The Use of AI in swine Reproduction

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The Use of AI in swine Reproduction

• Dr. Jeff Clapper
• South Dakota State University

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Advantages of AI

• Allows more extensive use of older boars on
  lighter weight females.
• Decreases the number of boars and time required
  for breeding when estrus is synchronized.
• Promotes development of a closed herd.
• Allows introduction of new genetic material into
  a herd with minimum risk of disease.
• You know that semen is alive because you can
  examine it.

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Disadvantages of AI

• AI requires a higher level of management in order
  for it to be effective.
• Risk of disease is of greater importance because
  a diseased boar could spread this to 15 - 20
  females.
• There is an increased margin of error brought
  about by the human factor that may lead to
  reduced reproductive performance.
• It is easy to become complacent when things are
  working well. This can lead to cutting corners
  and a decrease in reproductive performance.

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Ovary - Uterus - Cervix
Uterine Horn
Uterine Body
Ovary
Endometrium
Interdigitating Pads
Cervix
Bladder
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Utero-Tubal Junction
Mesosalpinx
Isthmus
Tip of Uterine Horn
Ampulla
Utero-Tubal Junction
Ampullary-Isthmic Junction
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Boar Anatomy
Cowpers Gland
Seminal Vesicles
Sigmoid Flexure
Bladder
Cauda Epididymis
Retractor Penis Muscle
Ductus Deferens
Testis
Glans Penis
Caput Epididymis
Pampiniform Plexus
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Estrous Cycle

• Non-pregnant and non-lactating sows and gilts
  display estrus regularly throughout the year once
  they have reached puberty.
• The estrous cycle is approximately 21 days (range
  of 18 24 days) in length and is defined as the
  time between the onset of one estrus to the onset
  of the next.
• Lactation inhibits the estrous cycle and sows
  will not return to estrus until weaning.
• However, days from weaning to estrus can be
  influenced by length of lactation, parity, season
  and nutritional level. The normal weaning to
  estrus interval ranges from 4 to 7 days.

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Estrous Cycle

• As estrus approaches, 6 10 follicles form on
  each ovary. Follicle stimulating hormone (FSH)
  stimulates the growth of these follicles at a
  rapid pace for about 3 days prior to estrus.
• Cells within each follicle secrete estrogen which
  causes the typical signs of estrus in the female.
• Ovulation, or release of the ova from the
  follicle, is stimulated by luteinizing hormone
  (LH).
• Ovulation occurs about 40 hours after the onset
  of estrus but this interval is variable.
• Several factors can influence the number of ova
  shed or ovulation rate.

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• Generally sows will ovulate 18 20 ova while
  gilts may ovulate 12 14 ova. Flushing
  (feeding increased energy levels prior to estrus)
  may increase ovulation rate but usually has
  little effect on litter size. The white or
  maternal breeds usually have a higher ovulation
  rate than the colored or terminal breeds.
  Crossbred females generally ovulate more than
  either of the parent breeds.

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Trait Large White Meishan F1 Cross
Born Alive 9.8
13.2
13.8 Ovulation Rate 14.9
18.9
17.7 Prenatal Survival () 66
71 78 Piglet
Birthweight (kg) 1.28 0.93
1.20 Number of teats
14.2 17.3
16.3
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Estrus

• The onset of estrus and estrus behavior occurs
  gradually and individual females may respond
  differently.
• The classic or primary sign of estrus in the gilt
  or sow is standing to be mounted by the boar or
  another sow or gilt.
• Many sows and gilts will also stand for the back
  pressure test when applied by a stockman.
• However, a higher percentage of females will
  stand immobile for the stockman if a boar is
  present.

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Effect of Stimuli to Elicit Immobilization

• Stimulation estrous sows standing
• Boar 100
• Boar back pressure 97
• Boar (hidden) back pressure 90
• No boar (NB) back pressure (BP) 48
• NB BP boar courting sounds 75
• NB BP preputial secretion 80
• NB BP 5 alpha androstene 81

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Estrus

• Some of the secondary signs of estrus include
  red, swollen vulva (more so in gilts than sows),
  increased nervous activity, seeking the boar,
  loss of appetite, mounting other females.
• Length of estrus is variable and may last only 12
  hours in gilts or up to 60 hours in sows.
• After ovulation the follicles are transformed
  into corpora lutea (CL).
• The CLs produce and release progesterone from
  about day 5 postmating until day 16 17 if the
  female is not pregnant.
• At this time prostaglandin F2? is released from
  the uterus and the CLs regress (die) and another
  set of follicles begin to grow and the whole
  process is repeated.

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Estrus Detection

• The single most important component of any AI
  program is proper estrus detection.
• The onset ovulation begins between 36 and 44 h
  after the onset of estrus and lasts for 1 3
  hours.
• There can be considerable variation in the
  duration of standing estrus within a herd. There
  may also be differences from farm to farm and
  genetic differences in the duration of estrus.
• Females tend to ovulate at a time which is about
  2/3 of the period of standing estrus.
• Using a boar with the backpressure test is one of
  the most accurate methods of finding females in
  estrus.

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Estrus Detection

• Housing should facilitate boar exposure but
  restrict nose to nose contact because this leads
  to habituation.
• The presence of the boar increases the chances of
  detecting all females in estrus by 30 40.
• Ideally the gilt should be kept in a crate where
  the boar can have direct nose to nose contact as
  he walks in an alley in front of the gilts.
• Restrain the boar in front of a focus group of 4
  5 females at a time.

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Estrus Detection

• Estrus detection should ideally be performed ½ to
  1 hour before or after feeding twice a day at
  700 AM and 500 PM or as close to the end of the
  work day as possible.
• The more frequently estrus detection is done the
  better the chances of inseminating at the correct
  time.
• Use of an old smelly boar that produces lots of
  saliva is best. Nose to nose contact is
  essential because the boar produces a pheromone
  in the saliva that helps to initiate the standing
  reflex in the female.
• The standing reflex involves prolonged
  contractions of the skeletal muscles much like
  isometric exercises.

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Estrus Detection

• After 5 10 minutes the female becomes fatigued
  and becomes refractory to the boar stimulus or
  back pressure stimulus for a duration of 1 to 2
  hours even though she is in estrus.
• Sperm can remain viable within the female
  reproductive tract for 24 hours, however, there
  is a gradual loss with time. Eggs are only
  viable for about 6 hours or less.
• The goal of each manager is to devise an estrus
  detection and insemination program that will
  provide an adequate number of viable sperm near
  the site of ovulation 6 10 hours prior to
  ovulation.

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When to Inseminate

• Based upon 2X/d estrus detection
• If sows are in estrus 3 -4 d PW, wait 24 h to
  inseminate, then inseminate 12 h later.
• If sows are in estrus on d 5 PW, wait 12 h to
  inseminate, then inseminate 12 h later.
• If sows are in estrus 6 -7 d PW, inseminate
  immediately, then inseminate 12 h later.

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When to Inseminate

• If 1X/d estrus detections are performed then the
  sow should be inseminated immediately upon
  detecting her in estrus and then in 12 h.
• Inseminations should continue for every day that
  she is in estrus but no more than 3 times.

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When to Inseminate

• Double matings are superior to single matings in
  terms of litter size and conception rate.
• If gilts exhibited estrus for 2 d then double
  matings increase farrowing rate and litter size.
• The number born alive is more related to multiple
  matings than is farrowing rate.
• Semen to be used should be between 36 -48 h old.

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Sources of Semen

• Over 50 different suppliers of boar semen are now
  available to the producer. Semen is collected
  and shipped fresh and extended to the customers
  door via UPS or Fed Ex at a cost of 20 - 40.
• Contract Semen Customer signs a contract with
  semen supplier to use a specified amount of semen
  each week. This is very cost effective for very
  large producers that breed a large number of
  females each week.

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Sources of Semen

• Semen from a Particular boar - Generally this is
  the most costly and ranges from 20 - 60/dose.
  Delays can occur if semen is sought from a
  popular boar.
• Special mixed Semen - This is a mixture of semen
  from many different boars of the same breed. Not
  as expensive as from a particular boar.

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Sources of Semen

• Mixed Semen - This is a mixture of semen from
  many different boars of different breeds. This
  tends to be the least expesnive and could be used
  in generating terminal line of commercial pigs.
• Left Over Semen - This is semen that is left over
  from a collection and has not been sold. This is
  then sold at a discounted price.

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Sources of Semen

• All semen should be stored in the dark at 62 -65
  F (17 C). Semen in extender can last as long as
  7 d, but it is best to use it as soon as
  possible.
• Semen in extender should be gently rotated twice
  a day to ensure mixing of semen with extender.

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Training Boars for Semen Collection

• Select a person who is patient and enjoys working
  with animals.
• Begin training during the isolation process by
  building a trust between you and the boar. Spend
  a few minutes each day scratching, rubbing and
  talking with the boar.
• Boars vary in their rate of sexual development.
  Some 7 mo old boars are ready to be trained and
  others require 4 - 6 wks longer.

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Training Boars (cont)

• Provide a clean, dry, well lighted area free of
  distractions. A breeding mat helps provide
  footing. A boar that slips during mounting may
  be shy about attempting it again.
• Keep the area about 8 x 10 ft, so that the boar
  is focused.
• If possible, collect a previously trained boar
  first. The odor and sound may stimulate the
  rookie if he is located next to the collection
  area.

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Training Boars (cont)

• Adjust the dummy so that it is equal to or
  slightly lower than the boar being trained.
• Plan for short training sessions (15 -20 min).
  Some boars may mount the dummy immediately but
  others may want to explore the pen and dummy for
  several session.

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Training Boars (cont)

• Some boars require coaxing. Crouch down near the
  dummy, allow the boar to smell your hand and
  clothes and talk in a reassuring tone. Try
  pouring semen from a previous collection on the
  dummy.
• Keep the boar focused on the dummy. If needed,
  use winged gates to keep him in front of the
  dummy.

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Insemination Process

• Move the boar in front of 2 -3 estrus females to
  be inseminated. Make sure the female is exposed
  to the boar before beginning the insemination.
• Clean the vulva with a clean dry paper towel.
• Part the lips of the vuvla with one hand and
  gently insert the catheter into the vagina
  pushing forwards and upwards for the first 6 -8
  inches. Advance until resistance is felt.

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Insemination Process

• If using the golden pig catheter, push the
  catheter into the cervix and you will feel it pop
  in.
• If using a spirette or tother threaded catheter,
  turn it counterclockwise to enter the cervix. It
  will flip back when twisted counterclockwise when
  it is locked in.

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Insemination Process

• Get the semen from the storage container and
  resuspend by gently rotating the bottle or
  cochette.
• Cut off the tip of the bottle or open the
  cochette and place on the catheter. Lift the
  catheter and apply gentle pressure to fill the
  catheter and begin the insemination.

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Insemination Process

• Begin rubbing the underline to stimulate uterine
  contractions.
• Normal services take 5 - 10 min gilts may take
  longer. You may have to tip the bottle down to
  slow the insemination.
• Once the container is empty it can be removed.
  Dont force air down the catheter.

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Insemination Process

• The catheter can be removed by clockwise rotation
  of the spirette or by gently pulling on the foam
  tip type.
• Check the tip of the catheter for blood and
  record if found.

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AI Tips

• If the female lays down during insemination,
  continue with procedure as she lays down.
  Slapping her to get her up inhibits the release
  of oxytocin and uterine contractions.
• Sows may pull the semen from the bottle faster
  than needed, lower the bag or bottle to slow
  deposition of the semen.

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AI Tips

• If the bottle of semen is collapsed and still has
  some semen left in it, remove the bottle and
  allow it to re-expand with air and then reconnect
  to the catheter and finish.
• Bend the catheter to prevent the backflow of
  semen after insemination and continue to rub the
  underline.