Anderson M L, Blanchard P C, Barr B C, Hoffman R L
California Veterinary Diagnostic Laboratory, Tulare Branch, CA 93274.
J Vet Diagn Invest. 1990 Oct;2(4):283-7. doi: 10.1177/104063879000200405.
The causes of abortion in cattle in the San Joaquin Valley of California were surveyed from submissions to the California Veterinary Diagnostic Laboratory at Tulare. Four hundred sixty-eight abortion cases were examined. Most submissions (89%) were from large drylot dairies, milking an average of 814 cows. Abortion evaluations included necropsy, histopathology, bacteriology, virology, and other immunologic and serologic tests. A specific cause was identified in 29.5% of the abortions. Bacterial infections, most of which were sporadic, accounted for 16% of all abortions. Viral causes and protozoal infections were diagnosed in 5.6% and 3.2% of the abortions, respectively. Fetuses with protozoal infection had histologic lesions of focal nonsuppurative necrotizing encephalitis, and protozoa were detected. Similar histologic lesions were seen in 80 additional fetuses (17.1%), and although an etiologic agent was not identified for these cases, a protozoal infection was suspected.
通过提交给位于图莱里的加利福尼亚兽医诊断实验室的样本，对加利福尼亚州圣华金谷地区奶牛流产的原因进行了调查。共检查了468例流产病例。大多数样本（89%）来自大型干奶牛场，平均挤奶量为814头奶牛。流产评估包括尸检、组织病理学、细菌学、病毒学以及其他免疫和血清学检测。在29.5%的流产病例中确定了具体病因。细菌感染占所有流产病例的16%，其中大多数为散发性感染。病毒病因和原生动物感染分别在5.6%和3.2%的流产病例中被诊断出来。感染原生动物的胎儿有局灶性非化脓性坏死性脑炎的组织学病变，并且检测到了原生动物。在另外80例胎儿（17.1%）中也观察到了类似的组织学病变，尽管这些病例未确定病原体，但怀疑是原生动物感染。
