Monitoring And Analysis Of Antibody Level To Different Immune Procedures Of PRRS In Pigs

Porcine reproductive and respiratory syndrome (PRRS) is an acute infectiousdisease of pig infected by porcine reproductive and respiratory syndrome virus(PRRSV). The disease was reported in1987for the first time, and it has beenspreading all over the country now. It has beening a serious disease that threats thedevelopment of swine industry in our country. At present, the commercialization ofinactivated vaccine and attenuated vaccines were used for preventing and controllingthe occurrence of PRRS. However, there are many reasons. For example, PRRSVowns etiologic characteristics and its special immune mechanism, and PRRS vaccinehas insufficiency in its self, as well as the chaotic implementation of vaccine immuneprogram, which brought a great difficulty in preventing and controlling the disease. Itnot only has no ideal effect after PRRS vaccine, but also has a counter-productive.the study aimed at understanding the real condition after beening vaccinated withdifferent types of PRRS vaccine and immunized by different programs, theimmunization state of different PRRS immunization programs were monitored andanalyzed in LuoYang pig. Based on this, we will put forward a more scientific andeffective PRRS immunization programs to provide a valuable advice for preventingthe disease of PRRS in this region from theoretical and practical aspects.This experimental contents and results were as follows:1. Comparative Study of the difference between the maternal antibodies ofpiglets produced by different sows that immuned by different PRRS vaccine At50d before prenatal period, sows were immunized with PRRS virus vaccine,live (CH-lR Strain) made by Harbin Weike Biotechnology Development Co.,Ltd (HVS)、PRRSvirus vaccine,live made by Boehringer Ingelheim Animal Health Co.,Ltd (BLG) andhighly pathogenic PRRS inactivated vaccine(NVDC-JXA1Strain) made by LuoyangPu-Like Biological Engineering Inc (PLK1). Blood were obtained from all piglets at 7d、14d、21d and35d for detecting PRRS-antibody. Result, the maternal antibody inpiglet is the highest at7d, it can produce a continuing protection on piglet until35d.And antibody positive rate was aboved80%. Immune effects of attenuated vaccines-HVS and BLG were better than the highly pathogenic inactivated vaccine-PLK1.2. Comparative study of the difference between the immune effects ofdifferent pigs that immuned by different day-old Piglets were immunized firstlywith PRRS attenuated vaccine (CH-lR Strain) made by Luoyang Pu-Like BiologicalEngineering Inc (PLK2) at7d、14d、21d、and35d after birth，then blood sampleswere collected at10d、20d、30d、40d、50d for detecting PRRS-antibody,respectively. The results showed that, at50d after first immunization at35d after birth,antibody positive rate in piglets could still reached87.5%, immune effect wasobviously better than first immunization at7d、14d、21d after birth.3. Comparative study of the difference between the immune effects ofdifferent pigs vaccinated by35days of age that immuned by different PRRS vaccineAt35d after birth, piglets were immunized with five different vaccines PLK2、HVS、BLG、Lankeqing-PRRS attenuated vaccine (R98Strain) made by JiangsuNannong Hi-tech co.,Ltd、PRRS inactivated vaccine made by Shandong HistonBiological Engineering Co.,Ltd (SHH). Blood samples were collected at10d、20d、30d、40d、50d for detecting the PRRS-antibody respectively. The results showedthat, immune effect of the imported attenuated vaccine of BLG is the best; however,immune effects of three domestic vaccines--HVS、LKQ、PLK2--just have a slightdifference with each other. In totally, their immune effects were not as good asimported attenuated vaccine; And the worst immune effective vaccine was inactivatedvaccine of SHH.Based on above considerations, the best immunization program to PRRS weredetermined as follows:(1) Vaccine were inoculated with attenuated vaccine-HVS at50d before prenatal period.(2) Piglets were immunized with attenuated vaccines-HVS firstly at35d after birth.(3) The pigs were immunized with attenuated vaccines-HVS secondly at30d after first immunization. Blood samples from the pig wereobtained at the certain period for detecting antibody. The results showed that all pigswere successfully immuned.