Study Of PRRS Control On Replacement Pigs Of Large-scale Pig Farm

Porcine Reproductive and Respiratory Syndrome(PRRS),commonly known as "blue-ear disease",is a highly contact sexually transmitted diseases caused by Porcine Reproductive and Respiratory Syndrome virus(PRRSV),which will give rise to pregnancy sow abortion or prema ture birth,stillbirth and mummy foetus,decreased the survival rate of piglets,aswine respiratory disease.The disease give serious threat to the healthy development of pig industry and bring huge economic losses to.However in largescale pig farms,prevention and control of PRRS to the backup breeding herd will has a particularly important significance to stableing control of the whole Blue ear pig disease.At present,blue ear disease immune background of the reserve pig breeding herd can be divided into three categories: thefirst kind is introduction of the negative for the original breeding pig farm and its PRRSV antibody of backup breeding herd serum is negative.The second is strong positive for antibodies to swine(S/P values > 2.5).The third is PRRS stable immune swine(antibody S/P value of 0.4 to 2.5).In this study,different immune vaccine and drug intervention programs were designed three types of backup pigs.Wherein the PRRSV antibody negative group,immunization program was composed with two different strains,the first classic PRRS vaccine(ATCC VR-2332 strain),the second mutation strain(JXA1-R strain)three weeks later.The strong positive pigs were treated using C hinese and Western medicine.The treatment process was as follows: Shuanghuanglian 3 g / head / day + aivlosin 1.5 g / head / day,one meal a day,lasting 10 days;Then change medicine,Shuanghuanglian 3 g / head / day + Taiyong 2.5 g / head / day,one meal a day,even with 10 days;And then replace the drugs,gold and blue 3 g / head / day + aivlosin 1.5 g / head / day,one meal a day,even with 10 days;The pigs with stable PRRSV antibody were immunized with classic PRRS vaccine(ATCC VR-2332 strain).After treated,the serum were collected from each group and the antibody levels were measured by ELISA method.Meanwhile,herd test temperature,mental status,eating habits of the treated groups were observed everyday.The results indicated that the levels of antibody increased slowly after the first immnization.The average of S/P value was about 1.41.But after the second vaccine with mutation strain,the S/P value increased to 1.91 quickly.This levels also sustained for 3 weeks.For the strong positive group,the S/P value declined to 0.4-2.5 in 76% of the group and 6% <0.4 after drug treatment for 30 days.For the positive and stable group,the antibodies showed stable longer.During the whole procedure of this study,most pigs were nomal by clinical obersearvation(only 13 pigs took food less.4 pigs showed high tempreture,but recovery quickly after 3 days treatment).This study indicated if the differernt treatment was taken to different back-up pig with different immune status of PRRS,the antibodies would be controlled in the more ideal levels.The program of immunization and drug treatment could act as an reference for other pig farms.