The pork zircovirus of the second type (RSV-2) is one of the visual examples of a multifactorial disease of pigs. And today there is no doubt that the presence of zircovirus type 2 (PCV-2) leads to the occurrence of a disease, moreover, this virus is ubiquitous, and it is difficult to find a farm that is completely free from this infection. Therefore, the outbreak of the disease or simply a subclinical infection does not depend, in fact, on the viral agent (only partially, in accordance with the PCV-2 genotype, which is infected with the animal), and rather depends primarily on the starting mechanisms and a number of factors that have a negative effect.
As from an epidemiological and experimental point of view, it was demonstrated that PCV-2 coinfection with a reproductive-reservation virus of pigs (PRRSV), pork parvovirus (PPV) and Mycoplasma Hyopneumoniae can lead to serious losses associated with RSV-2 on a farm. That is why it was recommended to control the zircovirus by monitoring parallel diseases in the absence of a vaccine against PCV-2.
Control of co -infections does not necessarily lead to the disappearance of zircovirus, but also reduces its negative effect. Undoubtedly, PRRSV is regarded as an important pathogenic microorganism in the development of zirco-viral infection, and when we encounter RSV-2, the question automatically arises: is there PRRSV? Now the reverse question should be posed: whether RSVAD (diseases associated with zirco -virus) on farms are always present in the RRSS is always present?
Pig genetics is a key factor in the susceptibility and / or resistance of pigs to the RS. Despite the fact that this factor was not considered seriously in 2002, there was a large number of evidence that some genetic lines or a specific genus were susceptible to the disease. Today this is a recognized fact, but the mechanisms of resistance and susceptibility are not yet known.
Of course, there are much more risk factors and trigger mechanisms, however, the scientific and technical community has agreed on the three main groups of trigger mechanisms: management methods, related diseases, genetics.
This is obvious when you are faced with the situation of the RSV-2 on a certain farm, and you need to eliminate or try to eliminate the main trigger factor. How this specific risk factor can be defined? What is the impact of its elimination? How easy it is to eliminate it? (When it comes to PRRSV, “evidence” does not mean that it can be easily eliminated, and at the same time it is impossible to be sure that this is the main risk factor.)
The emergence of new effective vaccine products and successful PCV-2 control forced to partially forget about zircovirosis as a multifactorial disease.
Practical experience
Today it is recognized that zircovirus of type 2 pigs is widespread everywhere, and zirco -viral infection has a significant impact on economic indicators in pig farming. Various vaccination programs have been developed to combat the disease. The purpose of this experience is to compare the effectiveness and economic feasibility of vaccination of piglets with a new 1 ml vaccine (No. 2) against PCV -2 with a previously used 0.5 ml vaccine (No. 1). Experience was conducted in the province of Brittan (France). The number of farming was 700 sowing, the growing cycle — from exposure to the end of fattening. The farm worked in a weekly production rhythm, the erects of the piglets were carried out at the age of 21. The herd was positive in the PCV-2, the swine reproductive-reservation virus (PRRSV), actinobacillous pleuropneumonia (ARR), Mycoplasma Hyopneumoniae and Lawsonia Intracelllaris. The immunization of sows of the 2 ml anti -cyclated vaccine began in mid -2006, and shortly before this experience began to vaccinate piglets with the same vaccine of 0.5 ml (1198 heads). He was hedes in arbitrary order by two groups, an ear tag was attached to each piglet. The first group of piglets (599 heads) intramuscularly introduced vaccine No. 1 (0.5 ml), the second — vaccine No. 2 (1 ml). Both groups were held in separate sectors, but in one room. The household staff did not know what vaccines the groups immunized. To determine the course of zirco -viral infection in each group, 9 times took 9 blood samples and tested it with PCR (3 samples from each): when leaning, on the increase, in the middle and at the end of fattening. Each piglet was weighed when excommunicated (at the age of about 21 days), then after 140 days — until the first piglets are the first piglets. Pigs, the final weight of which was 25% lower than the average weight, was pushed out of experience. Data on each individual carcass was recorded on the face. Average daily growths were calculated for the period from leaving to the face. In each group, they took into account, antibiotics of each individual pig was carried out by antibiotics. Based on the production indicators of individual piglets and data on the case calculated economic benefits as gross profit for each piglet. Gross profit is equal to profit from each pig minus dead piglets and feed costs (reference price: 1.05 euros / kg pork, 21 euros / piglet, 195 euro / t feed).
Statistically, the weight during excommunication, the final weight, the average daily assignment from the withdrawal to fattening was evaluated on the basis of the criterion of the Steiden; Treatment of individual piglets, culling and death was evaluated based on the chi-quadratite criterion.
Results
The presence of PCV-2 during experience confirms the positive result of the PCR in the middle and at the end of fattening. The difference in death levels between vaccinated piglets was obvious. The difference in the level of death during the period from withdrawal to fattening was more than 60% (3.3 versus 8.7%).
Production indicators of pigs, which were vaccinated by vaccine No. 2 (1 ml), were much better than in a group vaccinated by vaccine No. 1 (0.5 ml). In addition, pigs vaccinated by vaccine No. 2 (1 ml) were clinically healthier, which is indicated by a much smaller number of piglets that needed antibiotic treatment (3.6 versus 6.3%).
Conclusions
In the herd of sowing with a zirco-viral infection caused by PCV-2, in a group immunized vaccine No. 2 (1 ml) compared with the group, where vaccine No. 1 (0.5 ml) was used, death indicators and culling were lower, the score indicators are higher and also needed a fewer antibiotics. These results show the effectiveness of a new 1 ml vaccine against the negative effect of infection caused by PCV-2. The increase in profit was 7.8 euros for each pig.