牛传染性鼻气管炎的潜伏感染和检疫

这是联邦德国汉诺威兽医大学病毒学研究所所长B.Liess博士来我国讲学的一部分学术资料,现整理发表.供同志们参考. 牛传染性鼻气管炎(IBR)在欧美牛群中普遍存在,在联邦德国于25年前第一次分离出IBR病毒。一般讲,IBR分急性和慢性病例,病的后期往往难以分离出病毒;另外,慢性病例如有细菌性并发感染,易于诱发肺脓肿病灶。还有些病牛,症状似牛恶性卡他热(BMC),其病原也是牛疱疹病毒,     

高速气流对肉仔鸡生产性能的影响

用1484只罗斯雄仔鸡分两组试验,以研究气流速度为180m/min和120m/min时,与静止气流(<15m/min)相比,其对3～7周龄仔鸡增重(BWG)和饲料报酬(F/G)的影响。肉鸡在普通环境中养殖3周龄。试验设施为一四边关闭的房子,内有8个在通风管内的地板式围栏(2个通风管×4个围栏/通风管)和6个没有通风的围栏。通风管设置两种风速:180或120m/min。3周龄时,每栏放入53只鸡,再放入通风管中,其他6栏置于环境控制设施中。栏的地板面积为3.75m~2,一根喂料管,一个食槽。温度控制模式为每日25～30～75℃循环,露点为23℃。结果表明,在第一周(3～4周),与静流组比,180和120m/min的流速对BWG以及F/G无显著影响,但第4～5周和第5～6周,随风速增加,BWG和F/G有显著改善。最后一周,风速180m/min比120m/min显著改善BWG和F/G。     

小蔗螟抗性的广义遗传力、遗传相关和选择指数及其与产量损失的关系

由Diatraea saccharalis引起的小蔗螟对甘蔗造成了严重的损害，因而培育抗性品种非常重要。小蔗螟幼虫通过在茎秆节间钻洞和化蛹来损害甘蔗。通过机械钻洞，营养物质输送中断，直接减少了茎秆重量，严重时造成茎秆毁损。这种机械损毁作为病原体传入的通道，造成茎秆重量和品质的进一步下降。     

香甜瓜产量和产量相关性状的杂种优势

任何作物中杂种优势的开发利用前景极大地依赖于杂种优势的方向和强度以及生产杂交种子的简便程度。虽然香甜瓜(Cucumis melo L．)中有用的遗传变异幅度较宽，但很少人注意利用它。有限的杂交研究数据表明，F1杂种产量比标准品种高，因此，本研究打算收     

Effects of heartworm and intestinal parasitic infections on hematology and peripheral lymph node cytology in louisiana dogs

Hookworm infected dogs had higher blood basophil counts than hookworm negative dogs. Dogs with occult heartworm infection (i.e., without microfilaremia) had higher blood neutrophil counts than heartworm negative dogs. The percentage of eosinophils in peripheral lymph nodes was higher in heartworm infected, microfilaremic dogs than in both occult infected dogs and heartworm negative dogs. Heartworm or intestinal parasitic infection had no other significant effects on hematologic parameters or peripheral lymph node cytology.     

Rabies diagnosis in western Canada, 1985-1989

The results of laboratory examination of 20460 specimens for the diagnosis of rabies by the standard fluorescent antibody and mouse inoculation tests over a five year period are presented. Specimens were received from British Columbia, Alberta, Saskatchewan, Manitoba, and the Yukon and Northwest Territories. Of those examined, 9.96% were positive. The main reservoirs of rabies were skunks, bats, and foxes. During this observation period a rabies epizootic occurred in skunks in Saskatchewan. When both tests were performed, the fluorescent antibody test was found to agree with the mouse inoculation test in over 99% of cases.