Liang Zhang: Large-scale pig farm site assessment
introduction
Recently, Zhang Liang, general manager of Guangdong Mai Microbial Technology Co., Ltd., gave a lecture on "Large-scale Pig Farm Site Evaluation" at the Animal Husbandry Elite Training Network Institute, explaining in detail the concept and elements of pig farm site evaluation. Here are the main ones.
Pig site assessment concepts and elements
The eight elements of biosecurity are: site, pig sales, vehicles, personnel, materials, other animals, feed/water, air, among which the site is the most important and irreplaceable element of biosecurity in large-scale pig farms.
(Figure 1: Site assessment data)
Figure 1 shows that there is a correlation between the incidence of ASF and the site score. In the past two years, through the site evaluation of pig farms, it was found that the incidence rate of 9 farms with a score of more than 700 was relatively low, only 11%, but the incidence rate of 8 farms with a score of less than 500 was about 88%, showing a trend of higher incidence with a lower score.
1. The concept of site assessment
Site assessment, also known as the biosecurity assessment of pig farm sites, is an extremely important biosecurity management tool for large-scale pig farms to identify the main and secondary risk factors in a certain area around the site through spatial epidemiology based on the epidemic law of infectious diseases, geographic information and statistics, and provide important information and decision support for pig farm decision-makers and management to scientifically select sites and control risks.
(Fig.2 The red asterisk is an important reference index and important elements)
Guangzhou Maiwei site evaluation system is an evaluation system established by Maiwei company through years of experience and systematic summary. At present, there are not many pig farm site evaluation systems on the market, the more representative is the PIC breeding pig company's system, the company's site evaluation and relocation scoring system provides a lot of basis for the scientific site selection of many pig farms in China, and Maiwei company has also established its own site evaluation system, our site evaluation system combines the characteristics of domestic diseases, breeding environment, population, terrain and climate, etc., to determine the number of local pigs, density, population and other pollution sources and other 13 indicators and weights, and conduct a comprehensive assessment of the site. The total score is 1,000 points, and there are different minimum points required for different types of farms.
2. Elements of site assessment
There are 13 important indicators including the number of local pigs, the density of local pigs, the type of local pig farms, the number of local pig farms, population and public facilities, other pollution sources, the area and topography, climate and wind direction, water security, transportation, the size of the assessed farm and other animals.
1. The total number of local pigs
The total number of local pigs needs to determine the total number of pigs in the range of 0-2km, 2-5km and 5-10km, and the suspected pig farms should be identified through satellite images during the assessment, and then the number of nearby pigs should be determined with field visits and investigations.
2. Local pig density
Local pig density is defined as the number of pigs per square kilometre within a 5 km radius of the assessed farm (a circle area of 78.5 sq km within a 5 km radius). See Figure 3.
(Fig.3 Evaluation index of pig density within 5km)
3. Density of surrounding pigs
The density of pigs in the surrounding area refers to the density of pigs within the range of 20-50km in the area of action, which can be calculated by obtaining the number of pigs in the area through the relevant administrative departments of the region. The location of the pig farm may involve cross-administrative regions, such as cross-administrative regions, it is necessary to consider collecting data related to the two regions, but it is relatively difficult. See Figure 4.
(Fig.4 Evaluation index of pig density in the range of 20-50km)
4. The type of pig farm within 5km
In addition to the number and density of pigs, the type of pig farm needs to be considered, whether it is a pig farm in its own system or a pig farm outside the system, whether it is a sow farm or a fattening farm, whether it is a two-point or integrated farm, and these indicators are all taken into account. See Figure 5.
(Fig.5 Evaluation index of local pig farm type)
5. The number of pig farms within 5km
Some pig farms are more hidden or relatively small, sometimes they may be ignored, and they need to be verified by the site, most of the time they can be called out through satellite images, but satellite images are sometimes not updated in time or some factories are similar to pig farms or some pig farms do not look like pig farms, but in the field research found that there are indeed pig raising behaviors, if there are farmers in the village free-range can be counted as 1 pig farm in each village. See Figure 6.
(Fig.6 Indicators of local pig farm number evaluation)
6. Population and public facilities
The production and operation of pig farming is very closely related to the surrounding area, and the villages and public facilities such as schools and factories near the pig farm will lead to potential risks such as pork consumption, human flow, logistics, and vehicle flow, and the number of surrounding villages, the number of people and other public facilities can be grasped through satellite maps and surveys. See Figure 7.
(Fig.7 Assessment indicators of villages, population, and public facilities within 5 km)
Biosafety audits will show that the number of villages is highly correlated with the occurrence of diseases, so the number of villages should be taken into account when assessing the site.
(Fig. 8 Correlation between non-plague and number of villages)
In terms of the number of villages (population) around the pig farm during the non-plague period, 2 farms with less than 10 villages within 5 km did not have the disease within 2 years, and 5 farms with more than 41 villages under the same management method had a shorter disease interval, with an average incidence period of 8.2 months. When selecting a site for a new farm, in addition to the density of pigs and the number of pig farms, we should also pay attention to the number of villages within 5km of the plot. See Figure 8.
7. Other pollution sources
There are many other possible sources of pollution, including slaughterhouses, pork product processing plants/freezers, harmless treatment plants for sick and dead livestock and poultry, harmless treatment plants for live poultry, live livestock and poultry trading yards, pig transfer stations, pig truck decontamination centers, manure from other pig farms, organic fertilizer plants, farmers' markets, meat stalls, landfills, incineration plants, transfer stations, sewage treatment plants, etc., these high-risk places are no less threatening than pig farms. Because there are many types of buildings and they are relatively hidden, it is not always obvious from the appearance alone, so it is necessary to communicate with the locals and find out the existence of problems through on-site research.
8. The area and terrain
China has a vast and different area, due to different topography and landforms, resulting in different natural barriers and different risks, relatively speaking, the western plateau and the local hilly areas in the south and east are better, but even if the same area has its own characteristics, it needs to be analyzed according to the specific location.
9. Climate and wind direction
Different climate and wind direction are more important factors to consider in site assessment, the climate score of humid and cold areas is relatively low, cold is conducive to the reproduction of the virus, relatively hot places are difficult for the virus to survive, the score is naturally better, and considering the wind direction, some wind directions have a helping effect on the spread of the disease.
10. Water safety
Water security needs to be considered from two aspects, the first point needs to consider the source of drinking water and the source of water for cleaning, and the second point needs to consider the inundation of waterlogging and flooding, because some areas in the south are prone to flooding in summer, floods can cause a large number of pollutants and spread widely, so water security is also an important reference index for site assessment. See Figure 9.
(Fig. 9 Water security assessment indicators)
11. Main highways
The main highway needs to take into account the distance between the road and the plot, and it is necessary to understand the livestock and poultry vehicles, because the livestock and poultry vehicles are the source of pollution or infection, so the condition of the main highway and the impact on the site are assessed through the livestock and poultry vehicles.
(Fig.10 Satellite image of highway conditions)
12. The size of the pig farm to be evaluated
The larger the scale, the higher the risk, in the site assessment, the pig farm site assessment score is closely related to the size to be planned, the same plot, the small scale of breeding is higher than the large scale of the assessment score.
13. Other animals
Cattle, sheep, cats and dogs, poultry, wild boars, birds, rodents and other animals will have the risk of mechanical transmission such as foot-and-mouth disease and non-plague, and the risk of aquatic feed should be considered in aquaculture, which has a greater impact on the biosafety score.
3. Site assessment application
1. Scientific site selection of the new field
First of all, when building a new pig farm, choose to build a plot with a good biosecurity environment through site evaluation, which can better protect the health of the pig herd under the same biosafety management, and the ideal site can greatly reduce the probability of disease infection.
(Fig. 11 Relationship between 61 pig farms without ASF, PRRS and PED and site scores in Fujian Province)
Through the evaluation of the earliest 61 pig farms with complete information in the initial selection of hundreds of pig farms in Fujian, the average score of the pig farms without non-plague is about 660 points, which is a very good ideal score, and the average score of the blue ear double negative field is even higher, about 723 points. According to the report of Professor Yu Daojin of Fujian Agriculture and Forestry University, there are about 40 blue ear double yin fields in Fujian, which is the province with more blue ear double yin fields in China, which is closely related to biosecurity conditions, and the score value of pig farms without PED is relatively high, see Figure 11. Therefore, the location of the new site should be based on the score of the site, and a good plot can reduce the probability of disease infection.
2. According to the health level positioning, match the site of the corresponding level
(Fig. 12 Health levels of different pig herds)
(1) Site selection of breeding pig farms
According to the health level to determine the corresponding grade of the farm, when the construction of the great-grandfather farm, the proposed plot score does not reach 800 points, no matter how good the plot looks can only be used in pain or downgraded. See Figure 13.
(Fig. 13: Site requirements for different types of pig farms)
(2) Identify risks
For pig farms that have been put into production, it is necessary to conduct regular site assessments to grasp the risks or potential hidden dangers that have arisen in a timely manner, and provide important information and decision-making support for health level positioning and upgrade management.
(Fig. 14 Breeding cooperatives near sow farms and newly built garbage transfer stations next to roads in industrial parks and pig farms)
Figure 14 shows that the original pig farm is surrounded by breeding cooperatives, industrial parks, and garbage stations, in which case regular site assessments can be made in a timely manner, such as correcting the route of road vehicles, and reducing the number of pigs in the pig farms that already have cooperatives next to them.
(3) Risk avoidance and control
(Fig. 15 Different disease resistance at the same site)
Figure 15 shows that the site scores of the two pig farms are almost the same, but the red farm has multiple cases and the green farm has no disease, the reason is that the green farm has achieved different production results and disease prevention and control effects in the same environment through systematic site assessment and regular biosafety audits, identifying risk types, risk factors and risk levels, and carrying out targeted adaptive transformation, while strengthening the biosecurity awareness and skills of employees.
It is worth noting that there are common problems found in the process of site assessment and biosafety audit, we have investigated 50 pig farms that have been put into production, in the past 3 years, 70% have not carried out regular systematic site biosecurity circle assessment, because of weak awareness or lack of personnel or technical force, so it is recommended to conduct professional site assessment on a regular basis, and site assessment has higher requirements for professionalism and experience, and pig farms can be solved with the help of professional third-party forces. See Figure 16.
(Fig. 16 Site assessment of large-scale farms in the past three years)
Fourth, the risk of site assessment practice cases
Case 1: No assessment, no discernment
Some of the changes in the biosecurity environment around the pig farm are silent, some are drastic changes under the eyelids, but without assessment and attention, they may turn a blind eye and lead to inevitable risks.
(Fig. 17 Slaughterhouses near pig farms)
Figure 17 shows that the density of pigs in the surrounding area is very low, and they have been in healthy production for many years, and they were not alerted to the newly built slaughterhouse 1.8KM in the northeast, and did not take disinfection measures such as detouring and strengthening vehicles, materials, and pigs, and became ill after 6 months of production in the slaughterhouse.
The second case: Timely improvement after evaluation
(Figure 18 Detour to avoid risks)
Figure 18 shows that a food company on the side of the road was found on the way to the pig audit in the evening, and it was learned that the factory produced pork products and was recruited by returning migrant workers, and the production workers were mostly nearby villagers. After discovering this risk, the site was assessed in a timely manner, and after the assessment, the vehicle route was changed to drive on the red dotted highway to bypass the food factory, and in addition, in terms of recruiting production workers, in principle, the material interaction was reduced without the use of nearby villagers, and although the score was reduced after the change, the production was relatively stable.
The third case: the assessment of the aftermath is man-made
Figure 18 Risk management after assessment
Figure 18 shows that there is a relatively good geographical town next to the new farm, and there are small farmers around, but there are not many, and when the site assessment field investigated the township farmers' vegetable market 2km to the north, it was learned that there are 5 meat stalls in the market, and about 5 pigs are consumed every day. And the market and the pig farm office, access roads and dormitories are related, there is a risk of cross-infection, because the address location is good and the score is also good, the project can be carried out, after identifying the risk in a timely manner by the project pig farm and the government communication, led by the government and the slaughter farm, meat vendors for tripartite coordination, unified by the pig farm to provide high-quality and low-cost healthy pigs, after slaughter fixed-point supply of the market to avoid risks.
—
Source: "Guangdong Animal Epidemic Prevention Frontline"
Finishing: Liang Lili
Editor: Wang Shihong
Reviewer: Wang Jianlin
Note: This article is for informational purposes only and does not constitute any investment advice.