Technical Measures for High Quality and High Yield of Free-range Sows in Rural A

Xingli WANG

Animal Husbandry Development Promotion Center of Linshu County, Linyi 276700, China

Abstract Today, with the rapid development of modern and large-scale pig industry, free-range pig farming is still an important part of the breeding industry. Different from large-scale pig farms, there are many shortcomings in feeding management, pig disease prevention and control and so on for small-scale farmers. In the long-term clinical diagnosis and production practice, it is found that sows raised by small-scale farmers often have some problems, such as non-estrus, repeated infertility and "false pregnancy", weak farrowing, stillbirth, and postpartum piglet death. This paper makes a comprehensive analysis on the performance and etiology of the above-mentioned free-range sows, and puts forward the corresponding prevention and control measures, in order to provide a theoretical basis for the feeding and management of rural free-range sows.

Key words Free-range sows, High quality, High yield, Etiological analysis, Control measures

1 Morbidity and clinical symptoms

From October to December 2020, through the treatment of sick sows raised by more than 30 small-scale farmers, it was found that sows had the problem of "fake pregnancy" for 2 small-scale farmers; 5 free-range sows had dystocia and gave birth to only one or two very big piglets; there were 6 sows with stillbirth and weak fetus in 6 small-scale farmers; there were sows in 3 small-scale farmers having dystocia for unknown reasons; there were sows in 4 small-scale farmers having estrus but failing to succeed in mating for many times; there were non-estrus sows in 3 small-scale farmers, about 10 d after giving birth to piglets, the sows from 5 small-scale farmers lost weight and died one after another; in 12 small-scale farmers, the sows did not eat for 7 to 10 d before delivery, and the piglets died after delivery and the feed intake of sows gradually returned to normal. In addition, sows in most small-scale farmers had multiple symptoms of the above-mentioned diseases.

2 Clinical examination and etiological analysis

2.1 Disease factors of sows

2.1.1

Reproductive system diseases. Through clinical examination and etiological analysis, some of the sows with the above symptoms have infectious inflammation in the reproductive tract, including hysteritis, vaginitis,

etc.

, resulting in the death of sperm in the reproductive tract; some oviducts are blocked due to tubal inflammation, which hinders the combination of eggs and sperms, resulting in a significant reduction in the number of fertilized eggs. Some die because of endometritis that makes it difficult or impossible for embryo or fertilized eggs to implant. In view of the reproductive tract diseases of sows, farmers often blindly use drugs to treat them, resulting in the residue of some drugs in the reproductive tract and the death of fertilized eggs due to the harmful effects of drugs in the reproductive tract. In addition, due to various reasons, abnormal development of reproductive organs, deformity, persistent corpus luteum, ovarian cyst, ovarian stillness and so on, lead to reproductive dysfunction in sows and lead to infertility. Due to the poor feeding conditions for small-scale farmers, sows and piglets are more likely to be infected with reproductive disorders such as parvovirus disease, blue ear disease, pseudorabies, Japanese encephalitis and circovirus disease.

2.1.2

Hypothermia. Sow hypothermia is a clinical syndrome of pig body temperature drop caused by improper feeding management, management imbalance, insufficient heat production or excessive heat dissipation in sows. Sick pigs show a sudden onset, body temperature of 35-37 ℃, mental depression, obvious loss of appetite or even abstinence, serious cases may be unable to stand and there is generally no other medical history. The sudden change of climate is the inducement. In particular, sows from rural small-scale farmers have more diseases when cold waves come in winter and there are no heat preservation measures in pens and most of diseases occur in sows with poor feeding conditions, weak physique and late pregnancy.

2.1.3

Prenatal fasting. Due to improper prenatal feeding and management of sows and unreasonable feed nutrition, the sows are overfed, which leads to the rapid development of fetuses and the increase of intraabdominal pressure in sows. And the lack of exercise results in gastrointestinal peristalsis and even constipation, causing a decline in food intake or even fast.

2.1.4

Postpartum paralysis. Sows lack nutrition, and especially there is imbalance of calcium and phosphorus ratio or insufficient vitamin D content in feed; poor breeding environment, cold and humid pig house, incomplete disinfection, lack of light and exercise,

etc.

easily lead to obstacles to the absorption of calcium salt in sows. In addition, if postpartum care is not in place, sows are deficient in both qi and blood after delivery, and the ability to protect against cold is weak, especially in cold winter, cold wind attacks will cause animal meridian block and paralysis.

2.2 Parity of sows

It is the best for normal sows to give birth to less than 7 piglets. With the increase of parity, the sows gradually weaken and their physical fitness decreases, which increases the probability of dystocia, weak farrowing, stillbirth and so on.

2.3 Timing of mating

At present, under the common situation of recessive estrus in sows, some small-scale farmers did not determine the best mating time according to the performance and symptoms of estrus and ovulation in sows, and did not arrange mating for sows in estrus in time. In addition, most of the small-scale farmers began to breed before the sows matured, which had a certain impact on the normal growth and development of sows.

2.4 Extensive management

Most of the small-scale farmers lack the necessary breeding facilities and equipment, such as temperature control system, ventilation equipment, disinfection and isolation facilities, and fecal treatment facilities, resulting in poor living environment of sows. A good environment is the basis of raising pigs, but the facilities of pig houses for small-scale farmers are simple. For example, some pig houses are half-shed and half-house structure, which often lead to poor heat preservation effect due to excessive ventilation, excessive temperature difference between day and night. In some pig houses, the proportion of windows is small, and the ventilation effect is poor. High temperature and humidity in summer, and poor ventilation in the house, result in excessive concentration of harmful gases such as NH, CO, HS and pathogenic microorganisms in the house. Some pig houses do not have direct sunlight all the year round, and sows have been in a dark and humid environment for a long time; some pig houses are too narrow, and sows can not get enough exercise.

2.5 Serious pollution to drinking water for sows

The random discharge of industrial wastewater and breeding wastewater and the extensive use of pesticides in crops have seriously polluted the source of groundwater in some rural areas. Small-scale farmers usually directly use groundwater nearby for breeding, resulting in a general decline in the physique and disease resistance of free-range sows in rural areas.

2.6 Feed and nutritional factors

Excessive feed nutrition and excessive feed intake of sows lead to excessive obesity in sows, which in turn leads to excessive fat accumulation in follicles and fallopian tubes of sows. This affects the normal ovulation and estrus of sows, resulting in repeated infertility or dystocia caused by weak uterine contraction during delivery. Insufficient feed nutrition and low feed intake of sows lead to malnutrition in sows; lack of vitamin E and selenium in feed leads to insufficient secretion of reproductive hormones in sows and various diseases such as anestrus in sows. The feed quality is poor, the content of mycotoxins and heavy metals exceeds the standard, and the toxins of sows accumulate in the body after feeding, invading many organs including the reproductive system.

2.7 Drug abuse

Small-scale farmers have poor ability to diagnose whether sows are sick or not. Once misjudged, they will use drugs in excess of dosage and course of treatment, resulting in long-term accumulation of drugs in sows.

2.8 Stress response

Abrupt climate change, vaccination, noise, driving and catching, animal disturbance and other stress factors can induce the disease of sows and piglets.

2.9 Unstable semen quality and non-standard artificial insemination operation

At present, artificial insemination is widely used in small-scale farmers, and most of them purchase boar semen. Most of the small-scale farmers do not have the equipment to detect the quality of sperm, and the semen with a small number of sperms and low motility can not be detected at the first time, so that the sows are still not pregnant after the completion of artificial insemination. In addition, the operation of artificial insemination in small-scale farmers is not standard and proficient, which can easily lead to the phenomenon of infertility or low probability of conception in sows.

2.10 Inbreeding

If the breeding boar is not replaced for many years, it will lead to inbreeding, increase the probability of weak farrowing and abnormal fetus in sows, and even cause breeding failure in sows. If breeding fails many times, it may cause infertility in sows.

3 Prevention and control measures

3.1 Improving the isolation and disinfection measures and optimizing the environmental conditions of the pig house

Small-scale farmers should try their best to improve isolation and disinfection facilities and equipment, avoid mixed breeding of many kinds of animals, especially non-captive animals (cats, dogs,

etc.

), and insist on rodent control. Breeders should reduce their outings and reduce the number of outsiders entering farms. It is necessary to optimize the heat preservation, ventilation and lighting facilities and equipment for the pig house, build a waste treatment device adapted to the breeding capacity, clean up the manure in time, and keep the pig house clean and tidy.

3.2 Strictly controlling feed and raw materials

It is necessary to put an end to feeding moldy and deteriorated feed and raw materials. Feed and raw materials should be stored in places that are dark, well ventilated and dry, and should be used within the shelf life.

3.3 Strictly controlling water sources

It is best for individual farmers with conditions to feed sows with tap water. If they want to use groundwater, they have to use water 30 m below the ground. When necessary, microorganisms, agricultural and veterinary drugs, heavy metals and other harmful substances in groundwater should be detected regularly, and the choice or purification of groundwater should be decided according to the test results.

3.4 Adding microecological preparations of proprietary Chinese medicine to put an end to the abuse of antibiotics

According to the actual situation of sows, Chinese herbal medicine compound additives and microecological agents (plant lactic acid bacteria,

Saccharomyces

cerevisiae

,

Bacillus

subtilis

,

etc.

) should be reasonably added to the feed. Chinese herbal medicine additives can play a good role in the prevention and treatment of reproductive disorders in sows. The illegal use of antibiotics as additives is prohibited, and the indications, course of treatment and dosage of the therapeutic antibiotics allowed to be used should be strictly controlled.

3.5 Environmental control

3.5.1

Summer heat prevention and warm keeping. In the construction of pig houses, the small-scale farmers should adopt thermal insulation building materials, the building space should be moderate, and it is best to make pig houses face south, surrounded by trees for shading. It is necessary to keep warm in winter and cool in summer as far as possible, and keep the interface of cooling and heating equipment, and use heating and cooling equipment when necessary.

3.5.2

Ventilation and daylighting. There should be a natural ventilation window in the sow house, and the vent setting should be reasonable to ensure adequate ventilation in the house. An electric fan should be installed in the ventilation window, and fan ventilation is used if necessary (preferably negative pressure ventilation) to ensure that the ventilation volume of the house is up to standard. The ventilation window adopts a glass window that can be opened and closed, and the closed glass can be installed directly in the daylighting window.

3.5.3

Deodorization. The pig house should be connected with the biogas digester, and the manure is sent to the biogas digester in time. The pig house should be cleaned in time and often disinfected, and the rain and sewage diversion design should be implemented in the breeding site.

3.6 Vaccination

It is necessary to formulate vaccination and immunization procedures in line with the local epidemic situation for the backup sows and parturient sows of small-scale farmers. Backup sows should be immunized with parvovirus disease vaccine twice a year, and parturient sows should be immunized once before mating; porcine Japanese encephalitis vaccine should be used once in March and September respectively each year; vaccination should be carried out against swine fever and pseudorabies 3-4 times a year.

3.7 Regular deworming

During the non-pregnant period of sows, deworming should be carried out in time, and avermectin should be injected subcutaneously twice at an interval of 1 week. For free-range pigs, special attention should be paid to the elimination of

Taenia

solium

, especially for the farmers living with pigs, praziquantel, albendazole, mebendazole and other drugs can be used alternately.

3.8 Sow breed selection and elimination

The piglets with good development and more nipples should be selected as backup sows, and the sows with defects, high parity and poor reproductive performance should be eliminated regularly, and the sows with abnormal reproductive system development, long-term non-estrus and no improvement in estrus after treatment should be eliminated as soon as possible.

3.9 Ensuring semen quality and mastering mating techniques

The small-scale farmers should continue to carry out artificial mating for sows, strictly check the quality, quantity, transportation and storage of sperm needed, and examine the semen quality with a microscope before mating under certain conditions. It is necessary to grasp the timing of mating of sows, do a good job in disinfection preparations before mating, and avoid mating failure and other adverse consequences caused by wrong mating timing and irregular insemination operation.

3.10 Formulating and implementing feeding management procedures of pregnant sows

Appropriate feed should be given according to different stages of sows to ensure adequate and balanced nutrition of sows in different stages of production. When necessary, vitamins and trace elements should be added to the pregnancy feed and lactation feed of sows to ensure the nutritional needs of sows. It is necessary to formulate and strictly implement scientific feeding procedures to prevent sows from being too fat or too thin, and to ensure that sows have sufficient exercise and light.About 20 d after pregnancy is the period of normal placental formation, embryo implantation and early fetal development. At this stage, Ganshenkang and Jinweitai (main ingredients: vitamin B1, vitamin B2, calcium pantothenate, vitamin B6, vitamin C, vitamin E, carotene, folic acid, sodium selenite, oligosaccharides,

etc.

), microecological agents and mildew remover can be added to the feed, and they should not be used continuously for more than 10 d.

In the middle stage of sow pregnancy, fish meal, bean cake, carrot, blood meal and some green feed should be added to ensure the nutrition needed for the normal development of the fetus. At the same time, Fuzheng Jiedu Powder, Baotai Wuyou Powder and Jinweitai should be added to the feed (1 kg added to 1 t of feed for 10-15 d per month) to ensure the health of mother and baby.

The late stage of pregnancy (90 d of pregnancy to 3 d before delivery) is the stage of rapid fetal growth. During this period, short-term fine feeding is needed. Every day, each sow should be fed 1 kg of mixed concentrate or 5%-6% of animal fat or edible oil on the basis of the original feed diet, which has a good effect on the weight and survival rate of newborn piglets. And 1 kg/t microecological agents can also be added to the feed and used continuously to maintain the balance of intestinal flora in sows. The diet should be reduced by 1.5 kg/d for 3 d before delivery, and brown sugar and wheat bran should be given on the first day before delivery to reduce the burden on the intestines.

3.11 Postpartum management

Sows suffer from severe postpartum physical loss and weak gastrointestinal function, so their physical fitness should be supplemented as soon as possible. Sows should be given feed with little gastrointestinal stimulation, easy digestion and absorption and comprehensive nutrition. A small amount of feed should be given on the same day after delivery, and the feed should be gradually increased from the second day, and the sows should be allowed to eat freely after 7 d. During this period, we should strengthen the work of heat preservation, cleaning and disinfection, strengthen nursing and avoid stress factors. At the same time, Chinese herbal medicine can be added to the feed to remove external pathogens, strengthen genuine energy, and ensure the health of sows and piglets.