What are the main reasons for the prevalence of swine fever?
On August 14, an outbreak of swine fever was confirmed in Zhengzhou, Henan, which was the second swine fever outbreak in our country in recent times. Although the outbreak has gradually been brought under control, there are still sporadic cases. Swine fever is an acute febrile infectious disease caused by a virus, and its morbidity and mortality rates can reach 100 percent. There are many causes of swine fever, most of which are due to the lack of a correct management approach in daily operations. Below I will introduce the main reasons for the prevalence of swine fever.
1. Lax quarantine of introduced breeding stock
Most large-scale farms now purchase replacement breeding pigs from outside, and according to expert experimental surveys, half of the pigs that develop swine fever are caused by replacement breeding pigs and piglets. Therefore, it can be concluded from the survey results that many farms do not carry out strict introduction quarantine when purchasing replacement breeding pigs. This leads to the introduction of pigs with latent infection, providing susceptible targets for swine fever and bringing in sources of transmission.
2. Frequent circulation of live pigs
With the increasingly rapid pace of economic development and the trend of economic globalization, free trade among people has gradually increased. The circulation of live pigs and pig-derived processed products across the country and even the world is becoming faster and faster, and quarantine is not strict. Many pig dealers privately slaughter and process pig products. In order to seek profits, they use large numbers of dead and diseased pigs, thereby causing the spread and diffusion of swine fever.
3. Low vaccine quality
Although every pig now needs to be vaccinated against the disease, the current vaccine is produced from the C-strain attenuated virus. The dosage used abroad is 400 RID, but the dosage used domestically is only 150 RID. Therefore, due to insufficient dosage, the disease resistance is not strong, and it cannot completely cut off the disease caused by subclinical infection, leading to a vicious cycle and accelerating the transmission and infection of the swine fever virus.
4. Improper immunization procedures
When carrying out vaccine immunization, attention must be paid to the influence of maternal antibodies. When immunizing a pig herd, pigs should receive the first immunization at one month of age and the second immunization at two months. When a sow is pregnant, swine fever vaccine must absolutely not be administered, because it will cause fatal harm to the fetal pigs. Small pig farms in many places generally do not carry out antibody testing and inject vaccines based on their own ideas, so immunization failure often results.
5. Influence of drugs and feed
In addition to swine fever, pigs also have some other diseases, such as gastroenteritis and pneumonia, so some drugs must be used accordingly. However, some drugs have a certain inhibitory effect on lymphocyte proliferation in the animal body, such as streptomycin, neomycin, and others. These drugs will affect the immune effect of the swine fever vaccine. Antibiotics must not be used indiscriminately or in excessive doses. When injecting the vaccine, control the dosage well to prevent affecting the effect.
The above are several main reasons causing the prevalence of swine fever. Of course, there are more than these reasons; there are also effects such as disease and nutrition. If the synthesis of antibodies in the pig body is affected and the pig's own immunity is lowered, swine fever can easily be triggered. Swine fever is fatally harmful to pig herds. As mentioned earlier, the infection rate and mortality rate of swine fever can reach 100 percent. Therefore, everyone must pay attention to the points mentioned by the editor, and I also hope it can be helpful to everyone.