**13. Transcervical deep AI**

(the FlatPack®) for freezing boar semen. This package could contain a complete insemination dose, allows a quick and uniform freezing and thawing due to its large surface-to-volume ratio, and fits into any conventional liquid nitrogen container. Nonetheless, insemination

doses per ejaculate. Achieving successful AI with fewer sperm is more important if using

Three techniques of AI can be performed by conventional, intrauterine and deep intrauter‐ ine. The conventional AI is commen in fresh semen practice, while intrauterine with a re‐ duce concentration of semen is increasing with a satisifying result. The deep intrauterine insemination is used for special kind of semen such as frozen semen or sexed semen with a

Conventional AI in domestic pigs is practiced with doses of approximately 3x109 sperm ex‐ tended to a volume of 80 to 100 ml. Semen doses are stored at temperatures ranging 16 to 20°C, usually for up to 3 days in simple extenders, but longer when using other extenders [78,79]. The semen is deposited into the posterior region of the cervix by using a disposable, often an intra-cervical, catheter whose tip stimulates the corkscrew shape of the boar penis and engages with the posterior folds of the cervix as it occurs during natural mating. In gen‐ eral, the AI process starts 12 h after detection of standing estrus and it is repeated every 12 to 18 h until standing estrus is no longer shown. When proper detection of estrus is per‐ formed, the farrowing rate (FR) and litter size (LS) are comparable with those achieved by

Contrary to what occurs in cattle, where FT semen is routinely used for AI [81], cryopre‐ served boar semen is used in less than 1% of the AIs performed around the world. The rea‐ sons behind this restricted use of FT boar semen are the low survivability of sperm after the freeze-thawing process and the shorter lifespan of the surviving sperm. These result in low‐ er FR and small LS compared with AI using semen preserved in liquid form [48]. Further‐ more, owing to the restricted lifespan of the FT boar sperm, excessive sperm numbers are used often 5 to 6 x109 sperm per dose. Moreover, at least two AIs are usually performed per estrus in order to reach acceptable fertility rates in the field [82]. Altogether, few doses can be obtained from a single ejaculate and too many sperm are used to ensure fertilization. A decrease in the number of sperm per dose is therefore required to improve the use of ejacu‐ lates, so that the production will be cheaper and the use of genetically superior sires more

reduce and semen can be deposited near the junction of uterine-oviductal junction.

natural mating, reaching over 90% of FR and mean LS of 14 piglets [80].

sperm per dose, reduces the number of AI

with large numbers of sperm, such as 5 to 6x109

24 Success in Artificial Insemination - Quality of Semen and Diagnostics Employed

Fertility after transcervial deep AI of FT boar semen.

boars of superior genetic merit [71].

**11. Conventional AI in pigs**

**12. Use of FT semen in porcine AI**

effective.

Although few sperm are required for fertilization within the oviduct, this reduced number is the product of a sequential and very effective reduction along the process of sperm trans‐ port in the female reproductive tract (i.e., 25 to 40% of inseminated sperm are lost with the backflow and 50% of the rest of the sperm are ingested by leukocytes in the uterus; Matthijs et al., 2003). The problem to be overcome during AI is to get an adequate number of sperm to the uterotubal junction (UTJ) that could ensure the establishment of the functional sperm reservoir with enough viable, potentially-fertile sperm to ensure maximal fertilization. One strategy proposed to accomplish this is to decrease the number of sperm per AI-dose, by de‐ positing the semen directly in the uterus, and get sufficient sperm into the UTJ. Such deep AI with reduced sperm numbers is a relatively new reproductive practice that has attracted the attention of the swine industry. Such a method could also be advantageous for the spreading of AI with FT semen.

There are basically two non-surgical procedures for depositing sperm into the pig ute‐ rus. These include semen deposition either in the uterine body [49,75,83] or into the uterine horn [84,85].

Intra-uterine insemination (IUI) (Figure 1a)

**Figure 1.** Sperm can be deposited in different procedures: (a) intra-uterine insemination (IUI) and (b) deep intra-ute‐ rine insemination (DIUI)

A non-traumatic transcervical catheter that allows an easy penetration of the cervix and dep‐ osition of semen in the uterine body of the sow has been designed. Briefly, a conventional catheter (outer catheter) is placed toward and locked into the cervix. An inner tube (around 4 mm outer diameter) is passed through the outer catheter, along the cervical lumen, to reach the uterine body or the posterior part of one of the uterine horns (about 200 mm be‐ yond the tip of the outer catheter). The IUI catheter can be used with minimal training and it does not seriously delay the process of insemination, although it can only be safely used in sows [83]. Under commercial conditions, use of the IUI catheter with extended fresh semen can reduce sperm numbers to 1x109 sperm per insemination dose and results in a compara‐ ble effect on both FR and LS (89% FR and 12 LS) compared with 91% FR and 12.5 LS after conventional AI with 3x109 sperm. However, in the field trials carried out by references [86,87], FR were similar between IUI with 1x109 sperm and conventional AI with 3x109 sperm, but IUI sows had significantly less piglets born per litter (1.5 to 2 smaller LS). The reasons for the loss in LS have not been clarified. Rozeboom and co-workers suggested that several factors such as aged sperm, improper semen handling or insemination-ovulation in‐ terval can cause decreases in reproductive performances when low numbers of sperm are used, and in order to obtain consistently high fertility results, a slightly higher number of sperm should be considered.

been suggested that DIUI should be carried out ≤ 8 h before spontaneous ovulation when FT

Improvement of Semen Quality by Feed Supplement and Semen Cryopreservation in Swine

http://dx.doi.org/10.5772/51737

27

In tropical countries including Thailand, cryopreservation of boar semen is nowadays per‐ formed in a very limited scale and it has yet to be conducted for the commercial purpose. Our studies undertaken between 2004 and 2009 therefore aimed to develop boar semen cry‐ opreservation in Thailand. Effects of straw volume, Equex STM paste added to a freezing extender and of the individual differences on boar sperm quality after cryopreservation were investigated. In addition, in vivo fertility results such as fertilization rate, FR and LS of

Using a lactose-egg yolk extender with 9% glycerol as a freezing extender of boar semen, it was demonstrated that after thawing the motility, viability and NAR of sperm evaluated with conventional methods were improved when 1.5% Equex STM paste was added into the freezing media [94]. This finding confirms beneficial effects of the detergent on preventing/ diminishing cell damage during the freeze-thawing process [68,95]. Equex STM paste im‐ proves post-thaw survival of sperm by acting as a surfactant to stabilize cell membranes, particularly acrosomal membranes, and to protect sperm against the toxic effects of glycerol during cryopreservation [73]. However, since the positive effects of this substance are only observed in the present of egg yolk in the semen extender, it is suggested that Equex STM paste exerts its beneficial action through the alteration of low-density lipoproteins in egg

In theory, post-thaw sperm loaded in 0.5-ml straws which have smaller surface-to-volume ratio should not have a better quality than those in 0.25-ml straws. Nevertheless, based on the results of 12 ejaculates from 4 boars evaluated in our study [94], the viability and normal morphology of FT sperm packaged in 0.5-ml straws were superior to those in 0.25-ml straws despite being frozen and thawed with their own optimal protocols. The reason behind this is unknown, but it is interesting that similar results have also been observed in dog semen [96]. Therefore, in order to find the reason and draw conclusions with boar sperm, more in‐

With regard to effect of individual variations on the FT sperm quality, 45 ejaculates of 15 boars from three breeds (Landrace (L), Y and Duroc (D); 5 boars each) were studied [97]. It was found that the breed of boar and the individual boars within the same breed significant‐ ly influenced most of the FT sperm parameters evaluated. For instance, the post-thaw sperm viability in D and L boars was significantly higher than Y boars. The motility and the normal morphology of FT sperm were lowest in Y boars. L boars seemed to have the most varia‐ tions in many of the FT sperm parameters. The difference in sperm quality among individu‐ al boars that was found in our study was in agreement with previous findings [52,98], suggesting that such individual variation may be correlated with difference in physiological characteristic of the sperm plasma membrane among boars. Additionally, the genomic dif‐

**15. Boar semen cryopreservation, experiences in Thailand**

FT boar semen after DIUI and IUI in multiparous sows were evaluated.

yolk rather than directly affects sperm membranes [69].

vestigations in this aspect might have to be performed.

sperm are used [93].
