Feeding and management techniques of pregnant sows

The process from mating conception to delivery is called pregnancy, which is the longest stage in the reproduction and production of pregnant sows. the basic task of raising and managing pregnant sows is to ensure fertilization, the full growth and development of embryos and fetuses in the mother, and to prevent the occurrence of fetal transformation, abortion and stillbirth, so that pregnant sows produce a large number of piglets per litter, birth weight, strong physique and uniform and neat piglets. Reasonable supply of full-price nutritious feed, reduce the effects of stress, ensure that sows have moderate body condition during pregnancy, lay a good foundation for lactation, and ensure normal growth and development of sows.

Metabolic characteristics and body weight changes of pregnant sows

The growth and development of fetus, uterus and other organs increase the appetite of sows and increase the digestibility and utilization rate of feed, so we should try to meet this requirement in feeding, but pregnant sows should not gain as much weight as possible, but should control to a certain extent the weight gain of lean sows by 35-45kg and 32-40kg.

The growth and development of embryos and fetuses during pregnancy

The growth and development of embryos is characterized by the formation of organs in the early stage, the increase of body weight in the later stage, the formation of organs in about 21 days, the increase of more than 60% of fetal weight after 90 days of pregnancy, and the increase of protein, fat and water content of embryos. In particular, the mineral content increases rapidly, and the growth and development of the embryo goes through three key periods from the beginning of the fertilized egg to the fetal maturity.

1. In the first critical period, in the first 30 days, the fertilized egg moved from the fertilized site to different parts of the uterine horn and gradually formed the placenta. Before the placenta was formed, the placenta was easily affected by environmental conditions. Imperfect feed nutrition, feed mildew, all kinds of mechanical stimulation, high fever and so on will affect the growth and development of embryos or cause early embryo death. During this period, embryo development and sow weight gain are slow, and there is no need to increase the number of diets.

2. In the second critical period of 60-70 days, the fetus develops rapidly and squeezes out each other, which can easily lead to uneven nutrition supply of the fetus located in the middle of the uterine horn. Causing fetal death or dysplasia, rough treatment of sows, shouting, whipping, chasing, and crowded bites among sows will affect uterine blood circulation. Increase fetal mortality.

3. In the third critical period, after 90 days, the fetal growth and development increased rapidly, the metabolic assimilation ability of sows was strong, the body weight increased rapidly, the required nutrients increased significantly, the fetal volume increased, the uterus expanded, and the digestive organs were squeezed. Digestive function is affected. Reduce the amount of green feed. Increase concentrate, especially cake feed with more protein, to meet the needs of rapid growth of sow weight and fetal growth and development.

Feeding of pregnant sows

1. Nutritional requirements of pregnant sows

With the increase of the number of days of pregnancy, the need for nutrients in pregnant sows increased, especially in more than 20 days before delivery, in which protein, calcium and phosphorus were the most needed. Therefore, in the feeding of pregnant sows, the gestation period of sows is generally divided into two stages, the first 80-90 days is called pre-pregnancy, and the last 20-30 days is called late pregnancy, so as to give different feeding, not only to ensure maternal health, but also to ensure that the fetus is fully developed.

(1) nutritional needs in the first trimester. The embryo in the first trimester develops slowly and does not need much nutrition. Too much concentrate feed can lead to early embryo death. Therefore, the feeding standard of empty pregnant sows is generally adopted.

(2) nutritional needs in the later stage of pregnancy. The growth rate of the fetus is accelerated in the later period of pregnancy, especially in the last 30 days, and the maternal nutrition reserve is difficult to meet the needs of the fetus, so it is necessary to improve the feed nutrition level, which is beneficial to the development of the fetus and the quality of childbearing. It is of great benefit to increase the reserve of nutrients in the mother and the need for postpartum lactation. In the later period of pregnancy, the volume of the maternal uterus and its contents increases, which increases the pressure on the abdominal cavity. In order to avoid the compression of the uterus due to feeding, and at the same time to increase the nutritional food intake, the proportion of concentrate should be increased, the feed volume should be reduced, or eating more meals should be reduced to prevent sows from overeating, indigestion or constipation. Each head was fed 2.5-2.8kg of the mixture with above nutrition level daily.

2. Feeding methods of pregnant sows.

In the process of feeding, due to the age of the sow. Development, physical condition is different, there are many different ways of feeding. However, no matter what kind of feeding method is adopted, fat feeding must be taken. Pregnant sows should be moderately fat, and postpartum sows should reach 70% to 80% fat before delivery. 80% of the first-born sows should be fat. The feeding amount was determined according to the fat condition and physiological characteristics of sows.

The main results are as follows: (1) the feeding method of grasping two heads in the middle is suitable for sows with poor body condition after weaning and sows with long lactation period. In rural areas, this method is chosen because of the low level of feed nutrition, good lactation performance of local breeds of sows and poor physical condition of sows. Form a "high-low-high" nutritional level throughout pregnancy.

(2) the step-by-step feeding method is suitable for first-time sows. Sows are still growing and developing at the time of breeding, and the nutritional requirements are large, so the nutritional level of the whole pregnancy should be gradually increased, reaching a peak in one month before delivery. The ways are to increase the nutrient concentration of feed and increase the amount of feed, mainly to increase protein and minerals.

(3) the method of pre-coarsening and finishing, that is, the method of pre-low and post-high, this method is suitable for parturient sows with better fat condition before mating, usually early weaning sows with better nutrition level.

(4) in the "consistent" feeding method, the synthetic metabolic ability and nutrition utilization rate were enhanced during pregnancy, and the whole feed supply "consistent" feeding method was adopted while keeping the comprehensive nutrition of the feed. It is worth noting that in the feed preparation, to prepare a good feed nutrition, but high, can not be too low.

3. the main problems in the breeding of pregnant sows.

The feed quality of pregnant sows must be guaranteed. Any moldy, frozen, toxic and strongly irritating feed (such as distiller's grains and cottonseed cake) can not be used to feed pregnant sows, otherwise it is easy to cause miscarriage; the feeding time and frequency should be regular, that is, it is appropriate to feed 2-3 times a day; the feed should not be changed frequently and suddenly, otherwise it is easy to cause digestive maladjustment. The diet must be comprehensive, diversified and palatable, and the supply of green roughage should be limited after 3 months of pregnancy, otherwise it is easy to oppress the fetus to cause abortion.

Management of pregnant sows

The central task of pregnancy management is to protect the fetus, create a favorable environment, promote the normal development of the fetus, and prevent mechanical abortion, especially in the second trimester of pregnancy. The management of breeders should be strengthened.

1. Raising in single column: the width is 60-70cm and the length is 2.1m; to ensure that each pig eats evenly and does not collide with each other, this method is adopted in general large-scale pig farms.

2. Environmental hygiene: keep the pig house clean and hygienic, do a good job of timely cleaning and regular disinfection of pig house feces and urine, ensure that the ground is dry, reduce the humidity in the circle as much as possible, and provide a quiet and comfortable living environment to reduce all kinds of noise as much as possible. Do a good job in preventing cold and heat.

3. Proper exercise: for pregnant sows, proper exercise is beneficial to enhance physique, promote blood circulation, accelerate fetal development, and avoid dystocia. It should be noted that prenatal exercise should be stopped for a week to prevent sows from giving birth on the playground; in the first month of pregnancy, in order to restore physical strength and health, exercise should be reduced.

4. Ensure feed hygiene: do not feed moldy or poisonous feed. It is worth noting that the pig food trough is not cleaned regularly, not disinfected, the leftovers are not cleared, the feed in the trough is the most moldy, and the new material will also be contaminated, which is very harmful to the health of pigs for a long time, and it is easy to cause miscarriage.

5. Patient and meticulous management: strengthen inspection to observe whether the sow's appetite, drinking water, defecation, urination and mental state are normal.

6. Do a good job of immunization.

Treatment of common problems in pregnant sows

1. Pregnancy estrus (false estrus): pregnancy estrus means that sows still have slight estrus within 1-2 days before and after the next scheduled estrus. This kind of false estrus is different from true estrus, which is that the appearance of estrus is not obvious, and only the vulva is slightly swollen; sows are slightly uneasy, but their appetite is not decreased, and their response to boars is not obvious, so they generally refuse to mate. The reason may be the imbalance of reproductive hormone secretion, that is, insufficient progesterone secreted by corpus luteum on ovary and excessive estrogen secreted by placenta. Or the nutritional status of sows in the first trimester is very poor.

[preventive measures] improve the nutritional status of sows before mating and in the first trimester of pregnancy, prevent and treat diseases of reproductive organs of sows in time, and do a good job of preventing cold and keeping warm.

2. False pregnancy: the pig is not pregnant after mating, but the abdominal circumference increases day by day, the breast also develops and expands, to the "parturient period".

Before and after, sometimes the breast can also squeeze out milk, but finally do not give birth, abdominal circumference and breast slowly shrink back, this phenomenon is false pregnancy. Phase occurs because the embryo dies early and is absorbed, but the corpus luteum of pregnancy continues to exist and plays a role in secreting progesterone. This phenomenon is caused by endocrine disorders caused by malnutrition, changeable climate and diseases of reproductive organs.

[preventive measures] improve the nutritional conditions of sows before and after pregnancy, prevent and treat diseases of reproductive organs of sows, add some green and succulent feed before and after mating, or add appropriate amount of vitamins to ingredients to ensure normal follicular development and ovulation.

3. Metamorphosis, stillbirth and abortion of sows: the embryo is absorbed by the uterus after death in the early stage of pregnancy, which is called metamorphic fetus (invisible abortion). Occurs in the middle and later stages of pregnancy, the fetus dies, but is not excreted, and the water in its tissue is absorbed by the mother and turns brown, just like a mummy, which is called a mummy; if the fetus dies soon after giving birth with the live baby and the fetus does not change, it is called stillbirth. Abortion refers to the disorder of the physiological process of the fetus or mother, or the destruction of the normal relationship between them, resulting in the interruption of pregnancy.

The causes of metamorphosis, stillbirth and abortion are quite complicated, which can be summed up in several aspects:

The main results are as follows: (1) the time of mating is not appropriate, and the sperm and eggs have aged. Although the fertilized eggs can be fertilized, the vitality of the fertilized eggs is low, which is easy to cause early death and be absorbed by the mother to form a transformed fetus.

(2) inbreeding leads to an increase in the number of stillbirths, as well as freaks and malformations.

(3) Dietary nutrition of pregnant sows is not comprehensive, especially lack of high quality protein, minerals (calcium, phosphorus), vitamins AEB and so on cause embryo death.

(4) feeding pregnant sows with moldy, deteriorated, toxic or strongly irritating feed, or frozen feed, resulting in poisoning and abortion.

(5) sows are overfed or have long-term constipation, which can easily cause stillbirth.

(6) the pigs in the second trimester of pregnancy are too full, and the gastrointestinal contents oppress the fetus, which can also cause premature delivery, dystocia or stillbirth.

(7) improper management of pregnant sows, such as whipping, scaring, chasing too quickly, making sows cross ditches, slide to, bite each other or crowd each other in and out of narrow pigsty doors, etc.

(8) in the hot summer, the heat prevention and cooling of the pig house was not done well, the temperature in the house exceeded 32 ℃, and the number of embryo death increased.

(9) the reserve sows were mated too early, the fetus was too large and the pelvis was narrow, which caused the piglets to asphyxiate and die during delivery.

(10) improper clinical use of drugs, such as laxatives, insect repellents, dexamethasone, oxytocin, etc.

(11) poor hygiene and poor disinfection in pig houses lead to infection of the birth canal of sows and death of embryos due to the disease. these diseases mainly include classical swine fever, parvovirus, Japanese encephalitis, pseudorabies, leptospirosis, toxoplasmosis, brucellosis, mold pig blue ear disease, high fever.

[preventive measures] strict management was carried out according to the feeding and management measures of sows in each stage, and the causes of the above diseases were overcome in each stage of feeding and management. Pregnant sows with abnormal diet or non-eating behavior, redness and swelling of the vulva and outflow of mucus, from time to time, the sows that may have an abortion should be injected with corpus luteum through 10-30mg in time and take sedatives to protect the fetus. For sows that have swollen breasts and secrete milk when they reach the due date, abortion is inevitable or stillbirths have been mummified and remain in the womb, induced abortion can be taken. The method was to inject 4mg of estradiol 6-8h followed by intramuscular injection of oxytocin 3-6mg or dexamethasone 200mg.