To increase the fertility rate of sows and increase the number of embryos, it is not only necessary for boars to provide excellent quality sperm, but also for sows to discharge more fertile eggs, and for sows and sows to mate at suitable times so that most or all of the eggs are laid. Have the opportunity to be fertilized. This is the key to determining the level of conception and the number of litters. For this purpose, the ovulation law of sows should first be mastered, and then based on the time when the sperm and egg germ cells maintain fertilization within the reproductive tract of the sow. (1) Regularity of estrus after sows giving birth After sowing, the sows usually have three estruss within a short period of time: the first appears in 2-7 days postpartum, the estrus symptoms are not obvious, can not be normal ovulation, is a estrus infertility; the second occurrence of estrus in the postpartum 22 ~ 32 days; symptoms are not obvious, but if the breeding can be fetus, it will not affect lactation and calving performance, is a breeding time should be used; the third is 3-7 days after weaning. According to statistics, under normal feeding and management conditions, among the large group of sows, after 8 days of weaning at the 35th day of the piglet, 85% of the sows in heat within 7 days are the breeding opportunities that must be seized. (b) Ovulation of estrus sows After the sow reaches sexual maturity, there will be regular sex cycle. In the sexual cycle, the estrus is the climax of the sex cycle. During this period the sow receives the boar's crawling and mating, and is also the duration of the ovulation of the sow. During this period of time, the sow is only bred or inseminated. Therefore, it is an important period for the sow to accept the boar cross-breeding period. As for other estrus symptoms, they are all symptoms of estrus. The time when the estrus's sow receives the boar's climb and the length of the duration of the climb is related to the type, breed, age, feeding and management conditions of the pig. (c) timely breeding It was observed that the longest survival time for spermatozoa in the sow reproductive tract was 42 h, but the time for the sperm to be fertilized was only 25 to 30 h. The sperm was fertilized in the sow reproductive tract after 2-4 h. This is what is commonly referred to as "sperm capacitation," and only the sperm that are capable of fertilization can bind to the egg. The egg is excreted from the ovary and enters the tubal enlargement through the umbrella; the sperm and the egg can only be fertilized if they meet at this site. The time for the egg to pass through this part of the fallopian tube, which is the time for the egg to maintain its fertilization capacity, is 8 to 10 h and can be up to 15 h. If the egg is not fertilized in the swollen part of the fallopian tube, it will continue to move along the fallopian tube to the uterine horn, and the egg will gradually age and be trapped by the fallopian tube secretions, hindering the sperm from entering and losing fertility. Tests have shown that spermatozoa reach the inside of the sow's fallopian tube for a very short period of time. After being capacitated, the ability to fertilize is much longer than when the egg is fertilized. Therefore, before sows ovulate, it is necessary to breed or inseminate several hours before the peak of ovulation, that is, 2-3 hours before ovulation, or 12 to 24 hours after the start of estrus. Wait for the arrival of the egg. Due to differences in ovulation time of different breeds, ages and individuals, it is important to be flexible when determining breeding times. From the species point of view, local porcine species in our country have a long duration of estrus and are late in ovulation, and can be bred in the first 3-4 days of estrus. The introduced estrus has a short duration of estrus, ovulation is earlier and can be bred on the second day of estrus. Hybrid pigs can be bred on the afternoon of the second day or on the third day after estrus. From the age point of view, the introduction of pig-type young sows during the estrus period is shorter than that of the old sows; while the local varieties in China are the opposite. From this we can see that the mating experience of "early match with old, small match with late, and not many with middle" is only in line with the law of ovulation in the estrus of Chinese pig breeds. Judging from the estrus performance, the sow’s mental state is from restlessness to a daze (hands pressed against the waist and buttocks), and the vulva is swollen from red to pale and wrinkled. When the mucus becomes thicker from the water, it means that it has reached the fitting period. When the vulva mucous membrane dries and refuses to match, the fitting time has passed. At present, it is advisable to adopt a method of breeding or inseminating twice during the estrus period so that during the ovulation, there will always be energetic sperm waiting for the arrival of eggs at the fertilization site. The precise timing of two breedings or inseminations during an estrus period varies slightly depending on the breed type, age, and feeding and management conditions of the pig. It is generally believed that estrus sows will be breeding for the first time between 8 and 12 hours after receiving a boar cross, and will be bred for the second time every 12 hours, and the conception rate and litter size will be better. Wheeled Hose Reel Cart,Hose Cart With Wheels,Large Hose Reel Cart,Garden Hose Cart With Wheels NINGBO QIKAI ENVIRONMENTAL TECHNOLOGY CO.,LTD , https://www.hosereelqikai.com