Compiled & shared by-DR RAJESH KUMAR SINGH, JAMSHEDPUR, JHARKHAND,INDIA
9431309542,rajeshsinghvet@gmail.com
Source–Dr Nihar Ranjan sahoo, M K Patra, Rajveer Maurya, G K Das and G K Gaur
Swine Production Farm, LPM Section
ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, UP-243122
What is artificial insemination (AI) and why in swine—
Artificial insemination (AI), the placement of spermatozoa into a female genital tract using artificial means, is the oldest breeding technology used since 1900s. In pigs this has been used since the early 1930s worldwide, but its commercial use has taken off only now in our country. In this process semen is collected from a male, evaluated, processed, and deposited inside the reproductive tract of a receptive female by means of a catheter.
It has got several advantages like—
AI facilitates genetic improvement by producing maximum number of offsprings of desire trait in least possible time.
Owing to the high cost involved in supply of superior breeding male to each village, delivery of semen from superior male through AI is suitable and viable alternative.
Genetic improvement can be achieved at a faster rate using artificial insemination technology.
This can be used effectively for female with unequal size or problems in hind legs and create less stress on gilt/sow.
Further, it helps in prevention of transmission of venereal diseases.
Selection of breeding stock——————-
Selection of breeding boar for AI is of paramount importance as that determines the quality of the piglets to be produced to a large extent.
Males having weaning weight of ≥10 kg (42 days) may be initially selected. Body weight gain of such selected males should be >250 g daily.
Should have sound feet with good, full hams, uniform curve at the back and of good length
The toes and pasterns should not be very long, weak or misshapen (No stiffness or lameness).
The testes should be normal in shape and size, even, and free from any defects like criptorchidism.
Libido and overall activeness/alertness should form final basis of selection
Training of boars———————–
The training of boar for donating semen is the most vital part in the complete process of AI. Regular training of boar with great patience is utmost important for success.
For training, breeding male should be housed individually.
To begin the training, the boar should be taken to the collection room or pen once to twice daily to make him acquainted with the dummy sow.
The semen collection pen may be constructed adjacent to the boar stud or by connecting through a direct passage up to the boar pen.
The collection pen and its surrounding area should not have any materials that can distract the boar and divert the focus of the boar away from the collection dummy.
The recommended floor space for collection pen is 48 to 72 sq feet.
Collection of semen————————–
Many boars mount the dummy sow during one of the first few training sessions. The boar under training should be exposed to the dummy sow immediately after collection of semen from an already trained boar.
In case, a boar that does not mount after two or three exposures to the dummy, semen from another boar can be sprinkled or urine or vaginal mucus from estrus female can be sprayed on the dummy. If the boar is interested in the dummy and/or has mounted the dummy, then the boar should be approached quietly from the rear without being touched or frightened.
Once properly stimulated, the boar extends its penis and become very quiet if adequate pressure is applied on penis and soon it starts to ejaculate semen. Semen can be collected from a trained boar by glove hand techniques.
Pig semen is very sensitive to cold shock. To avoid any damage due to cold shock while collection, the semen should be collected into a thermos flask or a sterilized bottle with heat protected cover.
The gel portion of the ejaculate should be filtered out during collection using sterilized gauze putting into Buchner funnel or by using filter paper. After collection, the semen should be transferred to the laboratory for routine evaluation of quality and processing.
Semen evaluation and processing —————————–
Routine evaluations of sperm motility, concentration and live – dead count of ejaculate should be done to either accept for further processing or to reject. Trained personal or veterinary professional, binocular microscope and minimum laboratory facilities viz., glass slides, cover slip, different stains and few glass wares and plastic wares are required to carry out the evaluation process.
Depending on the semen volume and concentration, it can be extended with suitable extender (BTS extender or Premix-cell extender, IMV, France) at the ratio of 1:3 to 1:4.
Before dilution of semen, the semen and extender are brought to the body temperature. After extension whole amount is kept for 1 hour for equilibration and thereafter packaged in to golden tip bag (GTB pouch, IMV, France) or plastic container with cap for approximately 80 ml per dose.
The GTB bag can be sealed effectively using a plastic sealing machine and is need to be stored at 15- 18°C in BOD incubator for about 2 to 5 days.
Signs of estrus———————–
The detection of heat/ estrus is an important step determining the success of the artificial insemination in pigs. The observable signs for detection of heat are given as follows.
Reddening of vulva
Vaginal discharge
Frequent urination
Lack of appetite
Restlessness
Mounting over other females
Stand still when pressure applied on the back
Estrus detection should be accurate and insemination is to be done at correct time.
Time of insemination——————————-
The spermatozoa takes 24 hours or more to reach in the oviducts after copulation. The viable life of frozen and thawed spermatozoa is only about 8 to 10 hours in the oviducts, whereas the eggs or ova are viable for less than 6 hours in the oviduct. Ideally, eggs should be fertilized within hours of being shed.
Inseminations with fresh or chilled semen achieve optimum conception about 12 hours before ovulation. Since ovulation follows onset of heat after about 40 hours the best insemination time is 28 hours (about a day) after onset of heat.
As the exact time of oestrus onset is difficult to pinpoint on-farm, inexperienced persons particularly, should perform two inseminations 12 hours apart to achieve the best results. If only inseminating once, it should be done within 24 to 32 hours after the onset of ‘standing’ heat.
In practice, where checking for ‘standing’ heat twice daily, inseminate the sow about 24 hours later after checking the sow whether receptive or not with the back pressure.
Insemination techniques————————–
The right technique for insemination is an important element which determines success of AI. The technique should imitate the natural mating as closely as possible.
Golden sow or gilt catheter can be used for insemination. Before inserting the catheter, clean the sow’s vulva and the area around it with a fresh, damp cloth or paper towel. This reduces the chances of introducing any infectious material into the uterus and also provides sexual stimulation.
The sow could be brought into the mating stance by manual stimulation. This is done by applying mild pressure between her shoulder and mid-back, knee pressure to her flanks and massaging her vulva and udder.
Lubrication of the tip of the catheter with a small amount of semen or B-Lube gel makes it easy to insert the catheter into the vagina.
Part the lips of the vulva and gently insert the catheter upwards into the vagina and gently pushed through until resistance is felt at the opening of the cervix. Spiral tipped catheters are rotated anti-clockwise and steadily pushed to lock into the cervix. As the cervix of a sow in oestrus is firm and well lubricated the inseminator can apply positive pressure while ‘locking-in’ the catheter.
Once the catheter is locked in the cervix, the semen package is squeezed slowly and gently to pass into genital tract in gravitational force. Once sow is well stimulated, insemination should only take 5 to 10 minutes.
If the catheter is not far enough in or the inseminator is too hasty, back-flow may occur. When this happens, disconnect the bottle, reposition the catheter and delay the insemination for a minute or two. Semen is often squeezed out by abdominal pressure when the sow moves suddenly.
After semen enters the sow’s reproductive tract, sexual stimulation should continue for several minutes. This ensures that the uterus contracts actively to generate forces for passage of the spermatozoa towards the oviducts, where fertilization of the eggs takes place.
While removing the catheter, ensure the free end is higher than vulva. Allow the sow to remain undisturbed following insemination.
For diagnosis of pregnancy, female should be observed for next 21 days for detection of estrus following insemination. Non-returning of next heat is considered to be the early sign of pregnancy.
Cautions—————–
Human error in collection, processing, and preservation of semen, heat detection and insemination may lead to failure in getting desire conception rate. Therefore, necessary training needs to be undertaken before initiation of the artificial insemination activities.
