Which AI technique is most effective?
José Antonio García Ruvalcaba, DVM, MSc
Technical Director Asia-Pacific
Europolis, Las Rozas (Madrid). SPAIN
Artificial insemination (AI) is a reproductive method that is used worldwide by the benefits it represents, however this technique is not always used in the best way possible due to the peculiarities of each pig farm and various factors that influence. In recent years a new technique has been developed; the so call post cervical artificial insemination (PCAI) which represents some theoretical advantages when compared to the conventional or intra cervical technique of artificial insemination (CAI), however, it has been demonstrated that with the use of both techniques, excellent reproductive performances can be achieved. The purpose of this presentation is to explain which are the main differences between both techniques and under which circumstances are recommended.
It is considered that the main objective of artificial insemination (AI) is to ensure that a minimum concentration of spermatozoa (spz) reaches the fertilization site during the pre-ovulatory period in a female to obtain a high fertilization rate, thus to increase the farrowing rate and litter size. The PCAI technique is of more recent implantation compared to the CAI technique, its development and implementation at farm level was during the decade of the nineties in certain European countries moving its influence in countries of the American continent later and more recently in Asia. Although its use is currently widespread and it is a relatively easy reproductive technology to apply, some critical points should not be forgotten to consider in order to maximize its effectiveness.
Critical points of CAI and PCAI
The main advantage of the PCAI is the possibility of depositing the semen closer to the fertilization site, avoiding volume losses due to backflow and therefore the possibility of reducing both the volume of the semen dose and the concentration of spz that represents a reduction in the inventory of boars needed for AI, resulting in a more effective genetic improvement when using elite boars and a reduction of costs. These advantages are not always achieved if the critical points of this technique are unknown.
The use of PCAI compared to CAI avoid the transit of spz trough part of the female genital tract (cervix), ensuring that an optimal functional sperm population reaches the oviduct at the time of ovulation. The anatomical structure of the cervix acts as a barrier that with the CAI technique requires contractile stimuli to allow the spz to overcome this structure and reach the body of the uterus. This situation requires that the insemination with CAI has to be performed in the presence of a boar that through its physical contact, olfactory (pheromones), etc. stimulates the standing in heat and immobility reflex in the females and the release of oxytocin necessary to produce contractions that facilitate the transit of the spz.
On the contrary with the PCAI there is no need to use boar stimulation during insemination; it is counterproductive since a relaxed cervix is required. With PCAI, the boar should only be used during estrus detection but not during the insemination process, thus reducing contractions of the cervix what facilitates the introduction of the internal cannula. It is advisable a waiting time between the estrus detection and the insemination that as a minimum must be between 45 to 60 minutes to allow another receptive period in the female.
Hygiene is another important factor to consider, with both techniques, however with the PCAI these measures must be maximized; in fact this is one of the most important critical points to take into account and that depending on the level of the farm serves as a decision making to decide which technique to apply. With PCAI we are penetrating a place of "non-physiological" insemination since in natural mating the penis of the boar and the uterus of the female are designed so that the deposition of the semen is at the level of the cervix, acting the cervix as a natural barrier to prevent the passage of microorganisms that can contaminate the uterus, therefore with PCAI it is necessary to use material as sterile as possible and that the cleaning procedures prior to...
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