Animal Science, School of Environmental and Rural Sciences, University of New England, Armidale, NSW 2351, Australia.
Vet Parasitol. 2013 Feb 18;192(1-3):199-210. doi: 10.1016/j.vetpar.2012.10.015. Epub 2012 Oct 24.
Three climate-controlled chamber experiments were conducted to determine the effect of 32 mm simulated rainfall applied prior to (days -4 to -1) or after (days 0-7) faecal deposition and as a single (32 mm) or split (2 × 16 mm) application on faecal moisture (FM) and development of H. contortus and T. colubriformis to third stage infective larvae (L3). The timing of simulated rainfall regulated extra-pellet L3 recovery for H. contortus (P<0.05) but not T. colubriformis. Recovery of L3 was highest (P<0.05) when simulated rainfall was applied on the day of deposition followed by days -1, 1 and 2, which resulted in similar but lower development success rates. Recovery of intra-pellet T. colubriformis L3 was two-fold greater (P=0.008) than for H. contortus and was higher (P=0.007) following simulated rainfall on days 0 and 1 than on other days. There was a positive association between FM and total L3 recovery indicating the importance of FM in the period 48-72 h (H. contortus) and 72-96 h (T. colubriformis) after deposition. Simulated rainfall on the day prior to deposition was as effective in supporting total L3 recovery as application on days 1 or 2 and this effect could be predicted through FM. This highlights the importance of soil in transferring moisture to the faecal pellet. The importance of precedent rainfall and soil moisture in determining the development success of H. contortus and T. colubriformis, in addition to the general effects of the timing of simulated rainfall, need to be accommodated in grazing management programs to combat these species.
进行了三个气候控制室实验，以确定在粪便沉积前（-4 至-1 天）或后（0-7 天）应用 32 毫米模拟降雨，以及作为单次（32 毫米）或分两次（2×16 毫米）应用对粪便水分（FM）和旋毛虫和结肠小袋纤毛虫发育到第三阶段感染性幼虫（L3）的影响。模拟降雨的时间安排调节了旋毛虫（P<0.05）但不是结肠小袋纤毛虫的额外粪球内 L3 回收。当模拟降雨在沉积当天应用，随后是-1、1 和 2 天时，L3 的回收最高（P<0.05），导致类似但较低的发育成功率。粪球内结肠小袋纤毛虫 L3 的回收量是旋毛虫的两倍（P=0.008），并且在模拟降雨后在 0 天和 1 天比在其他日子更高（P=0.007）。FM 与总 L3 回收之间存在正相关关系，表明 FM 在沉积后 48-72 小时（旋毛虫）和 72-96 小时（结肠小袋纤毛虫）期间的重要性。在沉积前一天进行的模拟降雨在支持总 L3 回收方面与在第 1 天或第 2 天应用一样有效，并且可以通过 FM 预测这种效果。这强调了土壤在将水分转移到粪便球中的重要性。除了模拟降雨时间的一般影响外，先前降雨和土壤水分在确定旋毛虫和结肠小袋纤毛虫的发育成功率方面的重要性需要在放牧管理计划中得到考虑，以对抗这些物种。
