Frozen semen transport and preservation 1. Semen should be sourced from a regular supplier, select good varieties that are suitable for local growth and market demand, and the quality of semen should meet the requirements of national standards. 2. When moving the liquid nitrogen tank, you should grasp its handle, gently handle it, prevent it from tilting, and protect the vacuum pumping valve. When transporting, lay thick cushions, fix them properly, and install them in thick cartons or wooden boxes according to the conditions of transport. Securely attach them to the vehicle to avoid bumps. 3. During the preservation of frozen sperm, the status of the liquid nitrogen tank should be checked frequently. If abnormal liquid nitrogen consumption is found to increase significantly or the container is exposed to frost, it should be replaced immediately; when the liquid nitrogen capacity is less than 1/2, add it in time. The minimum liquid nitrogen content can not be lower than 1/3 of the total volume of the tank. The remaining amount of liquid nitrogen can be estimated by the weighing method. It can also be inserted into the bottom of the tank with a fine wooden stick. After 10 seconds, it is taken out according to the measured length of the frosting line. estimate. 4. When picking and placing frozen semen, only mention the bucket or package of frozen semen to the base of the neck of the container. Do not mention the outside of the neck. The movement should be rapid. If it has not been taken out after 10 seconds, it should be replaced. Submerge in liquid nitrogen and continue to pick and place; when the stored frozen sperm needs to be transferred to another container, the residence time outside the container must not exceed 5 seconds. If it takes longer, it should be handled in a container filled with liquid nitrogen. Estrus identification and timely insemination Estrus identification 1. External performance. Mainly according to the external performance of the cow to determine the degree of estrus, determine the breeding time. When the cows are in estrus, they are mentally disturbed, yelling loudly, squeaking and rubbing each other, placing the neck on another cow's back, doing some intimacy, sniffing the cows of other cows, swelling of the labia, and vaginal outflow. The sticky mucus. 2. Vaginal examination. This method can not accurately determine the ovulation time of cows, only as an auxiliary method. Early: vaginal mucosa was pink, dull, with a small amount of mucus, slightly outside the cervix to carry out; middle: stick out of the sticky glass, labial lax swelling, vaginal mucosa was red, there is a strong luster and smooth feeling, mucus often with Bloodshots, swelling of the cervix, loosening, opening, cervix slightly open, labia swelling; end: mucosal color lighter, thick mucus, uterine contraction and swelling wrinkled. 3. Rectal examination. Rectal examination is a relatively accurate and commonly used method to determine cow estrus. At the beginning of estrus, the follicle begins to develop, and the volume increases. When touched, only the softening point of the bean size is felt; the follicles of the mid-term increase rapidly, the surface of the ovary is smooth, the wall of the ovary becomes thin, and there is a slight sense of volatility. The duration is about 10 hours to 12 hours. During the prosperous period of estrus, the volume of follicles no longer increased, the walls of the follicles became thin, and there was a clear sense of volatility. The estrus symptoms of the cow gradually disappeared from the faintness. At this time, the fertility rate of the insemination was the highest; at the end of the estrus, the follicles burst and the fluid lost. The formation of a small depression, 6 hours to 8 hours after ovulation began to form the corpus luteum, and protruding from the surface of the ovary, this time can not touch the ovulation depression. Timely insemination The timely insemination time of a cow depends on its external appearance and changes in follicles. Practice has shown that the best effect is in the end of estrus or near the end of estrus. In order to improve the conception rate, in practice it is recommended to perform insemination twice within 1 episode, with an interval of 8 hours to 12 hours. Correctly master the insemination technology Strict disinfection The operating room should be kept clean and ventilated, with good light and dust-free ground. To prevent mosquitoes, mice, rats entering the room, indoor timing ultraviolet lamp or 0.1% benzalkonium bromide solution disinfection; insemination site with 0.1% benzalkonium bromide solution to wet, to prevent dust from flying. Before insemination, the cow's vulva and its surroundings are scrubbed with 0.2% potassium permanganate solution and then wiped with a dry towel; the insemination equipment can be disinfected with high-pressure steam or 75% alcohol, and then rinsed with normal saline. Insemination operation To achieve slow insertion, depth, light transmission, slow stroke, to prevent semen backflow. Specific methods: Before the hand reaches into the rectum, put on gloves, apply lubricant or soapy water, keep the hand of the insemination gun as dry as possible, and merge the left hand into a conical shape and enter the rectum to determine the part of the cervix and gently grasp Live it. Then wipe the vulva with a paper towel or a cotton ball and insert it 45 into the insemination gun. Gradually rotate the insemination gun to make it in a horizontal position. This will avoid entering the urethra or bladder; continue to inseminate. When the gun is stretched forward, when it feels elastic, it stretches the uterus forward, stretches the vaginal folds forward, and feels obvious friction, indicating that it has reached the cervix; holds the cervix and cooperates with both hands to make the insemination gun. Into the cervix, pay attention to the cervix is ​​the highlight of the vagina, therefore, it is necessary to move the insemination gun back a little, and use the thumb and forefinger to hold the back of the cervix, the thumb root and the little finger may close the cervix in order to find Quasi-cervical ostia and smooth access to the cervix duct; the passage through the cervix is ​​not smooth, if the insemination gun is obstructed by the cervix ring, gently move the insemination gun back a little, with both hands, insert again, can not The insemination gun is forced through the cervix. For older cows, sometimes the uterus has fallen into the abdominal cavity, and it must be lifted up so that it is in line with the sperm insemination gun. In cows, Insemination guns may not be completely through the cervix, when Insemination gun reaches the deep cervical or uterine body, to insemination. Strengthen the breeding and management of frozen herds Scientifically raising cows, keeping cows in a medium condition, increasing light before estrus occurs, strengthening exercise, increasing the supply of protein feed, ensuring vigorous reproductive function, promoting egg production and excretion, preventing embryonic death; strengthening cow pregnancies The post- and post-production rearing management can increase the energy supply in the feed and increase the post-natal period conception rate. At the same time, the strengthening of feeding and management is of great significance for the identification of whether or not to be affected by fetuses, prevention of misfits, and miscarriage. Do an early pregnancy test to reduce abortion After the cows are mated, they should do a good job of pregnancy inspections in time to prevent the cows from emptying, to continue breeding the cows without the conception, and to strengthen the feeding and management of the cows that have already undergone fetuses, and do a good job in protecting the tires. The general performance of cows after pregnancy is: stop estrus, docile temperament, increased appetite, better body condition, smooth hair, and cautious behavior. Two months later, the uterine horns on both sides of the rectum examination began to be asymmetrical. The gestation angle was approximately two times larger than the empty angle. The basal wall of the gestational angle was soft, and there was fluid flow without contraction. The ovary was soft and smooth, and the uterine artery began to pulsate. Empty corner base wall is hard, no liquid flow is touched, ovary texture is hard, uterine artery has no pulse. Strengthen the feeding and management of pregnant cows. Do not use laxatives or drugs that cause uterine contractions when using drugs. Exercise should be moderate to prevent excessive labor, startle, kicking, and reduce miscarriage. Sodium Erythorbate Fcc Grade,Sodium Erythorbate Powder,Sodium Erythorbate Food Additive,Food Grade Sodium Erythorbate SHANDONG BAISHENG BIOTECHNOLOGY CO., LTD , https://www.baishengbioproducts.com