How to improve the annual productivity of sows

The fecundity of pigs is an important index that affects the overall situation of pig production. Many factors cause the decline of fecundity and cause serious economic losses. In order to achieve the goal of raising pigs with high yield, high quality and high efficiency, it is necessary to improve the annual productivity of sows.

1. Fecundity and pig production

The main purpose of raising breeding pigs is to breed piglets and provide pig sources. The annual productivity of sows refers to the number of weaned piglets provided by a sow within one year. There are many factors restricting the annual productivity of sows, the most important of which are litter size per litter and litter size per year. The annual litter number is restricted by the delivery interval, which includes pregnancy, lactation and pending mating period (from weaning to mating). The pregnancy period is a constant component, the waiting period is a basic constant component, and the lactation period is a variable component. It can be seen that early weaning of piglets is an important measure to shorten the delivery interval and improve the annual productivity of sows. For example, when piglets are weaned at 3 weeks, one reproductive cycle is 143 days (115 days of pregnancy, 21 days of lactation, 7 days of waiting for mating) and 2.55 litters per year, while at 6 weeks of weaning, one reproductive cycle is 164 days and 2.17 litters per year.

The number of weaned piglets produced by sows per year is directly related to the cost of raising pigs. The more weaned piglets are produced in the whole year, the larger the fixed cost sharing area is, and the lower the cost is. Improving the fecundity of sows is a systematic project, ignoring any aspect can not achieve the desired goal.

2. Factors affecting the fecundity of sows

The reproductive process of pigs begins with the production of normal germ cells, including estrus, mating, fertilization, blastocyst implantation, pregnancy, delivery, lactation, weaning and so on.

2.1. The main manifestations of reproductive disorders in sows

(1) anestrus: pathological deficiency (abnormal deficiency) caused by diseases of the ovary and uterus.

(2) fertilization disorder: the death of the egg before the sperm enters; the abnormal structure or function of the sperm and egg; the gamete can not function normally to the fertilization site, etc.

(3) prenatal death: early embryonic death. Spontaneous abortion. Mummification. Fetus at birth: death, etc.

2.2. Causes of reproductive disorders

2.2.1, congenital factors, infantile and malformed reproductive organs of sows, cryptorchidism or testicular hypoplasia of boars, etc.

2.2.2, sow dysfunction, endocrine factors, ovarian dysfunction (ovarian dysfunction, atrophy or sclerosis, persistent corpus luteum, ovarian cyst) and so on.

2.2.3, boar dysfunction: lack of libido, difficulty in mating, poor semen quality, etc.

2.2.4, immune factors of sows and antigenicity of boar sperm.

2.2.5. The volume of uterus and the dependence of embryo survival on placenta are increasing. Placental development is affected by intrauterine space and vascular supply. Increasing the number of implantation will reduce the vascular supply of each attachment site and limit embryonic development. The space in the uterus is small, resulting in an increase in the number of embryo and fetal deaths.

2.2.6, chromosome aberration and other genetic factors, variation of chromosome structure and number, gene mutation, inbreeding, intrauterine environment, etc.

2.2.7, reproductive organ diseases, endometritis, uterine hydrops, uterine empyema, scrotal hydrops, scrotitis, dermatitis and so on.

2.2.8, infectious diseases, all diseases affect the reproduction of pigs, serious infectious diseases are parvovirus, classical swine fever, pseudorabies, Japanese encephalitis, reproductive and respiratory syndrome and so on.

2.2.9, nutritional factors, lack of micronutrients, high energy level and so on.

2.2.10, improper management, insufficient exercise, lax mating and disinfection, inappropriate mating, mechanical abortion, feeding toxic, spoiled, frozen, moldy feed, etc.

2.2.11, environmental factors, environmental temperature is too low or too high, captive density is too high, poor ventilation and hygiene, strong noise and so on.

3. Ways to improve annual productivity

It is an important task to improve the annual productivity of sows. Comprehensive measures should be taken to tap the reproductive potential of breeding pigs.

3.1. Attach importance to the genetic basis and strictly select breeding pigs.

As the saying goes, "the boar is good, the slope is good" and "the mother is strong and the young are fat", which shows that breeding pigs have a certain impact on their offspring. Breeding is a very complicated task, and all breeding farms have a set of scientific breeding methods. As a productive pig farm, you should at least look at the mother and choose the best, refer to the previous performance of the sows and choose the best from the large litter, consider the weaning weight and litter weight, and pay attention to the body shape and appearance, from the larger weight, long body, high limbs, sturdy, open, and more nipples. Selected from the offspring of sows with no genetic disease in the whole litter. The sows with long body length have large abdominal space, and the placenta and fetus can be fully extended, which can reduce embryonic death and increase litter size and birth weight. According to the data of Shanghai Yuejin Farm, the average birth weight of sows is below 110cm, the average birth weight of piglets is 1.09kg, and the birth weight of sows with a body length of 120-140cm increases by 17.4%.

3.2. Strengthen the cultivation of reserve pigs and grasp the first mating time.

The reserve pig is the basis for the renewal of the breeding herd, and the growth and development of the reserve pig has a certain impact on the production performance. Although the reserve pig has many of the same characteristics as the growing and finishing pig, the same nutrition supply, feeding methods and management measures can not be adopted. The nutrition level in the diet should be different in the growth stages of pigs in the future. Pay attention to the ratio of energy to protein, fully meet the supply of minerals, vitamins and essential amino acids, and adopt the feeding method of "open front and rear limit". Generally speaking, the body weight 80kg is open before feeding, and it is expected that the body weight will reach 80kg at the age of 5-6 months. After that, limited feeding will be carried out, and the body condition required for breeding must be achieved before breeding, and should not be thin. Let alone be too fat. It is necessary to strengthen management, raise in groups, measure body weight and body size at the age of 6 months, managers should often come into contact with pigs, achieve human-pig affinity, do a good job of enclosure disinfection, cleaning and pig health care and immunity. The breeding and utilization of reserve pigs should be determined by breed, feeding and management level, climate and so on. The sexual maturity of local breeds in China is early, while that of cultivated and introduced varieties is relatively late. generally speaking, sows of local breeds are about 8 months old and weigh about 75 kilograms, while sows of cultivated breeds and introduced breeds are about 10 months old. the body weight is about 120 kg. The body weight and age of reserve boars at the beginning of breeding should be higher than that of sows of the same breed. Early or too late breeding of reserve pigs will have adverse consequences.

3.3. Strengthen the feeding and management of boars to provide quantity and quality sperm.