The obtaining of excellent results in porcine insemination is conditional to a combination of the following factors:

• the use of well-preserved quality semen;
• the rigourous practice of a good detection of the oestrus of the females and the presence of the boar; and
• putting the semen in place at the right time according to the established rules.

Prevervation

The fresh semen from the boar must be constantly maintained at a temperature set between 15 and 18 degrees Celcius (60 and 65 degrees Fahrenheit) so it may keep its fertilization power. It must also be protected from daylight. In these conditions, it will be able to maintain its fertilization power up to four days after the removal, and even more in the case of the " prolonged preservation ".

One must be certain that, at the farm when the inseminations are received, these specifications are strictly observed (i.e.: La Réception de la semence, Courrier CIPQ, vol. 3 no.1).

The turnover of the doses helps to preserve the quality of the semen. To be efficient, the turnover must be done at least twice a day. The automatic turnover system " Spermix " has been especially designed with this in mind. The turnover must definitely not be continuous.

Detection of the in heat periods

The verification of the in heat periods of the sows should start the day following the weaning. Even if a very limited number of sows is in heat this early, this would have a stimulating effect which would shorten the interval weaning-oestrus.

The sows should be placed in a well lit environment (at least 300 Lux). The duration of the light period is equally important and should be 16 hours or more.

The weaned sows should be nourished at will, from weaning to covering, in order to stimulate their rate of ovulation.

The detection of the in heat periods must be done everyday, the ideal being twice a day with an interval of at least 8 to 10 hours between each. The presence of the boar is essential during this operation. The more the sows are exposed to the elements related to the presence of the boar (sight, smell, sound and direct contact), the more they will show the characteristic immobility reflex associated with the oestrus.

The signs related to the oestrus of the sow are the following: red swollen vulva, flow of mucus, loss of appetite, distinctive grunting, nervousness, looking for the boar and the immobility reflex and distinctive positioning of the ears toward the back when there is dorsal pressure. These signs are not always simultaneously present and only the immobility reflex, also named the cavalier's test or straddling, constitutes the point of reference of the detection of in heat to determine the ideal moment to do the insemination.

Favorable conditions for insemination

The right synchronization of insemination relative to the ovulation of the female is of prime importance to obtain excellent results in terms of the rate of conception and the size of the litter. The ovulation of the sow lasts approximatively twelve hours. Research on the subject has demonstrated that it started following the manifestation of the immobility reflex; in fact, it happened at the second third (66 to 70%) of the period of receptivity to the boar. During the ovulation, the spermatozoa, which have a life expectancy in the genital tractus varying from 24 to 72 hours, should already be at the site of fertilization.

The difficulty in the choice of the favorable period for insemination resides in the fact that the sow's receptivity period to the boar varies in duration. Generally this period lasts approximately 48 hours, but certain groups of sows show a longer duration (3 days or more) and others (like the young sows) a shorter duration (24 to 30 hours). Dr Weitze's work has made a relation between the duration of this receptive period and the interval weaning-oestrus (ISO) evident. Females showing a short ISO (3-4 days) generally express a longer duration of receptivity to the boar, therefore later ovulation after the start of this period. Inversely, the females that show a long ISO (7 days and more) manifest a short period of receptivity to the boar and, consequently, an early ovulation.

In order to correctly hit the moment of ovulation, it is recommended to proceed with two inseminations at intervals from 12 to 24 hours. The following chart illustrates the procedure generally used for two inseminations.

ISO (days)	Duration of in heat period (days)	1st A.I.	2nd A.I.
		(hours after the start of immobility to the boar)
3-4	3	24	48
5-6	2	0	24
7 and more young sows	1	0	12

In the case where one makes two detections a day as recommended, and the duration of the receptive period is at least two days, it is suggested that the first insemination be delayed by half a day. The second insemination will then be realized 12 hours after the first one instead of 24 hours.

It is important to check the receptivity of the sow before each insemination and each day until it does not show any more immobility reflex. If the in heat period lasts longer than the normal duration, a third insemination becomes necessary. The rule to be applied in this case, is to make an insemination for each day the sow shows the immobility reflex in the presence of the boar.

One must never inseminate a female which is no longer in oestrus. The natural defense mechanisms of the sow are not efficient anymore and it would result in an important increase of risk of infection of the uro-génital system.

How to inseminate

Insemination of the sow

1. Make sure that the female is in heat when the overlaping test or in presenting the sow to the boar.
2. Prepare the material necessary for insemination.
3. Warm the semen according to the method described in " Warming of the semen, Pros and Cons "Réchauffement de la semence, le Pour et le Contre" ". The duration of the heating of a dose must not exceed 15 minutes.
4. Wash the sow's vulva with type ? disinfectant soap.
5. Always use disposable paper towels. Dry with another dry towel.
   
6. Introduce the insemination probe delicately into the vagina, point the former upward to avoid the external orifice ot the urethra. Push lightly on the probe screwing toward the left (counterclockwise) until it fits solidly into the cervix. Always manipulate the probe in a way to prevent contamination of the section entering into the vagina. To do so, use the disposable wrapper of the probe.
7. Delicately shake the semen.
8. Cut the end tip of the semen tube with a blade or scissors.
   
9. Affix the connecting tube to the insemination probe.
10. Set the other end of the connecting tube to the insemination probe.
11. Apply light pressure on the semen tube to drive the air out of the probe till the semen begins entering the uterus.
    
12. Stimulate the female during the insemination by dorsal pressures or the use of a detection saddle. The aspiration of semen must last at least three minutes. Slow down the aspiration if needed by lowering the semen tube to the level of the vulva. To accelerate, lift the semen tube over the level of the animal.
13. Wait about two minutes after complete discharge of the semen into the uterus to take out the probe and throw ir away.