Suarez V H, Lorenzo R L
Estación Experimental Agropecuaria Anguil, Instituto Nacional de Tecnología Agropecuaria, CC 11, 6326 Anguil, La Pampa, Argentina.
Parasite. 2000 Dec;7(4):255-61. doi: 10.1051/parasite/2000074255.
Development, migration and survival of infective larvae (L3) were studied in the Western Pampeana Region. Faeces of naturally nematode infected cattle were deposited as artificial pats on plots during mid-spring-summer of 1994/1995 and 1995/1996. Since the start and during 1995, the study coincided with a severe drought, rainfalls being 29% below the 45-year means. The predominant genera recovered were Cooperia, Ostertagia and Haemonchus. Initial and peak recovery of L3 from pats occurred 8-15 and 15-21 days later respectively. A low percentage of L3 survived from November (0.3% L3) and January (0.06% L3) to the following autumn and winter. The mean persistence of larvae detected in pats or herbage was around 200 days from deposition. The migration of L3 from faecal pats to herbage started 15 to 30 days after deposition according to rainfall occurrence. Maximum herbage recoveries of L3 from pats deposited in late summer occur during autumn rainfalls. Only, few L3 were occasionally recovered from soil. Summer conditions were associated with rapid development and translation of L3 to herbage, but also with low L3 detection after initial recoveries. Faecal pats deposited from mid-summer were the main source of autumn herbage contamination.
在西潘帕尼亚地区对感染性幼虫（L3）的发育、迁移和存活情况进行了研究。1994/1995年和1995/1996年春末夏中期间，将自然感染线虫的牛粪便作为人工粪堆放置在地块上。从1995年开始及整个1995年期间，该研究恰逢严重干旱，降雨量比45年平均水平低29%。回收的主要属为库珀属、奥斯特他属和血矛属。粪堆中L3的初始回收和峰值回收分别在8 - 15天和15 - 21天后出现。从11月（0.3%的L3）和1月（0.06%的L3）到次年秋冬，存活的L3比例较低。在粪堆或牧草中检测到的幼虫平均存活时间约为从放置起200天。根据降雨情况，L3从粪堆迁移到牧草开始于放置后15至30天。夏末放置的粪堆中L3在秋季降雨期间牧草中的回收率最高。仅偶尔从土壤中回收少量L3。夏季条件有利于L3快速发育并转移到牧草中，但初始回收后L3的检测率也较低。仲夏开始放置的粪堆是秋季牧草污染的主要来源。
