Crawford R P, Huber J D, Sanders R B
J Am Vet Med Assoc. 1986 Sep 1;189(5):547-9.
Fifty-six heifers were weaned from dams that were card-test positive for brucellosis. Forty-four dams were positive by rivanol and complement-fixation tests and Brucella abortus field strain was isolated from 14. Numbers of expected pregnancies following natural breeding and numbers of viable calves produced were not reduced in the heifers. Persistent B abortus infection was documented in 2 of 37 parturient heifers from reactor dams. The frequency of infection was 1 of 10 in strain 19-vaccinated heifers, and 1 of 27 in nonvaccinated heifers. The 2 persistently infected heifers had atypical serologic reaction patterns before normal parturitions.
56头小母牛在出生时其母亲布鲁氏菌病平板凝集试验呈阳性。44头母牛通过利凡诺和补体结合试验呈阳性，并且从14头母牛中分离出流产布鲁氏菌田间菌株。这些小母牛自然配种后的预期怀孕数量以及存活小牛数量并未减少。在来自反应母牛的37头分娩小母牛中，有2头被证实存在流产布鲁氏菌持续感染。19号菌株疫苗接种的小母牛感染频率为十分之一，未接种疫苗的小母牛感染频率为二十七分之一。这2头持续感染的小母牛在正常分娩前有非典型血清学反应模式。
