Artificial cold blending technology is a cattle breed improvement technology that is currently being promoted. It uses frozen beef semen from foreign beef breeds (Angus, Simmental, Limousin, etc.) to accurately determine the cow's estrus period and optimal insemination period. Based on the artificial insemination method, the female animal is made pregnant.
First, the cow's estrus performance
1. Early stage of estrus: The cow buzzed and his appetite began to subside. He wanted to climb across the cow, but refused to cross the bull. The vulva was slightly red and swollen. The vaginal mucous membranes were congested and a thin, transparent liquid emerged. Rectal examination of the uterus becomes soft, one side of the ovary increases, there are follicles in the ovary, inelastic. This period of maintenance is about 10 h, can not insemination.
2. In the middle of estrus: The cow is extremely uneasy, the appetite stops, the libido is vigorous, the eagerness is sought, the cow is straddled, the genital area is swollen, and the mucus overflows. Rectal examination of the uterus is soft, the volume of follicles increases, diameter 1.0? -1.5?, Outstanding on the surface of the ovary, elasticity, a sense of volatility. This period of about 8h-12h, early insemination.
3. Late stage of estrus. Cows lose their libido and no longer cross their cattle. From restlessness to quietness, genital swelling decreases, mucous thickens, yellow-white. Examination of the cervix by rectal examination revealed that the cervix became soft and the wall of the follicular wall became thin. The fluctuation was very obvious. It was ripe grape-like and had a feeling of touch. This period of about 8h-10h, the best insemination period.
Second, estrus identification
The estrus identification was based on the combination of external observation and rectal touch follicles, and the rectal examination of follicles was the main criterion.
1. External performance: When the estrus cows turn into the late stage of estrus, the cows are quiet, their appetite is gradually returning to normal, and when other cows cross over, the buttocks are evaded, the vulva swollen and the wrinkles gradually recede.
2. Mucus: vaginal mucosa is dark red, mucus is small, mucus is turbid or grayish white.
3, rectal examination: rectum touch the uterus, ovary, determine its length, thickness, texture. The sequence is: wearing latex gloves and applying lubricity agent. Put the five fingers together and extend into the anus. After removing excrement, the palms are stretched and the palms are down. In the middle of the pelvic floor, there is a long, slightly flat stick for the cervix. Walking forward along the cervix, you can touch the uterine horn groove. On both sides of the sulcus, there is a cylinder bent forward. It is the left and right uterine horns. To oblate, soft and elastic ovaries. The degree of follicular development on the surface of the ovary was touched with a finger to determine if insemination.
Third, the best insemination period
It is the most appropriate time for the insemination of cows after estrus. This is the key to improving the conception rate of females. The average female steak time is 12-15 hours after the end of the cow's estrus, and it takes about 6-12 hours for the discharged eggs to reach the site of fertilization. The time for maintaining the fertilization capacity is generally not more than 20 hours. After insemination, most spermatozoa require 2-3 hours to reach the site of fertilization, 5-6 hours for energy gain in the cow's reproductive tract, and approximately 30 hours for fertilization. Therefore, spermatozoa should reach the site of fertilization before the egg to obtain the best conception rate. It is generally believed that the timing of insemination is 6-18 hours before ovulation and the conception rate is high. However, it is not easy to grasp the time of the female steak, and in the production practice, comprehensive analysis can be made.
1. Plan to inseminate twice. The first time after the cow refuses to climb, the first time, the interval is 8-12 hours for the second time. It is also possible to climb in the morning, inseminate in the afternoon, and reconstitute once in the morning on the next morning; in the afternoon, insomnia in the morning and in the afternoon, it will be repeated once in the afternoon. If only one insemination is performed, it can be performed 8-12 hours after the refusal to climb.
2, from the vagina out of mucus thick, yellow, block, the cervix outside the mouth is a little tight and hard, the inner mouth soft insemination device is easy to insert infusion, interval 8-12 hours second insemination.
3. When the rectum touches the ovary, the wall of the ovary becomes thin, and the follicular fluid fluctuates obviously. If there is a feeling of touching, the spermatozoa can be inseminated, and insemination is repeated every 8-12 hours.
Fourth, artificial cold matching technology
1, equipment preparation
There are 1 straw infusion gun and thermometer, 1 for scorpion and thin tube, 1 for nail clipper and 1 for constant temperature water bath.
2, fine tube freeze thawing
The temperature of the water bath to adjust the temperature 40 °C -42 °C, with tweezers from the liquid nitrogen tank to remove the fine tube of frozen essence, can not pull the thin tube bag out of the liquid nitrogen tank, the tube into the water bath shake 10-15 Second, make it warm evenly. Dry the straw with a paper towel with good water absorbency, check the type and type of the semen you are taking, use the end of the thin tube tampon as the bottom, lift it by hand and flush it with the eye, cut off about 0.5 cm of the closed end, and cut it to the right , Sections should be completed, cut a complete round incision, and then loaded into the insemination gun for use.
3, insemination method
Rectal grasping the insemination method. Before insemination, the cow to be bred should be placed in a breeding rack, and the feces and dirt near the vulva should be rinsed with warm soapy water, and then rinsed with warm water. The inseminator cuts his fingernails short, wears latex gloves on his arms, applies a layer of lubricant, puts his fingers together into a cone, inserts the rectum, and excretes feces. Hold the cervical canal across the rectal wall. The left arm presses slightly to open the vague door. Hold the vas deferens (gun) in the right hand, insert slowly from the vulva, begin to incline slightly upwards, avoid the urethral opening, and then insert the cervix into the cervix, insert the end of the vas deferens deep into the cervix to the mouth 3?-4?(about 2 -3 wrinkled walls) The spermatozoon (gun) can be inseminated after pulling it slightly, and the insemination tube (gun) can be pulled out slowly after insemination.
4, matters needing attention
4.1 Freezing essence is examined at a temperature of 38°C to 40°C. If the microscopic examination activity is less than 0.3, insemination is not allowed.
4.2 Rectal examination or insemination, when the cow blames and the intestine becomes empty, do not grasp hard.
4.3 Winter insemination should prevent cold attacks on semen after thawing.
4.4 Immediately after thawing, insemination should occur and semen storage should not exceed 1 h.
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