Department of Pathology and Infectious Disease, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire AL9 7TA, UK.
Vet Rec. 2013 Apr 27;172(17):449. doi: 10.1136/vr.101195. Epub 2013 Mar 8.
Bovine Viral Diarrhoea Virus (BVDV) is a pestivirus in the flaviviridae family which affects cattle worldwide. Bulk milk (BM) antibody testing is frequently used as a relatively quick method of assessing herd BVDV exposure; however, an understanding of the effects of vaccination and historic infection is essential for test interpretation. This study investigated the trends exhibited by monthly BM antibody analysis in 14 herds split into three categories. Category 1 herds (vaccinating/no persistently infected (PI) animals) began the study with mid-positive BM antibody titres and experienced an estimated increase of 0.007 optical density (OD) units per month (equating to a rise of 0.35 OD units in 50 months). Category 2 herds (not vaccinating/no PI animals) began the study with mid-positive BM antibody titres and experienced an estimated decrease of 0.005 OD units per month with antibody levels in one category 2 herd taking 1290 days to decrease from mid-positive to negative. Category 3 herds (vaccinating/PI animals present) began the study with high BM antibody titres which plateaued within this range throughout the 50-month observation period. Vaccination was observed to cause transient increases in BM antibody in a number of herds in categories 1 and 3.
牛病毒性腹泻病毒（BVDV）是黄病毒科的一种瘟病毒，影响全球的牛群。批量牛奶（BM）抗体检测常被用作评估畜群 BVDV 暴露的相对快速方法；然而，了解疫苗接种和历史感染的影响对于测试解释至关重要。本研究调查了分为三类的 14 个牛群中每月 BM 抗体分析显示的趋势。第 1 类牛群（接种/无持续感染（PI）动物）开始研究时具有中等阳性 BM 抗体滴度，估计每月增加 0.007 光密度（OD）单位（相当于 50 个月内增加 0.35 OD 单位）。第 2 类牛群（未接种/无 PI 动物）开始研究时具有中等阳性 BM 抗体滴度，估计每月减少 0.005 OD 单位，其中一个第 2 类牛群的抗体水平需要 1290 天从中等阳性降至阴性。第 3 类牛群（接种/存在 PI 动物）开始研究时具有高 BM 抗体滴度，在 50 个月的观察期间，该范围的抗体滴度保持稳定。在第 1 类和第 3 类的一些牛群中，观察到疫苗接种会导致 BM 抗体的短暂增加。
