PATHOGENICITY OF DAILY INTAKES OF COOPERIA-ONCOPHORA LARVAE IN GROWING CALVES
PATHOGENICITY OF DAILY INTAKES OF COOPERIA-ONCOPHORA LARVAE IN GROWING CALVES
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DOI：
10.1016/0304-4017(79)90015-3
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发表时间：
1979-01-01
影响因子：
2.6
通讯作者：
ANGUS, KW
中科院分区：
文献类型：
--
作者：
COOP, RL;SYKES, AR;ANGUS, KW
三组，每组4个半月。饲喂自由采食全反刍动物饲料，每周5天，饲喂0、5000、10,000或20,000尾红鳍金鱼幼虫，每周5天，共20周。在最后一次注射幼虫后2周处死所有幼崽。铜绿假单胞菌感染降低了13.5%的增重，但对干物质的自愿摄入量没有显著影响，也没有产生任何明显的临床症状。幼虫摄食率与虫量或粪卵数之间没有明显的关系。大多数感染的牛犊在8-10wk时产生了一定程度的获得性抗性。屠宰时，4头犊牛以4龄早期幼虫为主，肠道最大虫体回收率仅为幼虫总摄入量的1.5%。十二指肠和空肠前段多见。病理改变仅限于蠕虫周围区域，仅包括与寄生虫接触的绒毛受压和变形。接种20000尾幼虫/日组在接种后7~13wk出现轻度低蛋白血症。对血清总蛋白、球蛋白、尿素、钙、镁、铅浓度及骨骼成分无显著影响。
Groups of three 4 1/2 mo. old calves were offered a complete ruminant diet ad libitum and given, on 5 days each week for 20 wk, either 0, 5000, 10,000 or 20,000 C. oncophora larvae. All calves were killed 2 wk after receiving the last dose of larvae. Cooperia infection reduced liveweight gain by 13.5% but did not significantly affect voluntary dry matter intake or produce any obvious clinical signs. No relationship was evident between the rate of larval intake and worm burden or fecal egg count. A degree of acquired resistance developed in the majority of infected calves by 8-10 wk. At slaughter, early 4th stage larvae predominated in 4 calves and maximum worm recoveries from the intestine were only 1.5% of the total larval intake. The majority of Cooperia were located in the duodenum and anterior jejunum. Pathological changes were restricted to areas surrounding the worms and consisted only of compression and distortion of villi in contact with parasites. Slight hypoalbuminemia occurred between 7-13 wk post inoculation in the group which received 20,000 larvae/day. There were no significant effects on serum total protein, globulin, urea, Ca, Mg or Ph concentrations, or skeletal composition.