给怀孕母猪口服调痢生预防仔猪黄、白痢病

将农村中品种、胎次相同的60头怀孕母猪分为三组进行试验。试验结果表明,给产仔前5天的怀孕母猪口服调痢生,按每公斤体重100毫克剂量,每日一次,连用5天,对预防其所产仔猪不患黄、白痢病具有显著效果;而且仔猪增重快,药费成本低,使用方便,经济效益明显。     

A Probabilistic Model of the Economic Risk to Britain's Railway Network from Bridge Scour During Floods

Scour (localized erosion by water) is an important risk to bridges, and hence many infrastructure networks, around the world. In Britain, scour has caused the failure of railway bridges crossing rivers in more than 50 flood events. These events have been investigated in detail, providing a data set with which we develop and test a model to quantify scour risk. The risk analysis is formulated in terms of a generic, transferrable infrastructure network risk model. For some bridge failures, the severity of the causative flood was recorded or can be reconstructed. These data are combined with the background failure rate, and records of bridges that have not failed, to construct fragility curves that quantify the failure probability conditional on the severity of a flood event. The fragility curves generated are to some extent sensitive to the way in which these data are incorporated into the statistical analysis. The new fragility analysis is tested using flood events simulated from a spatial joint probability model for extreme river flows for all river gauging sites in Britain. The combined models appear robust in comparison with historical observations of the expected number of bridge failures in a flood event. The analysis is used to estimate the probability of single or multiple bridge failures in Britain's rail network. Combined with a model for passenger journey disruption in the event of bridge failure, we calculate a system‐wide estimate for the risk of scour failures in terms of passenger journey disruptions and associated economic costs.     

仔猪大肠埃希氏三价灭活菌苗预防仔猪黄白痢的效果分析

本试验采用大肠埃希氏三价灭活菌苗预防仔猪黄白痢，结果表明：初生仔猪发病率由45．4％降为19．4％（P≤0．01），死亡率由43．5％降为7．5％（P≤0．01），而且0－7日龄仔猪的发病率由31．9％降为2．7％（P≤0．01），治愈率由48．7％上升为85．7％（P≤0．01）     

河道中钝体周围的床面冲刷试验研究

对泄洪闸闸墩、淹没薄壁长立方体以及圆柱形桥墩周围的河床床面冲刷进行了较为详细的试验。以试验所获得的大量测试数据、录像资料及照片为基础,分析了钝体周围的水流速度场、水流旋涡场、并重点分析了钝体周围的床面冲刷与钝体周围水流旋涡结构的关系,得出了关于河道中钝体周围床面冲刷的一些规律性结论。     

猪场新生仔猪黄痢的病原分离及药敏试验

从重庆市几个规模化猪场的发病仔猪中采集病料,分离培养的病原菌,在麦康凯培养基上菌落呈红色,革兰氏染色为G-菌,生化试验结果显示对葡萄糖、乳糖、麦芽糖产酸产气,不分解尿素,不产生硫化氢,表明所分离菌为大肠杆菌。用分离菌对头孢唑啉等29种药物进行药敏试验,所分离的大肠杆菌对头孢类药物、氧氟沙星、氨苄西啉等药物高度敏感,而对链霉素、替硝唑产生耐药性。但从不同场分离到的菌株对药物的敏感性不一致。