1. Positive and unstable state: porcine PRRS antigen and antibody double positive. If the sow farm is at this stage, it means that more sows have viremia and detoxification. In the late stages of pregnancy, there are abortions and reproductive disorders, and even piglets in the farrowing room have diarrhea or respiratory symptoms in nurseries and fattening houses. If managed effectively, this phase will not last more than 1 month.
Stop loss first: reduce the viral load in the environment + ** drug delivery (combined with the results of drug susceptibility tests). Reducing the viral load in the environment is mainly achieved through the thorough and effective disinfection of empty pens and the effective disinfection of pigs in the disease stage (whichever is the lesser of two evils) and reducing the feeding density. In the cold season, it is necessary to strengthen the effective insulation of nursery piglets after weaning. Generally, PRRS-positive and unstable pig farms, in addition to respiratory symptoms, will also be accompanied by unsatisfactory fat conditions during the nursery stage (even the proportion of pigs with vertebrae exposed is relatively high), so the energy level in the nursery material should be increased to increase the ability to resist stress. In addition, the disinfectants commonly used in pig farms are chemically treated, but it is best to verify them experimentally to see if they are effective against the virus. The factors that affect effective disinfection are: water quality, temperature, light, organic biofilm, effective concentration, disinfection equipment, water droplet particle size, spray volume per unit area, contact time with pathogens, etc. Management measures such as batch management + all-in, all-out + thorough cleaning and disinfection of empty bars are the basic management methods for effective control and purification of diseases.
Immediate anti-stress + physical enhancement measures + continuous reduction of viral load in the environment play an important role in relieving the metabolism of fat in the process of stress and fat loss. Reducing pathogen load in the environment is a long-term and continuous behavioral process.
Caution in the use of vaccines + elimination of strongly positive sows + measures to improve quality and increase immunity + continuous reduction of viral load in the environment. As a general rule, we should try not to use vaccines as much as possible.
Nutrition is the foundation for building a good immunity. Many pig farms do not pay enough attention. For example, from the time the gilts are incubated to the farrowing bed, there are many people on the farms that feed the pregnant sows or even the control of the feed, and sooner or later there will be problems. Because in addition to fetal development, the first-born sow itself has gained more than 100 pounds from breeding to delivery, and the feed-to-meat ratio of this weight gain is much higher than that of commercial pigs, and in the whole field feed, pregnant sow feed is the lowest energy feed, plus the control of feed will also lead to insufficient intake of vitamins and amino acids, which will lead to chain reactions, such as coat color and obvious hooves problems. Is it feasible to feed firstborn sows with lactating sow feed in some farms?This is not recommended because the energy of the nursing feed is too high, which can easily lead to obesity in first-born sows, and even chain problems such as dystocia or high postpartum elimination rate or second-born syndrome. From 60 kg to farrowing beds, it is recommended to feed the gilts all the time, or to feed the sows with a suckling sow premix according to the large formula of gilt feed.
For PRRS positive unstable farms, after taking the above management measures, the symptoms of each link will be significantly improved within about 1 month, and then, combined with the elimination of strong positive sows + quality improvement and exemption measures + continuous reduction of the viral load in the environment, it can gradually improve. Unless there is a low-level wrong management practice, causing the PRRS virus to spread. Here are several examples of common mismanagement operations: frequent transfer of pigs in the farrowing room (which will accelerate the horizontal spread of PRRS virus among the piglets in the farrowing room), disorderly transfer and random merging of piglets in the upper and lower farrowing rooms and weaned pigs (the merging of pigs of different gestational ages will also increase the horizontal spread of PRRS, and it is recommended that PRRS positive farms implement parity management), ineffective disinfection, chaotic management of old, weak, sick and disabled pigs (the assessment plan is mainly based on survival rate assessment), Disturbances in the immune program (eg, mycoplasma immunization behind live PRRS vaccine) may even occur.
2. Positive stable state: PRRS antigens in the pig herd have yin and yang (more yang and less yin), and positive antibodies. Stabilization at this stage is only clinically invisible, such as miscarriage or a large number of reproductive disorders, or a reduction in the clinical symptoms of the nursery. It does not mean that there is no viremia and no detoxification, but it is relatively rare.
At this stage, the pig herd can choose pulse drug administration + effective disinfection (continue to reduce the viral load of the environment) + improve quality and increase immunity + anti-stress measures + all-in and all-out + small cell management + thorough cleaning and disinfection of empty pens + batch management + management according to parity + reduce the frequency of pig boarding + suckling piglets "three levels of protection and suckling pig wound management" + good environmental control + nutritional allocation at all stages (nursery to improve feed energy) + correct domestication operation of reserve breeding pigs and so on.
3. Provisional negative status. PRRS antigen negative and antibody positive in the pig herd. The management method is the same as in the previous stage, but it should be added that the change in the positive rate of antigen and antibody detection of PRRS in the pig herd is tracked. The test is generally done once a quarter, and the recommended method of sow sampling: large group of sows: 30 heads of light fetus, heavy fetus, and empty pregnancy (10 sows can be collected at each stage of small groups);Commercial pigs: 10 at birth and 10 at 25 weeks of age. It can also be evenly distributed across buildings by gestational age and randomly sampled.
If the management of the 2nd and 3rd states is done well, it can be completed in one breeding cycle and the transition to the 4th state. The medium management level requires 2 breeding cycles, and the management is almost almost complete, and the transformation to the 4th state can be completed within a maximum of 3 breeding cycles.
4. Negative status: PRRS antigen and antibody double negative. It is easy to introduce double yin breeding pigs, but it is difficult to maintain double yin. The benefits of PRRS are significant, and the requirements for the management team and management details are very high if you want to maintain PRRS double-negative. How long this stage can be maintained depends on the error rate of the operator (management methods and management details are the same as above).