The effect of repeated moves to clean pasture on the build up of gastrointestinal nematode infections in calves
The effect of repeated moves to clean pasture on the build up of gastrointestinal nematode infections in calves
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DOI：
10.1016/s0304-4017(97)00211-2
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发表时间：
1998-03-31
影响因子：
2.6
通讯作者：
Kooyman, FNJ
中科院分区：
文献类型：
--
作者：
Eysker, M;van der Aar, WM;Kooyman, FNJ
胃肠道线虫感染的建立，其次是在两个放牧实验。这两个实验包括四组六头小牛，一个永久圈养的非感染对照组和三个组，从5月到10月放牧。其中一个在7月初被转移到善后工作，第二个在7月初和8月初，第三个在7月初、8月初和9月初。胃肠道线虫感染的建立之后，进行粪便虫卵计数、粪便幼虫培养物的分化、牧草幼虫计数、血清胃蛋白酶原值、抗肿瘤古柏线虫的血清抗体、体重增加和蠕虫计数。在第二个实验中，每组的四只主要试验动物用奥芬达唑处理，随后用100，000只奥斯特线虫幼虫攻击，以检查抗奥斯特线虫的免疫力的发展。奥斯特塔吉。粪便中的虫卵计数和7月剖检的哨兵蠕虫计数表明，在这两个实验中的初始感染率较低。实验1中的感染水平在各组中保持较低，直到9月初。然而，在过去一个月里，迁移了一次或两次的群体感染了中度至高度感染。相比之下，低至中度感染维持在组移动三次。在第二个实验中，温和的C。直到8月初，在放牧的哨兵中已经观察到了瘤菌负担。8 - 9月随群放牧的示踪剂一旦迁移，获得高O。ostertagi和C.肿瘤感染，而与其他两组一起吃草的动物则获得中度感染。在10月份，两个物种的高感染发生在一次和两次移动的群体中，而在三次移动的群体中观察到低至中度感染。攻击感染表明O.在牧场上的所有三个组中，ostertagi约为70%。结果表明，每月一次将犊牛移到清洁牧场是控制寄生虫性胃肠炎的有效方法。此外，数据表明，最后一次迁移不应超过放牧季节结束前一个月。(C)1998年Elsevier Science B.V.
The build up of gastrointestinal nematode infections was followed in two grazing experiments. Both experiments included four groups of six calves, a permanently housed non-infected control group and three groups which were grazed from May to October. One of these was moved to aftermath in the beginning of July, the second in the beginning of July and August and the third in the beginning of July, August and September. The build up of gastrointestinal nematode infections was followed by performing faecal egg counts, differentiation of faecal larval cultures, pasture larval counts, serum pepsinogen values, serum antibodies against Cooperia oncophora, weight gain and worm counts. In the second experiment four of the principal trial animals of each group were treated with oxfendazole and subsequently challenged with 100,000 larvae of Ostertagia ostertagi to examine development of immunity against O. ostertagi. The faecal egg counts and the worm counts of the sentinels necropsied in July indicated low initial infections in both experiments. Infection levels in experiment 1 remained low in each group until the beginning of September. However, during the last month, moderate to high infections were acquired by the groups which were moved once or twice. In contrast, low to moderate infections were maintained in the group moved three times. In the second experiment moderate C. oncophora burdens were already observed in the sentinels grazed until the beginning of August. Tracers grazing in August-September with the group moved once acquired high O. ostertagi and C. oncophora infections, whereas those grazed with both other groups acquired moderate infections. In October high infections with both species occurred in the groups moved once and twice, whereas low to moderate infections were observed in the group moved three times. The challenge infection demonstrated a reduction of establishment of O. ostertagi of approximately 70% in all three groups on pasture. The results demonstrate that moving calves at monthly intervals to clean pasture can be an effective method for the control of parasitic gastroenteritis. In addition, the data indicate that it is essential that the last move does not occur more than I month before the end of the grazing season. (C) 1998 Elsevier Science B.V.