Pasture populations of cattle nematode larvae in guadeloupe (French West Indies)

Abstract The development of numbers of third-stage (L3) larvae of gastrointestinal nematodes after pat (faeces) deposition by heifers is described, using a mathematical model, for seven experiments carried out in Guadeloupe (French West Indies). A dramatic rise in L3 population size occurred on herbage near pats, 17–25 days after pat deposition. There was no clear relationship between climatic data and L3 population dynamics. However, 5 successive days of rainfall induced the resumption of larval migration in two experiments. Changing the unit of expression ofL3 population size (100 L3 m −2 vs 1000 L3 per kg DM) did not alter estimates of the model parameters. The evolution of L3 population of Haemonchus and Cooperia were similar.