Dee S A, Joo H S
Department of Clinical and Population Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108.
Vet Rec. 1994 Jul 2;135(1):6-9. doi: 10.1136/vr.135.1.6.
An attempt was made to prevent the spread of the virus of porcine reproductive and respiratory syndrome (PRRS) on three Minnesota pig farms that had been experiencing chronic nursing pig problems, including poor growth rates and increased mortality of post weaning pigs. The PRRS virus and different bacterial pathogens were isolated from all three farms during the initial investigation, and all the farms had a high prevalence of PRRS virus-seronegative breeding animals. All the pigs tested within one week after weaning when they were 18 to 22 days old, were seronegative, whereas 80 to 100 per cent of the pigs tested at eight to nine weeks had antibody titres ranging from 1:64 to 1:1024 by an indirect fluorescent antibody method. The seroprevalence among the finishing pigs on the three farms ranged from 25 to 50 per cent. An eradication protocol was established on each farm, involving emptying the nurseries, followed by pumping out the slurry pits and cleaning, washing and disinfecting three times in 14 days. After the nurseries were repopulated there were improvements in nursery mortality and average daily weight gain, and no seropositive animals were detected in the nurseries on any of the farms; the seronegative status was maintained for the six-month testing period.
在明尼苏达州的三个长期存在哺乳仔猪问题（包括生长速度缓慢和断奶后仔猪死亡率增加）的养猪场，人们尝试阻止猪繁殖与呼吸综合征（PRRS）病毒的传播。在初步调查期间，从所有三个农场分离出了PRRS病毒和不同的细菌病原体，并且所有农场PRRS病毒血清阴性的繁殖动物患病率都很高。所有仔猪在断奶后一周内（18至22日龄）进行检测时血清均为阴性，而通过间接荧光抗体法在八至九周龄时检测的仔猪中，80%至100%的抗体效价范围为1:64至1:1024。三个农场育肥猪的血清阳性率在25%至50%之间。每个农场都制定了根除方案，包括清空保育舍，随后抽出粪坑并进行清理、清洗和在14天内消毒三次。保育舍重新补栏后，保育舍死亡率和平均日增重有所改善，并且在任何一个农场的保育舍中均未检测到血清阳性动物；在为期六个月的检测期内保持了血清阴性状态。
