How to inseminate your pig
A pig farmer who considers him/herself to be in the business of producing pigs should ensure that he or she develops the technique of Artificial Insemination (AI). AI is the deliberate introduction of semen in its fresh or chilled state in the vagina of the sow. A good quality boar could be used however; there are a number of advantages in practicing AI which makes economic sense:
- AI decreases the numbers of boars needed by a farmer. Fewer boars mean less feed and maintenance costs.
- It is a safe method of introducing new genes into pig herds.
- Semen from a range of top-performing tested boars of several breeds is available from specific farm stores
- The genetic influence of good boars can be spread more widely.
- There is less risk of introducing exotic diseases with AI than in the importation of live pigs.
- It may be used during temporary shortages of boars from death, lameness or failure to work.
- It allows the mating of animals of different sizes. eg, older, larger boars can be "mated" to smaller gilts when employing AI
Equipment needed for Insemination
Catheter (A flexible tube inserted through a narrow opening into a body cavity). The catheters commonly used for AI are the reusable rubber 'Melrose' with spiral tip or disposable plastic catheters having several types of tip. All are easy to use and achieve good results.
Semen bottles or tubes
Chilled semen bought from farm stores comes in ready-to-use inseminating bottles or tubes. But if semen is collected and used fresh or diluted on-farm, a supply of clean plastic inseminating bottles will be needed.
Care of equipment
Since boar semen is an excellent medium for growing bacteria, all AI equipment must be kept clean. Immediately after use, soak reusable equipment in cold water so that semen or other material is easily removed later. Do not use soaps or detergents because they affect sperm viability. Particles of gel can be removed with a brush.
When to inseminate
With the absence of a boar the farmer is required to monitor his animals to detect when the sow/gilt comes on heat. There are some physical signs that the farmer will observe:
- In a group, the sow mounts others while swelling and reddening of the vulva (in gilts especially) gives early warning
- Some sows may honk, lose their appetite and appear nervous, thus signaling approaching
oestrus. This period before oestrus proper lasts 2 to 4 days.
- The vulva is red and swollen and watery mucous is often seen after sexual stimulation. Peak fertility is in the middle 24 hours when the inseminator can get a strong 'standing' reaction (starts about 12 hours after onset of oestrus). The swollen red vulva has noticeably subsided by this. Mucous is plentiful and has better lubricating qualities than that seen at the beginning of oestrus. The colour of the mucous changes from clear to greyish-looking at this stage.
How to Inseminate
- Thirty minutes before use, remove the chilled semen bottle from its pack and allow the semen to warm up.
- 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 infectious material into the uterus and also provides sexual stimulation.
- Manually stimulate the sow to induce the mating stance. This is done by applying pressure between her shoulder and mid-back, knee pressure to her flanks.
- Gently guide the catheter, with the tip pointed up, through the vagina to the cervix. Attach the bottle to the end of the catheter and discharge the semen slowly. A gentle squeeze to start the process may be needed, but after that the semen should be allowed to be taken up by uterine contractions.
- When the sow is well stimulated, insemination should only take 5 to 10 minutes. It is possible to let the semen gravity-feed into the catheter when using soft-walled bottles; gentle pressure may be used with any type of bottle, particularly the firmer types.
- Watch for catheter blockages and semen back-flow. If an excessive amount of backflow occurs, stop. Either the semen is being deposited too rapidly (the semen needs to be deposited at a slower rate) or the catheter is not locked into the cervix.
- When all of the semen has been deposited into the female, remove the catheter by rotating it clockwise while gently pulling. Some people prefer to leave the catheter in place for several minutes to prolong cervical stimulation.
- A new catheter should be used for each insemination to eliminate the possibility of transmitting a disease or infection from one female to the next.
- Keep the female in quiet surroundings for 20-30 minutes. Distress at this time may still disrupt semen transport and fertilization.