Sew -- the strategic choice of the industrialization development of healthy pig raising

Introduction: Based on the analysis of the current situation of Swine Health threatened by epidemic disease at home and abroad, this paper expounds the new technology system for purifying or controlling swine epidemic disease -- early weaning and isolation feeding technology (segregated early Weaning (sew for short), including the origin and principle of sew, the technical content and key points of sew, the production process of sew, the technical evaluation and economic analysis of sew This paper reports the author's recent research cases Through the implementation of sew, a new negative herd of pigs was successfully constructed from the old farms with positive pathogens (PRRS, pseudorabies and asthmatic diseases) The daily gain before 75 days of age was increased by more than 50% It is pointed out that sew is an economic and effective technical way to purify or control the epidemic diseases in pig farms, and it is also a strategic choice for the industrialization of healthy pig breeding Key words: sew, healthy pig raising, early weaning, isolation feeding, purification of pathogen 1 Pig production is facing severe health challenges Since the development of large-scale pig industry, the application of achievements in lean pig breeding, nutrition and feeding has made the productive potential of pigs better explored At present, the biggest threat to pig industry should be epidemic disease China's pig industry is still difficult to adapt to the requirements of healthy pig breeding in the aspect of disease control technology system The direct economic loss caused by the death of the disease every year is up to 10 billion yuan, and the indirect loss caused by the disease, such as the decline of production performance, the waste of feed and artificial, and the consumption of medicine, is even greater All kinds of explicit and recessive losses caused by the epidemic disease increase the production cost of pig enterprises and often lead to unprofitable or even loss Pig disease is not only a great harm to the safety of livestock products, but also a result of the disease, which leads to the multi drug use (including treatment drugs and drug additives in feed) in the feeding process, resulting in drug residues Pork with pathogenic pollution and drug residues on the market is a threat to human food safety and seriously endangers human health Therefore, no matter from the perspective of pork production or consumption, disease is the first bottleneck restricting the sustainable development of China's pig industry The following is an example of the current situation at home and abroad: 1.1 the emergence of new epidemic diseases: porcine reproductive and respiratory disorders syndrome (PRRS) was first found in North Carolina in 1987, and then spread rapidly in most pig countries in the world in less than 10 years [1] In recent years, it has been widely spread in China In 1996, Canada first reported the weaning pig multiple system failure syndrome (PMWS) In fact, there were clinical diseases of PMWS as early as 1991 [3] Since then, similar cases have been reported all over the world China's PMWS was first reported in 2001 [4] In 2001, it was seriously ill in Guangdong, Zhejiang, Shanghai, Henan and other places In 2002, it was in Beijing, Liaoning, Henan, Fujian, Shan East, Tianjin and other cities are seriously ill Some epidemic diseases, such as Nipah disease, Getah disease and hyperplastic enteritis, have been found in China, and some new swine diseases continue to show signs of introduction to China [5,6] 1.2 atypical of traditional diseases: in the past, classical classical classical swine fever has been relatively rare, and now it mostly occurs in the whole country as atypical (mild) swine fever It can take many forms, such as reproductive disorder of sows, congenital infection of newborn piglets (mass death before weaning), persistent infection, immune tolerance and asymptomatic virus In the past, infectious pleuropneumonia and atrophic rhinitis were mostly recessive infections of pigs In recent years, they have developed into stress diseases In many pig groups, including dozens of pigs, acute group infections are also common In the past, pseudorabies infection was very mild, but in recent years, it has developed into one of the most serious swine infectious diseases endangering the global pig industry 1.3 the immune system is attacked: many pathogens (especially viruses), such as porcine reproductive and respiratory syndrome, pseudorabies, swine influenza and swine circovirus II, attack the immune system of pigs and cause immunosuppression Immunosuppression can make the pathogen with low pathogenicity cause a variety of disease complex, even to the extent that it is difficult to control It can also cause increased response to vaccination, increased side effects, or immune failure and no response to treatment The threat of immunosuppressive diseases to pig health is increasing 1.4 damage to suckling piglets and weaning piglets: suckling piglets often suffer from placenta vertical infection; weaning piglets are prone to infection due to the decrease of maternal antibody level, combined with multiple stresses such as weaning, refueling, population transfer, high-density feeding, etc As the immune function of suckling piglets and weaning piglets is not sound, the mortality rate is high after the onset of the disease, and the survivors are mostly dead pigs, which severely hit the pig industry PRRS, PRDC and PMWS have caused serious losses to suckling and weaning piglets in many farms 1.5 the problem of respiratory syndrome (PRDC) is becoming increasingly prominent: due to the increase of production scale and feeding density, the poor microclimate environment in the pig house, and frequent turnover, the stress response is increased, resulting in the decrease of the resistance of the pig body, which leads to the occurrence of pig respiratory system transmitted diseases more and more frequently Porcine respiratory disease complex (PRDC) is a general term of respiratory diseases caused by the interaction of virus, bacteria, environmental stress and low immunity of pigs At present, PRDC has almost become the number one disease that affects the economic benefits of the global pig industry It occurs in all pig farms in China and is difficult to remove In addition to the direct death caused by PRDC, it is more serious to slow the weight gain (5% - 25%), reduce the feed utilization rate (5% - 25%), delay the time of marketing (15-20 days), and carry a variety of related pathogens for a long time [7] 1.6 severe death in the first outbreak: in recent years, the emerging infectious diseases, in the first outbreak, due to the lack of an effective specific immune barrier in the pig population, tend to be acute, spread rapidly, and die heavily The incidence of stillbirth in PRRS was more than 20%, and the mortality of suckling piglets was 30% - 100% The mortality of PMWS in acute outbreak can be as high as 20-40% 1.7 circular infection with disease production: under the intensive high-density feeding mode of continuous operation of breeding, conservation and fattening, once the disease is introduced, it will be transmitted vertically between the mother and the offspring and vice versa from the "old" fattening pig to the "young" fattening pig, resulting in the repeated circular infection of the disease origin in the pig population, which is difficult to remove, seriously affecting the production performance of the pig 2 The origin and principle of sew 2.1 the origin of sew technology in pig production all over the world are deeply troubled by diseases Human beings have been exploring effective methods to control and purify pig diseases There are two main ways of disease transmission in pig farms: sow vertical transmission to piglets and horizontal transmission between different pig groups Among them, the vertical infection is the root cause of the continuous and difficult to eradicate Piglets are born in a sterile state After birth, due to contact with sows or the surrounding environment, they are infected with bacteria, then horizontal infection among pigs, and even the whole group spread At present, there are mainly two kinds of pig pathogen purification technologies in the world: SPF (specific pathogen free) technology and sew (segregated early weaning) technology SPF technology was founded by George young, Ph.D., Nebraska State University in the 1950s It is a kind of surgical production method [8] At present, SPF pig herds have been established in 13 countries and regions, of which Denmark has the fastest development Sew technology has been widely used in the developed countries of pig raising in North America since 1990s, and now it is spreading rapidly in the world The origin of sew technology can be traced back at least to the 1860s At that time, Dr chuck roe and Dr Tom Alexander, Ontario Veterinary College, University of Guelph, Canada, explored non-surgical methods to achieve the same disease purification effect as SPF pigs In the late 1970s, Dr Tom Alexander, consultant of PIC company and now working at the University of Cambridge, UK, successfully developed medicated early Wening (MEW) technology, with non-surgical method and low cost, has purified a variety of bacterial diseases in a pure pig farm of the company, including chronic respiratory and digestive tract infectious diseases such as MPs, AR, SD, and the effect is similar to that of SPF technology [9] Mew programs include early (5-day-old) removal of piglets from sows and treatment of piglets with high concentrations of antibiotics, as well as extensive vaccination In the late 1980s, Dr hank Harris, an American pic company, improved the mew technology, named modified medicated early weaning (MMEW) The weaning age of piglets was extended to 10-21 days, and the piglets were isolated from the breeding farm after weaning [10] When Dr hank Harris and his colleagues realized that weaning piglets in isolation was the key to the success of MMEW technology, they renamed MMEW isowien Dritz (1994) et al Pointed out that in order to prevent the vertical infection of the mother, all non-surgical ways of weaning such as mew and MMEW are called early weaning (SEW) [11,12] Later, many researchers found that as long as the mother and baby were isolated in time, even without many anti infective drugs, some diseases could be more economically purified, making sew technology more mature and practical The National Pork Producers Council (nppc) of the United States proposed its own sew program, including weaning piglets at the age of 16 days, isolating 100 piglets in each pigsty, artificial insemination of sows and treatment of specific drugs In recent years, the basic framework of sew technology has not changed greatly, but there are some new changes in feeding management, nutrition, pig house design, facilities and equipment, etc 2.2 sew technology principle the theoretical basis of EW Technology is that sows are the most dangerous source of disease transmission Studies have shown that the vast majority of adult sows and reserve sows entering the breeding age are seropositive for many infectious diseases, but sows themselves are safe and immune to many diseases Piglets can rely on the passive immune resistance pathogen obtained from colostrum maternal antibody before 2-3 weeks of age, and can rely on the active immune resistance pathogen generated by themselves after 5 weeks of age, but in the weak period of immunity between 2-5 weeks of age, if they coexist with sows in this period, they are vulnerable to infection and move for life The key technology of sew is to realize super early weaning of piglets and keep them away from sows to cut off the vertical infection of pathogens from sows to piglets before the arrival of this immune weak period (about 14 days old, which is related to the disease types that need to be purified) In the later conservation period and the whole process of growth and finishing, different batches of pigs are always in a relatively clean environment and isolated from each other To block horizontal infection among pigs 2.3 compared with SPF, sew and SPF are both modern pig production technologies researched and developed for the purpose of purifying diseases of non transplacental route infection in pigs Compared with SPF technology, sew technology has the following advantages: (1) non-surgical non-invasive production technology, which can be used multiple times by sows to improve the utilization rate of sows; (2) small investment, difficult to implement technology