1. - INTRODUCTION: Natural reproduction is still the most widely used practice in the world of production in birds but artificial insemination is taking an important role in recent years. Natural reproduction has the advantage of economy of labor but also has major drawbacks, which is why so artificial insemination starts playing with his own name. Disadvantages of natural reproduction found the birds need to be exploited on land (together) with what this entails: increased food consumption and health conditions worse, the lighting conditions are not the most suitable for sperm production and finally is very difficult to select genetically fittest males for reproduction or even try to select certain characters.

While it is true that many of the disadvantages of natural reproduction are eliminated in artificial insemination, because the players are staying in different places in order to achieve the ideal conditions in each case (better sperm production, more eggs, less food consumption, increased disease control).'s not all advantages in artificial insemination, and they reside in the higher cost of labor and the need for increased investment in accommodation, facilities, etc ....

Despite the possible disadvantages of artificial insemination is amply demonstrating a technique that eventually gives much better results in production levels and that is why it is slowly making its way into poultry production.

2. - METHODS OF OBTAINING THE SEMEN

2.1-SEMEN COLLECTION: Among the most common and effective methods for obtaining semen is the dorso-abdominal massage milking sewer, described by Burrows and Quinn (1935) and is currently the most popular birds like roosters, turkeys, pheasants, raptors, and even columbiformes small sized birds such as finches.

Another method used in ducks and raptors is the collection with artificial vagina subject to the availability of a female stimulating or raptors for the animal is imprinted.

Regardless of the technique used is always needed training before implementation.

2.1.1-SEMEN COLLECTION THROUGH MASSAGE: This technique requires the hand of two people. One is performing the massage in dorso-abdominal region and holds the male, after two or three strokes of the hand the bird lifts its tail and cloaca shows very evident with semieversión penis, you press the region sewer lateral, where sperm vesicles are getting the expulsion of semen. That's when the second person must collect semen avoiding aspiration parallel catch urine, feces, etc ... as these fluids have adverse effects on sperm quality and sperm fertilizing power obtained.

2.1.2-SEMEN COLLECTION USING A STIMULATORY FEMALE: Obtaining semen by stimulating a female is the most used in ducks, the males staying in individual cages, they are presented to stimulate a female and if the female is receptive and sexually active male, courtship occurs rapidly. It is then going to produce copulation when the operator must exit the penis by a slight pressure above the sewer with the subsequent erection of this and the subsequent departure of semen. To train these males should begin at the time they begin to be sexually active.

For imprinted raptors which acts as a stimulus for the male sex, it is the breeder (master falconer), although the mechanism by which this stimulation occurs in the bird is not very clear, the technique is to rapacious climb above the kind of cap which is put on the head and the breeder acting as semen collection mechanism.

3. - EXPERIMENTAL ANALYTICAL FRAMEWORKS

3.1-INSEMINATION MATERIALS: Several possibilities insemination with semen pure previously diluted semen. When the seed used is pure and therefore quickly applied to the female sperm is maintained in the collection tubes themselves provided they are not contaminated by feces, urine, etc ... In the case where the diluted semen must the preferred method is to collect semen in the tubes containing the diluent. Insemination is usually done with graduated syringes fitted with a suitable cannula to breed the species, so we apply the exact dose but should be taken to change the cannula in each animal inseminated with the sole purpose of not transmitted from one individual to other pathogens. There are vending machines, equipped with disposables, you can distribute the semen in straws calibrated and used with an "insemination gun" avoiding the possible transit of germs between animals and secondly applying the exact dose insemination.

We have also in some species as in the case of chickens suitable instrument for holding females (clamping plates or tablets) that allow a single operator to different inseminate hens of the same battery.

3.2-PLACE INSEMINATION: Undoubtedly inseminations can be performed in different parts of the female genital tract, giving very high fertilization rate made in the vagina, uterus, ovary magnum and even using thawed semen. But usually inseminations performed at the level of the vagina as elsewhere insemination may require the need for surgical techniques resulting in a loss of productivity. The results obtained by performing inseminations vagina level differ considerably depending on the depth at which this takes place. The practice leads to the conclusion that the best part of insemination is the middle of the vagina to minimize the maximum expulsion of sperm and not damage the utero-vaginal.

3.3-INTERVALS INSEMINATION: Unlike mammals, birds sperm are able to survive in the female genital tract and retain their fertilizing ability for much longer. This period offers a wide variability of one species to another (21 days in chickens, turkeys 60 days, 16 days in canaries) which determines the frequencies of artificial insemination. The conservation of the spermatozoa is given by tubular glands "sperm nests" found in the infundibulum and the utero-vaginal sperm that provide appropriate biochemical conditions.

Clearly the durations of these periods in which sperm are kept alive in the female genital tract ("fertile") vary with the females and their physiological state, thus contributing to the state of egg formation in relation to the insemination, age and also vary according to the number of inseminated spermatozoa and the quality of these.

The highest fertilization rate in chickens is obtained on the second day after insemination and this is maintained near this level ("plateau") for a week on average in the various races, decreasing rapidly as the sigmoidal curve for be negligible at 20 days after insemination. All species of birds exhibit this sigmoidal curve type, ranging from one to another duration "plateau level".

We conclude that in order to produce an optimal level of fertilized eggs must be performed inseminations in a time interval not exceeding the durations of the plateaus of each species (leg :2-6 days, painted: 5-7 days, turkey :7-21 days).

3.4-TIME INSEMINATIONS: It has been found that successful insemination is related to the cycle start condition of the female in the time of application of the sperm. The presence or absence of eggs, the presence of secretions, etc ..., influence the transport and storage of the sperm.

However, when insemination occurs can be masked when using large doses of spermatozoa, which makes setting the insemination dose.

In the case of hens inseminated advised about 8 hours after lights to the roost, whereas in the case of turkeys and guinea insemination should be done very beginning of the light period or just before they go off lights.

3.5-RELATIONSHIP BETWEEN THE NUMBER OF SPERM INSEMINATED AND FERTILIZATION RATE: The importance of the insemination dose lies in the number of spermatozoa inseminated and the fertilizing capacity of these. Thus, for example higher dose volumes give very similar results with a smaller volume dose but with the same quantities of sperm.

Something that is clear is that when very high dilutions are decreasing the fertilizing capacity of sperm motility decreased, so it has been found that when the sperm count is 100-120 million sperm per dose ( in chickens), results are achieved up to 96 100 fertilization rate does not increase if further increases the number of sperm inseminated.

Also keep in mind that as females are becoming older, larger doses are necessary to arrive insemination have to inseminate doses of 250 million to 300 million spermatozoa and in some cases. In all other avian species insemination doses are very similar and in the case of the kettle is recommended inseminate start before the start of the laying period, as the first inseminations are always worse than the rest.

 

4. - TECHNOLOGY OF SEMEN

4.1-DILUTION OF FRESH SEMEN: The problem of whether or not to dilute the semen is related to the time that will elapse until it is used. In cases in which the semen is used in 30-45 minutes after collection, it is necessary to dilute. But when the time is up is essential dilute while refrigerarlo.En collected even if turkeys or guinea fowl rapidly loses its fertilizing power and that is why so diluted. On the other hand, can not be said that diluted or not semen, inseminate does not allow a greater number of females because as discussed above the important factor is the number of sperm per insemination dose.

4.2-THINNER FEATURES: The thinner must be able to preserve the fertilizing capacity of sperm, buffered medium acidification due sperm metabolism, provide energy type nutrients at certain times and preparing for sperm freezing. In the case of the diluted semen is used without being frozen, can be used diluents favoring buffers fertilizing capacity of sperm. Phosphate buffers sodium type to be discarded while the TES can be used if used at a concentration of 65g / l to ensure an osmotic pressure of 380-400mosm / l. Among the most commonly used diluents, we find Sexton Lake or osmolarity compliant and further include up various buffer systems (citrate, acetate, BES, or TES), also have very specific concentrations of electrolytes and chelators and generally carry a sugar (fructose in the case of glucose Sexton or Lake.

Despite the complexity of some of these diluents is not clear that the single TES better conservation of fertility. Van Wambeke proposes using a diluent with milk and egg fertilization rates of up to 92-99 percent, this being a widely used diluent for semen of birds of prey.

4.3-DILUTION RATE: As discussed above further dilution does not increase the fertility rate but on the contrary, excessive dilution may lead to reduced motility and a decrease in the fertilizing power of sperm. The dilution rate should be fair to bring all the advantages of the dilution. Thus the appropriate level of dilution is usually between ½ and 1/3 for the different species.

4.4-TERM USE OF DILUTED SEMEN: Usually the term for using fresh semen is around 24-48 hours but this variation is given by a number of factors such as:

4.4.1-Semen quality before dilution.

4.4.2-semen oxygenation during storage.

4.4.3-The temperature at which the semen is stored (6hrs, turkeys 12-15 ° C)

4.4.4-The cooling rate for storage (ideally 1 ° C / min) All variations of these factors will impair lesser or greater extent the storage time for subsequent insemination sperm.

4.5-FREEZING OF SEMEN: Besides the significant economic cost that this technique involves adding the low fertilization rate achieved, so it is not a technique with a great future in poultry production (low cost of chicks). Conversely, if a technique is to consider that much interest in sports poultry (pigeon, etc ...) and of course in the world of biopreservation (use in endangered species). The difficulties arise when conducting the freezing sperm birds are on the one hand, the deterioration in the sperm membrane causes the appearance of microcrystals and dehydration during the preparation process and by other phenomena toxicity also caused by freezing.

Prior to freezing the sperm should suffer a preparation at a temperature of 4 ° C, then is diluted semen gradually to add one or more cryoprotectants (glycerol, DMSO, dimethylacetamide). With the use of cryoprotectants water solidifies in the amorphous state in order to avoid the appearance of microcrystals but these do not attain their maximum function if high concentrations are not made to destroy the sperms.

Freezing as such occurs with nitrogen vapors after semen has been distributed in straws, ampoules or tablets and storage and preservation is done with liquid nitrogen. The major problem of these steps is to avoid the formation of microcrystals maximum.

Another phase which is very delicate defrosting is, it must be rapid to limit the growth of microcrystals and it must be replaced by one diluent insemination glycerol. After replacing the diluent should perform the insemination.

5. - BIBLIOGRAPHY:

1. - BERNARD SAUVEUR, MICHEL DE Reviers.; Bird reproduction. (Carlos Buxadé CARBO, Spanish version)
2. - FERNANDO OROZCO, breeding poultry. Agroguías University Press.
3. - E.BLESBOIS, F.SEIGNEURIN, I.GRASSEAU, C.LIMOUZIN. Semen cryopreservation for ex situ management of genetic diversity in chicken: creation of the French avian criobank. Poultry science: http://ps.fass.org/ cgi / content / full / 86/3/555
4. - H.M. PARKER and C.D.McDANIEL,. Semen dilution prior analysis influences the Ability of the sperm quality analyzer to predict fertility inseminating with a constant Whether number of esperm or a constant volume of semen. Poultry Science.
5. - Y.Y. ZHANG, characterization and esperm sperm storage in Cabot's Tragopan.
6. - ROBERT B.BERRY, Reproduction by artificial insem