The first priority in the management of infectious diseases in pigs

The emergence of new pig diseases forces us to re-evaluate the existing production system. If there is no vaccine, improved management methods must be adopted to control the disease; even if there is a vaccine, it may not work without management. This paper provides some basic methods to help pig farms adopt appropriate methods to control infectious diseases according to their respective conditions.

The goal of disease control

It must be clear that the goal is to "control" the disease, not to eradicate it. In general, the control measures are usually to reduce the number of pigs in a reasonable way, cut off the route of infection and properly disinfect the equipment.

To achieve partial elimination by interrupting litter birth, it creates a "bubble" that can swim in the system, and the virus in the field can be completely eradicated only in a small group.

The spread of disease

Is through direct contact between pigs, nasal secretions, saliva, feces, urine; long-term breeding cage carrying disease; vertical transmission through the placenta during pregnancy, born piglets carrying disease The flow of pathogens carrying pigs in the field or introduced from the outside, such as mechanical transmission (vehicles, equipment, shoes, clothes), carriers (insects, rats, mice, birds), air transmission, wild animals, semen insemination from infected boars, etc.

Principles of disease control

No matter which control method is used, strict biosafety procedures must be in place to prevent the entry of diseases, such as transportation (pigs, feed, straw mats), visitors' antivirus clothing, sources of feed and straw mats, water supply, food for carriers, handling of dead animals, etc. The principles of disease control include the following:

Adequate isolation facilities must be established: pig farms must be built away from residential areas, trunk roads, etc.; there is enough space to raise alternative breeding pigs on the basis of full entry and exit; managers are not allowed to work in production areas; breeding livestock must be purchased in highly healthy units and isolated from infected pigs for at least 63 days.

The most important method of control is to stop or at least limit the spread of the disease in the field. If successful control is to be achieved, the management standard of the farm must be improved. Here are four "golden principles": limiting contact between pigs; "stress" is a killer; good hygiene; and good nutrition.

Limit the connection between pigs: disease can be spread through contact between pigs, and limiting contact can reduce the prevalence of the disease. Contact between pigs may be indirect. Injections, surgical tools, instruments and equipment, feces, personnel, carriers (flies, rats, mice, birds).

Stress is a killer: stressed animals can easily get sick; exposure to microbes can put significant pressure on the immune system, and if the immune system is overloaded, bacteria and viruses can cause diseases; if a measure brings stress to pigs, consider whether other methods that produce less stress can be used to achieve the same goal.

Good sanitation: there is no substitute for good hygiene and biosafety measures; cleaning and disinfection of buildings will have an effect; and needles and other tools will not spread disease.

Adequate nutrition: good nutrition, which is not only necessary for growth, but also plays an important role in the development of the immune system; colostrum provides protection against the existing diseases of piglets in this field; ensure that piglets eat as much colostrum as possible within 12 hours after birth; provide high-quality food, especially high levels of antioxidants in the feed of weaned piglets, can help strengthen the immune system.

Management methods that must be adopted

Full-in-all-out system: the source of infection can spread among pigs; full-in and full-out system to prevent this risk; can be applied to all stages of each cycle, such as litter, weaning, growth and fattening, etc.; there can be no crossing between batches of the whole system; pigs that do not meet the standards cannot be mixed into the next batch; staff must follow the animals.

Batch production: due to the limitations of the barn, the traditional weekly production mode is often difficult to achieve the batch isolation required by the full-in and full-out system, instead of giving birth in batches so that each batch can be large enough; the system of batches every 3 weeks has been proved to be effective: the larger the number of each batch, the easier it is to achieve batch isolation; it is in line with the natural law of sows that 3 weeks is a period of estrus and is easy to manage. In the 21-week production cycle, piglets are weaned at 4 weeks after delivery, which is ideal. Facilitate the fine division of weekly labor, such as service, litter birth, weaning, cleaning and disinfection.

Maximize mixed breeding of pigs: mixed farming increases contact between pigs and makes them tense; if possible, keep pig groups unchanged from weaning to fattening; piglets are weaned on the same day and each litter is kept in a small group; if pigs from different litters must be mixed into larger groups, litter size should be minimized; keep growing pigs / grown pigs in the same small circle all the time It is best to achieve the desired group size by dividing each group into small groups, rather than by mixing pigs; pigs in the same group should enter the fattening period at the same time, and the group can be subdivided to adapt to the barn; do not mix groups to increase the size of the group; put an end to mixed farming between different batches in each part of the system.

Strictly implement cleaning and disinfection procedures: most sources of infection live in organic waste; if the pigsty is not completely disinfected, the disease will be passed on to the next group of pigs; pigs should be cleaned and disinfected immediately after moving out; soaked in water to make it easy to remove organic matter; after washing, rinse and rinse with detergent to make it completely dry before moving into the next batch of pigs; place a foot disinfection pool at each entrance.

Manage colostrum when giving birth: it is best for piglets to have good colostrum intake within 6 hours of birth. Some sows may not have antibodies, so consider the "foster care" technique, which is to exchange piglets within 6 to 12 hours (newborn piglets must be fed at least once from their birth mother).

Stop foster care after 24 hours of birth: antibody absorption stops after 24 hours; foster care after 24 hours may contribute to the spread of the virus and should be avoided as much as possible.

Physical isolation between enclosures: open isolation is prone to indirect pigs; prone to the spread of pathogens; the open isolation between enclosures into physical isolation.

When weaning, keep the density of pigs low: the lower the density, the less stress; small stress is equivalent to good health. Recommended density: from weaning to 22 kg 0.3 square meters per head; growing to 50 kg 0.6 square meters per head; fattening 0.75 square meters per head.

Increase feeding points: if piglets fight for food, it will increase stress. Increase feeding sites to reduce competition for food, each weaned piglet has at least 7 centimeters of space, even larger pigs should have enough room to eat, so that they can eat food at the same time.

Good nutrition: usually during weaning, food intake decreases and stress increases; the improvement of the immune system requires a good supply of nutrients; high-quality feed is provided after weaning to reduce stress caused by weaning; feed is updated frequently to keep it fresh; clean water can be easily drunk at any time. If you don't drink this kind of water, why ask a pig to drink it?

Improve the control ability of temperature and ventilation: cold causes stress and reduces immunity; reduce the temperature change of pig living environment; maintain the optimal temperature of pig life; ensure the appropriate temperature of newly weaned piglets. Improved ventilation in the barn helps reduce the recommended maximum level of harmful gas irritation to the respiratory system: ammonia 10ppm, carbon dioxide 0.15%. Eliminate cold and irritating airflow; reduce dust.

Limit the number of pigs in each group: the fewer pigs in a pen, the less chance of disease transmission between individuals; it is recommended that each litter be a group; if you have to mix pigs from different litters to form a larger group, remember principle 3.

Don't cut your teeth when weaning: is it necessary to cut your teeth? It may only play a role in spreading disease.

Strictly implement sanitary measures: ensure good hygiene standards during injection and the end of the section, change needles between different nests, use a lot of tools for disinfection utensils between different pigs, keep them in turn in disinfection trays, keep them independent among cottages; disinfect the pool with the soles of feet; each house uses its own equipment.

Make rules on sick pigs: the longer sick pigs stay in the pen, the more likely other pigs will be infected; formulate a policy on diseased pigs for a long time; quickly move to the fence for treatment. How long will it take to recover and when will he be executed.

Disposal of dead pigs: do not put it around the barn; keep it away from the barn before it is disposed of.

In short, in order to prevent new infections from entering the group, there should be strict biosafety procedures. The better the health of a herd introduced from a highly healthy unit, the less the impact of new diseases in the herd. If we want to successfully control the disease, we must implement a high-standard management system and keep four principles in mind to reduce contact between pigs. Stress is important to kill good health and good nutrition.