Population evolution of the free-living stage of goat gastrointestinal nematodes on herbage under tropical conditions in Guadeloupe (French West Indies).

In Guadeloupe (French West Indies), paddocks were contaminated with gastrointestinal helminth eggs by young goats during the rainy season and the dry season. The evolution of L3 population size on herbage was followed over a period of 56 days. The major genera were Haemonchus and Trichostrongylus. It was shown that the L3 appeared on herbage 7-14 days after the beginning of contamination (DAC), and the L3 population sizes were maximal between the 14th and the 21st DAC. The maximum duration of larval survival ranged between 49 and 56 days. There was a marked depressive effect by the dry season on eggs hatching and L3 development with some arrested egg hatching in Trichostrongylus. The climatic events and the amount of dry matter on pastures during the grazing period appeared as the main important factors which could interfere with the overall evolution of the L3 population size and there was no preferential direction of L3 migration from faeces to herbage.