Artificial insemination of pigs is an important technology in modern animal husbandry and an important means to accelerate the development of animal husbandry. In 2007, the state began to implement the subsidy project for improved pig varieties, and vigorously promoted the artificial insemination technology of pigs in key counties across the country, making the technology rapidly popularized. However, due to various reasons, some sows return to love after mating, which directly affects the economic benefits of pig farmers. Combined with many years' practical experience, the author briefly analyzed the reasons of sow's emotional recovery after artificial insemination and the countermeasures to be taken. Keywords: sow; Return to love; Reason; Countermeasures 1 reasons for returning to love 1. 1 poor semen quality 1. 1 irregular semen production. In the process of sperm collection, irregular operation often leads to abnormal sperm. In the process of dilution, the large fluctuation of temperature difference will also lead to the increase of sperm mortality. In addition, semen is too diluted to reach the standard of 3 billion sperm. 1. 1.2 When semen is stored improperly, the temperature in the incubator is abnormal, the semen is not rotated in time, and the semen is stored for too long, which leads to the decrease of sperm motility. 1. 1.3 Problems in semen transportation in high-temperature and low-temperature seasons, due to improper heat preservation and heatstroke prevention measures during bus consignment, sperm often die, and poor road conditions in some towns and villages are easy to lead to sperm vitality decline or death. 1. 1.4 Other factors affecting sperm survival Water, smoke, light and radiation all affect sperm survival. 1.2 improper operation by the breeder 1.2. 1 failed to grasp the breeding opportunity. The best mating time for sows should be about 6 ~ 18 hours before ovulation. If it is too early, either the sow's cervix is not opened and the semen cannot enter the uterus; Otherwise, when the sperm reaches the fertilization site, it is still early from ovulation, and when the egg is discharged, the sperm has lost its fertilization ability. If the mating time is too late, or after the egg is discharged for a period of time, the sperm has not been capacitated, and after the sperm is capacitated, the egg has lost its fertilization ability. It's too late to mate, because the cervix is closed and semen can't enter the sow's uterus. At present, most large-scale pig farms implement artificial insemination technology. Because the breeder is careless and neglects to observe the estrus of individual pigs, or the estrus symptoms of individual pigs are not obvious, and the insemination is too late, the eggs discharged by sows are aging because they cannot combine with sperm for a long time, resulting in infertility of sows. Due to the uncertainty of sow estrus in rural free-range farmers and the poor grasp of breeding time of breeding pigs, the pregnancy rate is not high. 1.2.2 The pregnancy rate is not reliable because sperm motility is not checked before mating and mating is not strictly in accordance with the quality standard of insemination semen. Some artificial insemination stations do not carefully check the quality of semen, and only infer the quality of semen after treatment according to the normal results of several inspections. Sometimes, they only check the diluted semen. Some semen has exceeded the normal storage period and its vitality is already very low, so it is still used for insemination. 1.2.3 Pay attention to cleaning the sow's vulva before mating hygiene, but it is not recommended to wash it with clean water, but to wipe it thoroughly with dry disinfectant paper towels. However, some pig farms go through the motions to clean the sow's vulva without careful operation. In artificial insemination, if you touch the front end of the vas deferens and the foam head with your hands, it may pollute the vas deferens and cause uterine inflammation. In addition, the sanitary condition of the breeding house floor is also very important to keep the sow vulva clean. 1.3 sow 1.3. 1 There is no limit on feed after mating: usually, the daily feed intake of sows is limited to 1.5-2.2㎏ within 4 weeks after mating. Excessive feed, vigorous metabolism of basic energy and imbalance of endocrine in sows cause changes in intrauterine environment, which interferes with implantation of fertilized eggs and leads to reduction or reversal of pregnancy. Overweight or underweight sows: There are more adipose tissues attached to the uterus or ovaries of obese sows, which leads to the stop of follicular development or the limitation of uterine function, which is not conducive to the implantation of fertilized eggs. Sows are too thin, and fertilized eggs are not easy to implant. Feed mildew: feeding moldy feed leads to embryo death. Management stress: such as heat stress, high temperature leads to the increase of uterine temperature, which is not conducive to the formation and implantation of fertilized eggs. At the same time, the increase of blood flow on the sow's body surface under high temperature leads to insufficient blood supply to the uterus and embryo death. Usually, the estrus rate of sows in June, July and August is the highest in the whole year. Stress factors such as rack biting, hurdle moving and transportation will affect the endocrine state of sows. For example, when biting the rack, the secretion of adrenaline in sows will be excited, which will affect the survival of embryos.

1.3.2 sow disease sow endometritis: sow endometritis is the main cause of sow infertility. Inflammatory secretion of uterus hinders the movement and survival of sperm, making it impossible for sperm to reach the fertilization site; Salpingitis or edema, pyorrhea and ovarian adhesion can all cause tubal atresia and infertility. Some sows are infected with germs due to irregular operation during insemination, and the breeder brings germs into the uterus of sows, or the uterus is infected with germs during estrus, causing metritis. Some sows are often infertile due to reproductive diseases, and breeders should know the situation in time. Such sows are not suitable for breeding and should be eliminated as soon as possible. Reproductive disorders of sows: such as porcine highly pathogenic blue ear disease, classical swine fever, porcine pseudorabies, porcine parvovirus disease, etc. There are many factors that lead to the change of heart of sows after mating. In order to reduce the occurrence of back feeling, comprehensive measures must be taken, starting from the technical level of breeders, disease control, feeding management, environmental control and so on. 2. 1 semen quality is the basic standard for using semen: the dosage of semen is 80 ~ 100 ml, each head contains more than 3 billion effective sperm, and the sperm motility after dilution is ≥0.7. 2. 1.65438+

2. 1.2 Reasonable preservation

After the semen is stored at room temperature (25℃) of 1 ~ 2h, it can be stored in the incubator of 17℃, or it can be stored directly in the incubator of 17℃ with a towel wrapped tightly. The short-acting diluent can be stored for 3 days, the medium-acting diluent can be stored for 4-6 days, and the constant-acting diluent can be stored for 7-9 days. No matter what diluent is used to store semen, it should be used up as soon as possible. Gently rotate once every 12 h to prevent sperm from dying due to precipitation. Pay close attention to the temperature change of the incubator, and try to reduce the number of times of opening and closing the incubator. 2. 1.3 The transportation of shock-proof semen should be placed in a device with good heat preservation. In summer when the temperature is high, ice cubes should be added to the double-layer foam box, and then the semen should be transported to prevent overheating and excessive dead sperm. In cold season, cotton with good thermal insulation effect should be used to keep the temperature at 16 ~ 18℃. Strong vibration should also be avoided during sperm transportation. 2. 1.4 Sperm motility needs microscopic examination. Semen quality should be checked, including semen volume, color, smell, sperm density, vitality, abnormal rate, etc. To ensure the quality of semen is qualified. Sperm motility should be checked after sperm collection, and fresh sperm motility should be ≥0.7. When checking sperm motility, glass slides and cover glasses should be preheated at 37℃. After dilution, it is required to stand for a period of time before sperm motility examination. If the vitality changes little before and after dilution, it can be stored in separate packages. If the vitality is obviously reduced, it should not be used. It is particularly necessary to check sperm motility before mating. Take the semen out of the incubator at 17℃, shake it gently, put 1 drop on the preheated glass slide with a sterilized dropper, put it in the incubator at 37℃ for a period of time, and check the sperm vitality with a microscope. Sperm viability ≥0.7 can only be used.

2. 1.5 The instrument needs disinfection. The laboratory should be neat, clean and hygienic. All utensils should be cleaned with detergent or washing powder, washed with distilled water, and dried at 60℃ (the drying temperature of glassware can be higher than 100℃), and then the opening of the utensils should be wrapped with tin foil, and the glassware should be sterilized with 180℃ 1h in dry heat, and the non-heat-resistant utensils and appliances should be used with1h. 2.2 Practice internal strength and master excellent mating skills. 2.2. 1 Identifying estrus and mating in time is the key. Estrus identification is the premise of timely breeding and the main link to improve pregnancy rate. The key is to accurately estimate the ovulation time. The estrus cycle of sows can be divided into pre-estrus, estrus, post-estrus and inter-estrus. Only in estrus can sows make boars get up or stand up, which can be used as an indicator of timely insemination of sows. The first insemination was carried out at 8 ~ 12h after oestrus sows showed static reflex, and then the second or third insemination was carried out every 8 ~ 12h. 2.2.2 Mastering insemination technology is a means of breeding technology, which is directly related to the conception rate. Anyone engaged in this work must strictly follow the insemination procedure in practice. The procedure of insemination is as follows: ① Disinfect and clean the hands of insemination personnel. ② Wash the vulva, tail root and buttocks of sow, then soak the towel with warm water and dry the vulva. ③ Take out the sterilized vas deferens from the sealed bag. Don't touch the first 2/3 part of vas deferens, and apply lubricant to the front end. ④ Insert the vas deferens upward at a 45-degree angle into the sow reproductive tract. When you feel resistance, slowly rotate counterclockwise and move back and forth until you feel that the front end of the vas deferens is locked (gently pull back), and confirm that it is locked by the cervix.

⑤ Take out the qualified semen from the semen storage box, and confirm the boar breed and spike number.

The article is transferred from the internet for reference only, thanks to the author.

Attachment: sow reproduction

The individual development of pigs originated from fertilized eggs. In order to breed a large number of high-quality piglets, sows must be in normal estrus and excrete a large number of high-quality eggs in addition to obtaining a large number of high-quality semen.

Spare sows can promote sow estrus, including contact with the opposite sex, feeding management, feeding complete feed and paying attention to energy protein balance.

Attention should be paid to the breeding of multiparous sows, and comprehensive diets should be provided during the breeding period to maintain the physical condition of sows. If sows are overweight, they will not be in estrus, ovulate less, and their eggs will be weak and empty. Too thin can also cause postpartum estrus delay and other undesirable phenomena.

In order to breed sows, timely breeding is needed. Sows ovulate 24-36h after estrus, and the ovulation lasts 10- 15h. Eggs can be fertilized in fallopian tubes for 8- 12h, sperm can reach fallopian tubes in reproductive tract for 2-3h, and sperm can survive for 20-30h. Therefore, the suitable mating time is 2-3 hours after ovulation, that is, 20-30 hours after estrus. In recent years, the research tends to be early mating, that is, the first mating is carried out 24 hours after estrus and the second mating is carried out 18-24 hours after the first mating. If the sow is still willing to breed 18-24 hours after the second mating, it can be mated for the third time.

Sows are not in estrus, and the production conditions are not good, so they may not be able to breed in time.