectal cavity.
The cervix is located, held and
manipulated through the floor
of the rectum.
The other hand introduces the
inseminating tube, or pipette,
(a 5 to 6 mm diameter tube
that is 40 cm long and contains
1 ml [cc] of diluted semen)
through the vagina.
The hand within the rectum
manipulates the cervix to permit
the passing of the tube into the
cervix.
In the cow, the semen is
deposited in the uterus.
The tube tip should not enter into
one of the horns of the uterus, as
it could result in the semen being
deposited in only one horn.
If the cow were to ovulate on the
other side, the sperm would not
reach the ova and fertilization
would not take place.
After passing the inseminating tube
through the vagina and just
through the cervix, the technician
depresses the bulb slowly so the
semen does not adhere to the wall
of the inseminating tube.
The technician withdraws the
inseminating tube and then the arm
and hand slowly from the cow.
Results obtained by using the
recto-vaginal method on cattle
are frequently better than those
obtained by natural mating.
In natural service the bull normally
deposits the semen in the vagina
next to the cervix and the sperm
apparently pass through the
closed cervix with little difficulty.
Presumably, contractions of the
uterus, caused by the hormone
oxytocin, are responsible for the
quick transportation.
It is believed that the sperm must
be in the female reproductive tract
for 4 to 6 hours to develop the
capacity to fertilize an egg.
Because sperm live for only
approximately 24 hours in the
female reproductive tract, the best
time for insemination is between
12 and 18 hours after the
beginning of heat.
A good rule of thumb:
• Cows first detected in estrus in
the morning should be bred
that afternoon; and
• Cows first detected in estrus in
the afternoon and night should
be bred the following morning.
Breeding at this time enables the
sperm to have the ability to
fertilize the egg and remain in
waiting in the oviduct for the egg
to be released from the ovary.
Also important to remember is that
in rebreeding cows after calving, a
60-day rest period should be
allowed for the reproductive tract
to return to normal.
This will improve chances of
conception and lessen the chance
of breeding troubles in the future.
Artificial Insemination in Horses
Artificial insemination with horses
is not as widely of an accepted
practice as it is with other
livestock species.
Some horse breed registry
associations do not permit AI, but
extensive use is made of the
practice known as “impregnation.”
Impregnation consists of collecting
the final portion of the ejaculate as
the stallion dismounts and injecting
it through the cervix of the mare
just covered using a syringe and
inseminating tube.
The purpose of this practice is to
increase the chances of conception.
Horse semen was once considered
to be extremely fragile, but now it
can be effectively stored for up to
24 hours using egg yolk-glucose
extenders and it can be
successfully frozen.
Normally, the semen collected at
one service from the stallion can
be extended to artificially breed
about 15 mares.
For insemination, a glass syringe
attached by a rubber adapter to a
disposable inseminating tube is
commonly used.
The lubricated, gloved hand
containing the inseminating tube
is passed into the vagina.
The cervix is located with the
index finger and the tube is
passed through the cervix.
Insemination is made directly
into the uterus.
The mare has a longer estrus
than other domestic animals.
Some breeders will breed the
mare every other day beginning
2 days after the onset of estrus
(days 3, 5, and sometimes 7).
Some breeders use a method of
rectal palpation to determine the
maturation of the follicle.
Another method used is to
estimate the time of ovulation
from the appearance of the
vagina and cervix as seen
through a vaginal speculum.
It should be kept in mind that
sperm are severely harmed by
water, acids, soap, metals, cold
shock, and high temperatures.
Attempts should be made to avoid
contamination of semen with any
foreign materials and careful
temperature control should be
maintained at all times.
Artificial Insemination in Sheep
The AI technique has not found
wide application in the United
States.
Due to problems with semen
storage, it is necessary to collect
semen from rams when and where
it is to be used.
Vasectomized rams can be used as
“markers” to identify ewes in heat.
Preferably, ewes should be
inseminated during the latter half
of the heat period and while the
vaginal mucous is thin and clear
in appearance.
For insemination, the ewe is
restrained to limit movement and
to present the hindquarters at a
convenient height for easy access
to the vagina.
The cervix is located with the aid
of a speculum and suitable light.
The insemination is made as deeply
as possible into the cervical canal.
When inseminating ewes, 0.05 to
0.2 cc diluted semen, containing 50
to 100 million sperm, is deposited in
the cervix.
Artificial Insemination in Swine
The use of AI in swine is
increasing in the United States and
techniques have been developed
to the point where AI is reliable
and technically simple.
In sows, ovulation normally occurs
about 40 hours after the onset of
heat.
The optimum time for insemination
occurs approximately 16 hours
before ovulation.
This coincides with the time
during heat when most gilts and
sows will tolerate heavy pressure
on the loin area.
Inseminations performed at this
time will result in a farrowing rate
of about 75%, while inseminations
at other times result in a 30% to
40% conception rate.
The technician gently guides the
pipette through the vagina into the
cervix.
When using the pipette, a counterclockwise rotation will insert the
pipette into the cervix.
At this time, the technician can feel
resistance by gently pulling back on
the pipette.
The semen is slowly forced into the
uterus from a plastic squeeze or
syringe.
In swine, 20 to 50 cc of fresh
semen, diluted at a rate of 1 part
semen to 1.5 – 5 parts diluent,
gives reasonable conception rates.
Careful heat checks and patience
during insemination are essential
for good results.
Sanitary Precautions and
Other Management Practices
• Avoid breeding diseased or
infected females.
• Regular examinations of males by
a veterinarian are needed to be
sure they are free of
transmissible diseases.
• Secure a veterinarian to examine
females that have been bred
two or more times without
conception.
• Wait at least 60 days after calving
to rebreed cows.
• Mares can be bred back on foal
heat (7 to 11 days after foaling),
if foaling was normal and no
infection occurred.
• Sows should be rebred in 35 to 50
days.
• All semen collection equipment
should be clean and sterile.
• Follow strict refrigeration
recommendations for handling
semen.
Summary
AI is the process by which sperm
from the male of a species is
collected, processed, stored, and
then artificially introduced into
the reproductive tract of a female
of the same species for the
purpose of conception.
AI is one of the most important
techniques used for improving the
genetic quality of domesticated
animals.
It is a popular technique used by
animal producers, especially with
dairy cattle.
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Instructional Materials Service
Texas A&M University
2588 TAMUS
College Station, Texas 77843-2588
http://www-ims.tamu.edu
2007