During sperm collection, the sperm collector holds the false vagina in his right hand and crouches on the right side of the ewe's hip, and the false vagina forms an angle of 35 ~ 42 with the ground. When the ram climbs over, gently pinch the penis foreskin with your fingers and introduce the penis into the pseudovagina. In after ejaculation, the ram slowly climbed down from the ewe, and the sperm collector moved the fake vagina backward, so that one end of the sperm collection cup was downward. Vent from the gas nozzle, take off the cup cover and record the ejaculation volume. (2) Semen quality inspection Normal semen is milky white and extremely thick. Semen with rancid smell and mixed with red and green cannot be used for insemination. At the room temperature of 30℃, the semen was examined with a microscope of 200 ~ 600 times. Dip a small drop of semen in a clean glass rod, put it on a glass slide, and cover it with a cover glass. First, the density is evaluated. If dense sperm is seen in the field of vision and there is no gap, it is rated as "dense"; If a gap about equal to the length of one sperm can be seen between sperm, it is rated as "medium"; If it is longer than one sperm, it is rated as "thin"; No sperm is marked "None". Then look at the vitality of sperm, which is generally divided into five categories: all 100% sperm are advancing in a straight line, rated as 5 points; Every 80% move forward is evaluated as 4 points, and every 20% move down is reduced by 1 minute. If sperm just wobbles or doesn't move at all, it can be marked as "wobbling" or "dead". Only those rated as "Mi ~ 5" or "Mi ~ 4" can be used for insemination. (3) Semen Dilution Because the ejaculation volume of sheep is very small, only about 65,438 0 ml, in order to increase the insemination quantity of ewes, fresh semen is generally diluted to increase the semen volume. The dilution ratio is 1: 2 ~ 1: 4, and the diluents are mostly filtered, disinfected and peeled cattle and goat milk. (4) After insemination, fix the inseminated ewes on the insemination rack, wipe the pudendal parts with small pieces of sterilized gauze, and replace a piece of gauze for each sheep, and then wash and disinfect it for later use.
The inseminator holds the device in his left hand and the device in his right hand, slowly inserts the device into the vagina, gently rotates it, and opens it to look for the cervix. After finding the cervix, gently insert the insemination device into 1 cm, gently push the piston of the insemination device with your right thumb, and input 0. 1 ml semen. After insemination, register the sheep number and mark it.
In order to find the cervix easily and insert the insemination device, headlights, flashlights and other lighting were often used in the past, which was difficult to coordinate and time-consuming and laborious. For this reason, Feng Xufang suggested using the "simple automatic lighting device for sheep artificial insemination" (Figure 3): install a flashlight bead (weld a tin bayonet or stick it with tape) on the inner side of the lower leaf of the opener. Tie a needle on the back of the handle bead and connect the wire to an electrode of the battery. As conductors, the bayonet and opener can be connected with the other pole of the battery through the iron ring and lead on the finger sleeve to make the electric beads glow. If the power supply uses No.5 battery, it can be installed inside the lower petiole of the bottle opener. If the power supply uses the No.1 battery, it can be hung on the insemination rack or put in the pocket of work clothes.
Fig. 3 Simple automatic lighting device for sheep artificial insemination
(5) Semen preservation: put the fresh semen after quality inspection and dilution into a sterilized dry test tube, cover it with a layer of sterilized liquid paraffin, then plug it tightly and gradually cool down. When the temperature drops to 10 ~ 0℃, it can be preserved.
Semen is generally stored at 20℃ for about 6 hours, at 65,438+00℃ for more than 65,438+02 hours and at 4℃ for more than 24 hours. The preservation effect is better at 0 ~ 4℃.
Before using the preserved semen, the temperature must be gradually increased, and the temperature should be checked at 38 ~ 40℃. Only those who pass the test can be fertilized. Sperm is very sensitive to the change of temperature, so it is necessary to prevent the sudden change of temperature during storage, so as not to affect its vitality. The diluted semen needs to be cooled to storage temperature above 1 hour. Whether it is heating or cooling, it is advisable to change 5℃ every half hour.