【单选题】某猪场断奶仔猪和保育猪出现发病,主要表现为体温40°C一42。5°C,食欲下降,厌食,反应迟钝,呼吸困难,咳嗽,腹式呼吸,关节肿胀,跛行甚至瘫痪,背毛粗乱,苍白贫血,眼睑周围皮下水肿,眼结膜变红,耳部皮下,腹部皮下水肿,耳尖发紫,耳朵四肢内测发绀,背部毛孔有针尖样出血,两后腿之间腹部皮肤有大量蓝紫色斑点。发病后常呈慢性经过,通常发病2天一5天后出现死亡,个别猪突然死亡,临死前侧卧或四肢呈划水样。剖...
【简答题】Directions: There are 20 blanks in the following passage. For each blank there are four choices marked A), B), C) and D) on the right side of the paper. You should choose the ONE that best fits into t...