Gibson T E, Everett G
Res Vet Sci. 1978 Mar;24(2):169-73.
Three groups of lambs were given 50, 250 or 2800 infective larvae of Ostertagia circumcincta per day for a period of six weeks. All groups then received 25,00 larvae per day for a similar period and observations were continued for a further six weeks. Egg output following the initial infection varied directly with the level of larval intake, but fell to a low during the second period of infection and decreased still further in the final six weeks of the observation. The investigation suggests that, provided high levels of residual larval infection on pasture are avoided, there appears to be considerable merit in exposing lambs to a low level of initial infection.
三组羔羊每天分别接种50、250或2800个环纹奥斯特线虫感染性幼虫，持续六周。之后，所有组在相似时间段内每天接种2500个幼虫，并继续观察六周。初次感染后的产蛋量与幼虫摄入量直接相关，但在第二次感染期间降至较低水平，并在观察的最后六周进一步下降。该研究表明，只要避免牧场中存在高水平的残留幼虫感染，让羔羊接受低水平的初次感染似乎有很大益处。
