1. Introduction
The high incidence of and difficulty in controlling major animal diseases has led to a focus on animal health and its relationship with biosecurity [
1]. The Food and Agriculture Organization (FAO) considers biosecurity to be directly related to agricultural sustainability, food safety, and environmental protection [
2]. The application of biosecurity is the most important measure for avoiding the spread of disease [
3]. Disease prevention through biosecurity measures is considered an important factor in improving animal production [
4]. In August 2018, China experienced an outbreak of African swine fever (ASF), which spread expeditiously across several provinces, resulting in a steep decline in hog production and dramatic market fluctuations [
5]. The outbreak significantly impacted the hog industry, mainly in terms of markets and hog farming entities. The infection led to abnormal fluctuations in the prices of meat, especially pork, disrupting market development and resulting in considerable disparities in regional pork prices [
6]. Most farm owners lacked the experience and expertise to prevent and control the virus. Therefore, the measures taken were inadequate, culminating in low-level biosecurity in farming environments. Consequently, the epidemic brought huge economic losses to hog-farming entities [
7]. Differences in production size, biosecurity standards, production inputs, and sales practices between hog farms can affect the potential risk of disease transmission and lead to a wide variation in the ability to take preventive measures between farms [
8,
9]. The current biosecurity situation in China is not promising; the state of some farms is alarming in the wake of the African swine fever, limiting their productivity, and causing heavy economic losses. Therefore, it is necessary to understand the current situation of biosecurity in Chinese hog farms and investigate the factors that influence the prevention and control of epidemics, to improve the level of biosecurity.
Existing studies on the epidemic prevention behaviours of farmers have mainly focused on specific aspects. The epidemic prevention behaviour of farmers is the first step in animal epidemic prevention and control. Farmers usually perform four kinds of epidemic prevention behaviours, which include, the improvement of feeding conditions, the use of vaccines and veterinary drugs, the reporting of animal epidemics, and the treatment of sick and dead livestock [
10]. Strengthening biosecurity management measures is the most important means to prevent and control African swine fever in China’s pig farms. The construction of a biosecurity system requires attention to the safety of inputs, optimisation of the feeding environment, management of personnel and vehicles, disinfection, and waste disposal [
11]. Zhou et al. [
12] examined the disease prevention and control behaviours of farmers and found that small-scale hog farms focused mainly on disinfection, feed and water management, disease prevention and control, and incoming and outgoing vehicle management. Meanwhile, retail farmers emphasised the regulation of the internal and external environment of hog farms, personnel management, and the use of vaccines and drugs. In a study on biocontainment measures in avian influenza prevention and control, Huang et al. [
13] focused on preventing rodents and birds, as well as measures to manage incoming vehicles and disinfection of personnel. It has also been suggested that four factors: vaccines, veterinary drugs, disinfection and cleaning, and quarantine, play a crucial role in the prevention and control of hog diseases [
14]. The immunisation file, also known as the animal household register, is also an important link in the animal epidemic prevention chain. It records in detail the ages of the animals, entry bar, immunisation date, immunisation identification number, vaccine type, injection, etc [
15]. The establishment of immunisation files by farmers is vital to ensure the implementation of compulsory immunisation programs, and the conducting of risk assessments for the epidemic control of animal diseases to accurately grasp the immunisation status and monitor animals, both overall and individually, to avoid missed and late immunisations and to ensure the overall quality of the immunisation [
16]. Moreover, ensuring drinking water quality is an important component of livestock rearing and management [
17]. Water quality can be evaluated by testing the farm’s drinking water source to check whether the bacterial count exceeds the limit [
18]. Since all types of vehicles are in direct contact with the outside world, vehicle biosecurity and management are also important aspects of hog farm biosecurity controls [
19].
Scholars have long examined the factors influencing disease prevention and control in farms. He Zhongwei et al. [
20] studied the influencing factors of prevention and control behaviours in poultry farmers, taking the individual characteristics, breeding characteristics, epidemic awareness, external environment cognition, and policy implementation as explanatory variables, with which to study the impact of whether farmers adopt epidemic prevention behaviour. Li Yanling et al. [
21] analysed the factors affecting epidemic prevention behaviours from four aspects: farmer characteristics, production and operation characteristics, cognitive characteristics, and environmental characteristics. Studying the relationship between epidemic prevention behaviours and the characteristics of poultry farmers, Li Jie et al. [
10] used further four prevention behaviours: regular disinfection, whether to believe the official warning, whether to clean the chicken cage, and whether to adhere to the “all-in and all-out” system. Song et al. [
22] conducted an empirical analysis of hog farms in the Hubei province and concluded that factors such as farmer literacy, whether they had participated in the training, their knowledge of epidemics, the scale of farming, and whether they had joined a cooperative organisation significantly influenced whether the farmers adopted the disease prevention and control measures. Through a study in the Xinjiang Autonomous Region, Chen et al. [
23]. analysed disease prevention and the control behaviours of cattle and sheep breeding cooperatives and found that the education level of the breeders, whether they had received training, their annual income, and the provision of timely assistance were the main influencing factors. Luo et al. [
24]. studied the disease prevention and control behaviours in beef cattle and meat sheep farms in the Qinghai province and determined that the education level, whether they had received disease prevention and control training, if the farm maintained records of disease prevention and control, and previous certifications were the main influencing factors determining the adoption of the disease prevention and control behaviours by the farmers. Through literature reviews, it can be summarised that there are four main categories of factors that influence the disease prevention and control behaviours of farmers: the characteristics of the farmer, including their gender, age, and education level; the production and operation characteristics, such as the proportion of the farming income in the total household income; the cognitive characteristics of the farmer, such as their cognitive level, the willingness for disease prevention and control and safety awareness; and environmental characteristics, including socio-economic environment and government policies, and what social services are provided [
21,
25,
26].
While many scholars have adequately researched the disease prevention and control behaviours of farmers alongside any influencing factors, there remain some shortcomings. Most of this relevant research merely focuses on a specific region or province and the representativeness of the samples and the universality of the pattern are, thus, inadequate. For this reason, we used the logistic model to empirically analyse the main factors affecting the relevant animal disease prevention and control behaviours, from the perspective of the farmers. Moreover, we analysed the microscopic research data on hog farmers in Sichuan, Hubei, Jiangsu, Tianjin, Liaoning, Jilin and Hebei, and proposed more targeted countermeasures to improve the prevention and control capacity of the farmers, by providing policy recommendations to improve China’s animal disease prevention and control at the grassroots level.
3. Results
In this study, Stata software was used to regress a binary logistic model for each of the three factors influencing hog epidemic prevention behaviours. Prior to model regression, variance inflation factor tests were conducted separately to verify the existence of multicollinearity problems. The results showed that the highest value of the inflation factor of the variables did not exceed 2, implying that there was no multicollinearity problem.
The estimation results show that the three models fit well and the LR statistical significance levels are all highly significant at the 1% significance level. As shown in
Table 6, in terms of individual characteristics, the gender of the farmer has a significant effect, a 10% significance level, on the adoption of disease prevention and control behaviours, whereas having a dedicated means of transport in place, and its coefficient is significantly negative, indicating that male hog farmers are more inclined to adopt dedicated means of transport. This is related to the fact that male farmers, as the main breadwinners of the family, pay greater attention to taking precautionary measures to ensure that household assets are protected from epidemics. At the 1% level of significance, the number of years of education has a positive effect on the adoption of disease prevention and control behaviours by hog farmers. The higher the educational level, the more active a farmer is in adopting the behaviour of testing the water source. This indicates that people with higher educational levels have greater knowledge and access to information about epidemics and take biological prevention and control at the farm more seriously. Technical training had a positive effect on the building of immunisation records and the disease prevention and control behaviours of dedicated means of transport, at significance levels of 10% and 1%, respectively. This indicates that the farmers’ participation in technical training helped to augment their knowledge of disease prevention and control, improved their relevant awareness, and promoted the relevant behaviours required to prevent epidemics.
With respect to farming characteristics, the number of years of farming has a significantly negative effect on the adoption of disease prevention and control behaviours, with a 1% significance level. This indicates that the more years of farming they possess, the less of a priority the farmers attached to disease prevention and control. When they have adequate farming years, they tend to accumulate extensive farming experience, which, nevertheless, will prompt them to rely on their experience in animal disease prevention and control; thus, they are found to lack in science, which results in gaps in their disease prevention and control behaviours. The size of the farm had a significantly positive effect on the adoption of immunisation records and water testing behaviours at the 5% and 1% levels. This indicates that as the scale of farming increases, farmers pay additional attention to the adoption of disease prevention and control measures to avoid huge economic losses from the onset of diseases. At the 5% significance level, the degree of specialisation contributes positively to both the building of immunisation records and the adoption of dedicated means of transport, suggesting that the higher the proportion of total household income from farming, the greater the focus on the biosecurity situations in the farms, with more human, material, and financial resources invested in farming, which is conducive to the adoption of biosecurity prevention and control behaviours.
With respect to disease prevention and control awareness, the farmers’ appetite for risk had a significant negative effect on building immunisation records and water testing at the 10% and 1% levels, respectively. This suggests that the more risk-averse the farmers were, the more active they were in adopting disease prevention and control behaviours. Conversely, the more risk-seeking the behaviour, the more passive they were in adopting disease prevention and control behaviours. This can be attributed to both types of farmers adopting different attitudes towards risks: active and passive. At the 10% significance level, the more the farmers believed that the farm can effectively intercept the introduction of African swine fever, the more likely they were to adopt active disease prevention and control behaviours and test water sources. In contrast, farmers were more likely to build immunisation records when reporting suspected outbreaks at their farms. At the 1% significant level, farmers were more inclined to have their water sources tested and their means of transport dedicated to the farm when reporting suspected outbreaks found in neighbouring hog farms. These data show that the farmers’ active awareness of disease prevention and control can also generate active disease prevention behaviours and exhibit a positive effect.
4. Discussion
Biological vectors and trade are the main methods for African swine fever transmission. Biological vectors generally refer to organisms that infect and carry the African swine fever virus (ASFV). For example, ticks, wild suids, and domestic pigs. Susceptible pigs have direct or indirect contact with these infection sources, which then transmit the African swine fever. In trade, infected pork products, swill, alongside equipment and vehicles are the media of ASFV [
27,
28]. Epidemiological studies revealed three main routes of ASFV transmission: 46% was spread by unsterilised vehicles and workers, 34% by swill-feeding pigs, and 19% by trans-regional transportation of pigs and products [
29]. Unsterilised vehicles and people are the main vectors in the spread of African swine fever, and strict control of vehicles and people entering farms is particularly necessary. The questionnaire survey revealed that most farms have strict control over people and vehicles, whereby foreign vehicles and people are not allowed to enter at will, and farms have special transport as well as vehicle decontamination areas, although this does not cover all farms, and a small number of farms are still loosely managed. In terms of feed and water, only 2.63% of farmers feed their pigs with slop, which is excellent. However, for drinking water, more than half of the farmers have not tested their water sources, which greatly increases the risk of contamination in the farms and poses a threat to the health of the hogs.
Regarding the prevention and control measures of ASF, there is no commercialised vaccine at present, and the focus on prevention and control of ASF is “prevention”. The only control measures are to find infected pigs as soon as possible, to either cull or treat them harmlessly, or block and isolate them [
30]. Chai Weihua et al. [
31] discussed the measures to strengthen pig breeding management and disease prevention and control based on the three elements of infectious disease control: controlling the source of infection, cutting off the transmission routes, and protecting susceptible populations. Starting with “prevention”, represents cutting off all the paths through which the virus may spread. It is strictly forbidden for people outside the pig farm to enter, and the staff should be disinfected and protected when entering and leaving. Disinfect the materials and vehicles entering the pig farm, and when introducing breeding pigs from outside, it is necessary to set up an isolation and observation period before they become gregarious and attempt to adopt a population management mode of “all-in and all-out” to improve the biosecurity barrier. An Dong et al. [
32] concluded that ASF should be prevented and controlled by isolation measures, standardised disinfection procedures for farms, training of farmers on biosecurity knowledge, and international border epidemic prevention. The biosecurity measures taken on the surveyed farms focus on cutting off the means of transmission. Biological control is carried out to prevent birds, rodents, and insects from entering the farm, and to disinfect and control the people and vehicles. In terms of pig management, 90.08% of the farms are zoned, with sows, feeders, and piglets kept separately. However, only 33.59% of the farms adopt “all-in, all-out” management practices for their pigs, which undoubtedly increases the risk for the farms not currently adopting such management practices, as those newly introduced pigs may carry viruses into the farm, increasing the risk of infection for pigs throughout the farm.
In terms of the farmers’ characteristics, men are more aware of epidemic prevention and actively take epidemic prevention actions [
33]. As the head of the family, men bear the main business responsibilities, thus, taking active epidemic prevention actions to avoid economic losses. The more educated the farmers are, the more inclined they are to take epidemic prevention measures [
34]. The higher the educational background, the more knowledge you will receive, and the higher your ability to acquire information and learn new knowledge. When an epidemic occurs, you will take active defensive measures. Farmers with more years of farming possess rich farming experience, yet this also means that they will follow the old rules. Compared with farmers with fewer farming years, they pay attention to different disease prevention and control measures [
35]. The larger the size of the farm when faced with an epidemic, the greater the losses suffered will be, having the intrinsic motivation to adopt epidemic prevention and control behaviours as well as the financial ability to support them [
22].
The relationship between risk perception and the adoption of conservation behaviours by farmers has been examined by scholars. The results of Valeeva’s study revealed the direct importance of the intrinsic risk characteristics of farmers for their adoption of risk management strategies [
36]. Self-protective (risk-averse) behaviours, in general, directly contribute to the farmers’ decisions to exhibit more specific farm-protective behaviours. This is the exact opposite of the derived empirical results. Conversely, the results of the study indicated that farmers with a higher perception of animal disease risk tend to adopt bird-proofing measures, and those who prefer risk tend to disinfect their vehicles. This is consistent with the results of this paper. The reason for these different results is the different meanings of the measurement indicators. In the questionnaire, “high risk, high return”, “medium risk, medium return” and “low risk, low return” were used as options to measure the farmers’ risk preferences. The empirical results show that farmers with a ‘high risk, high return’ bias are more likely to adopt epidemic prevention behaviours. The outbreak of ASF in China led directly to a shortage of pig stocks and a sharp rise in pork prices [
37]. On the one hand, restocking brings huge economic benefits to farmers, but at the same time, they are exposed to the risk of further contracting the ASFV. These farmers, who prefer “high risk, high reward”, are driven to replenish their farms by the huge economic gains, but at the same time take active measures to protect themselves against the risk of the ASFV.