Simon R, Aumont G, Aprelon R, Barré N
Institut National de la Recherche Agronomique Unité de Recherches Zootechniques, Pointe à Pitre, Guadeloupe, French West Indies.
Ann N Y Acad Sci. 1996 Jul 23;791:412-20. doi: 10.1111/j.1749-6632.1996.tb53548.x.
The objective of this study was to determine the main sources of variation in herbage densities of infective third stage larvae of goat strongyles during the marked dry season of 1994 in Guadeloupe (FWI). Herbage samples were collected for L3 density (LD) determination by an accurate method, 4 times at 4-week intervals in 58 paddocks of 21 farms spread out in five regions of the archipel of Guadeloupe. At the same time, FEC of each grazing animal and fecal culture for parasite genus determination according to sex and age were carried out. Stocking rate, dry matter content of soil, and daily climatic data were also recorded. An index of egg development in larvae (IEDL) was calculated as the ratio of LD to the eggs deposed during the 4th, 3rd, and 2nd weeks before sampling. Medians of LD in herbage were 3397, 1853, 1410, and 324 L3/kg DM for all parasites, Haemonchus, Trichostrongylus, and Oesophagostomum, respectively. Date of sampling, region, and irrigation practice in the northern windward region were the main sources of variation in LD and in frequency of each parasite. LD decreased as the dryness lasted, but it remained important (500 L3/kg DM) despite the drought. LD in windward regions were higher than in other regions. The region, the farm, and the paddock were the main sources of variation of IEDL. LD of each parasites were inversely correlated to global radiation recorded 1 to 3 weeks before herbage sampling, but no relation was found with rainfall data. Trichostrongylus frequency in L3 population increased as the dryness lasted. A dryness axis was extracted from environmental variables (climatic data, dry matter of soil, duration of dryness) by a multiple factorial procedure. LD and Haemonchus frequency in L3 population were inversely correlated to dryness axis (p < 0.01). In contrast, Trichostrongylus frequency was positively correlated to the dryness component.
本研究的目的是确定1994年瓜德罗普岛（法属西印度群岛）明显旱季期间山羊圆线虫感染性第三期幼虫牧草密度变化的主要来源。通过一种精确的方法采集牧草样本以测定第三期幼虫密度（LD），在瓜德罗普岛群岛五个区域的21个农场的58个牧场中，每隔4周采集一次，共采集4次。同时，对每只放牧动物进行粪便虫卵计数（FEC），并根据性别和年龄对粪便进行培养以确定寄生虫种类。还记录了载畜率、土壤干物质含量和每日气候数据。幼虫卵发育指数（IEDL）计算为采样前第4、3和2周期间的LD与产卵量之比。所有寄生虫、血矛线虫、毛圆线虫和食道口线虫在牧草中的LD中位数分别为3397、1853、1410和324条第三期幼虫/千克干物质。采样日期、区域以及背风北部地区的灌溉方式是LD和每种寄生虫频率变化的主要来源。随着干旱持续，LD下降，但尽管干旱，其仍保持在较高水平（500条第三期幼虫/千克干物质）。背风地区的LD高于其他地区。区域、农场和牧场是IEDL变化的主要来源。每种寄生虫的LD与牧草采样前1至3周记录的全球辐射呈负相关，但未发现与降雨数据有关。随着干旱持续，第三期幼虫群体中毛圆线虫的频率增加。通过多因素分析程序从环境变量（气候数据、土壤干物质、干旱持续时间）中提取了一个干旱轴。第三期幼虫群体中的LD和血矛线虫频率与干旱轴呈负相关（p < 0.01）。相反，毛圆线虫频率与干旱成分呈正相关。
