How to improve the reproductive utilization rate of sows in breeding pigs

The reproduction rate of sows is related to the economic benefits of large-scale pig farms, is an important symbol of transforming potential biological productivity of sows into real productivity, and is an important index to measure the comprehensive production level of a large-scale pig farm.

Keep the population structure of sows reasonable

Establishing and maintaining a reasonable sow population is a basic work of large-scale pig farms and a fundamental measure to achieve high quality, high yield and high efficiency. The reasonable group structure of sows is that 1-2 sows account for 30%-35% of the total production of sows, 3-7 sows account for 60%-7 sows account for 5%-10%. In order to realize the balanced production of pig farms, we should plan to select excellent reserve sows and gradually renew the pig herd so as to improve the quality of the pig herd. The reserved sows should conform to the breeds or cross combinations specified in the breeding plan. Individual selection should be strict, require strong limbs, good reproductive performance of female parents, more than 10 offspring, normal development of vulva, no genetic defects, no less than 7 pairs of effective nipples, neatly arranged, no inverted nipples, blind nipples, small nipples and so on. The reserve sows should also be strengthened to make them develop well and have a good reproductive condition.

Take measures to increase litter size

The temperature of pig house has a lot to do with sow breeding. In general, the suitable temperature of reserve sows is 17 ℃ ~ 20 ℃, and that of pregnant sows is 11 ℃ ~ 15 ℃. This is because high temperature can increase the body temperature of sows, high uterine temperature is not conducive to the development of fertilized eggs and embryo implantation, high embryo mortality and low litter size. Cooling measures can be taken to keep the temperature in the house less than 21 ℃.

Timely mating is very important to obtain higher litter size. Early or too late mating will lose some eggs, thus reducing the litter size. When the oestrus sign of the sow is obvious, the boar is allowed to climb or manually test or see the boar not moving, and then repeated once in 12 hours, it will generally achieve better mating effect and higher litter size. Large-scale pig breeding is generally repeated twice, such as once before feeding in the morning, once before feeding in the afternoon, such as breeding in the afternoon, and once again in the morning of the second day.

Mastering the first mating age and timely mating, sows in estrus for the first time or boars climbing over mating for the first time are basically unable to conceive. The first mating age of reserve sows is not less than 8.5 months old, and the body weight should be more than 110 kg. Mating in the second or third estrus is more ideal, early mating will affect the litter size and the second mating, too late mating will affect the conception rate and service life. In order to obtain a higher litter size, it is necessary to master the appropriate mating age to prevent premature and too late.

To shorten the lactation period by early weaning, it is more appropriate for sows to be weaned from 21 to 28 days after birth. At this time, weaning had little effect on the fat condition of sows and the litter size of the next litter, and had less adverse stimulation on piglets. The weaning time of young sows should be postponed to about 35 days old, which is beneficial to maintain or increase the litter size of the second birth.

Do a good job of protecting the fetus to prevent miscarriage. After parturient sows are transferred to groups or light foetus sows are enclosed, they should be carefully observed and carefully managed, such as finding signs of abortion or injecting progesterone into sows with a history of miscarriage.

When sows were injected with ovulation promoting No. 2, there were about 20 ovulations in a period of estrus, and the ovulation lasted for 10 hours to 15 hours. Sows treated with LRH-A2 could promote egg maturation and centralized ovulation, thus increasing the conception rate and litter size.

Increase the nutritional composition of sows

Although the requirement of vitamins and other trace elements is very small, they are necessary nutrients to maintain the health and normal development of sows and play an important role in the breeding process of sows. For example, vitamin A deficiency can lead to sexual cycle disorder, abortion or stillbirth, weak fetus, deformed fetus or blind fetus, and reduce live litter size; vitamin D deficiency can reduce conception rate, litter size and survival rate before weaning; vitamin E deficiency reduces ovarian function and reduces follicular luteal cells, thus reducing litter size and high mortality of piglets before weaning. Iron deficiency will reduce the survival rate of piglets, copper deficiency will make sows give birth to more stillbirths, manganese deficiency will lead to the development of inhibitory organs, abnormal bone development and so on.

Reasonably eliminate sows with low production performance

There is a plan to adjust the breed structure and age structure of sows, to add high-quality reserve pigs in time, and to maintain a reasonable and healthy sow population structure. The general principles of elimination are as follows: sows with habitual miscarriage or uterine inflammation that have not been cured for a long time, sows that have been bred for three consecutive times without fetus or two times of estrus, sows with decreased production performance of more than 7 births, sows without estrus for two months after weaning, sows with poor lactation performance, such as sows that have no milk or bite offspring after delivery, sows with less than 5 litters in a row, sows with postpartum paralysis or sows affected by foot and foot disease.

Control the spread of diseases to pigs

Large-scale pig farms should adopt self-breeding and strictly prevent the introduction of reproductive diseases. The imported breeding pigs from other pig farms should be strictly isolated and observed for more than one month to ensure the health level of the purchased breeding pigs. The reserve sows should be vaccinated with parvovirus disease, pseudorabies and Japanese encephalitis before breeding to prevent the occurrence of reproductive disorders. Sows suffering from vaginitis and uterine inflammation should be treated in time. They can be washed repeatedly with normal saline or 1 ‰ potassium permanganate solution, injected with penicillin and streptomycin, and then mated after uterine purification.