Nematoda, Volume 3; doi:10.4322/nematoda.00116
One of the major challenges facing beef cattle farming in Brazil, with the current situation of inefficacious anti-helminthic treatments and the absence of any prospect for new molecules appearing on the market, is sustainable control for gastrointestinal verminosis. The proposals currently being studied and those already evaluated show that the most coherent way in which to control gastrointestinal nematodes efficiently is by understanding their biology more thoroughly. There should be an emphasis on the free-living phases observed in the pasture microhabitat, which is directly influenced by climatic factors, among which temperature and humidity stand out. To a lesser degree, barometric pressure, solar ray incidence, cloud cover, evaporation, wind, quantity of vegetation and some other factors may interfere directly in their migration, survival and maintenance and, consequently, influence the rate of infection. The isolation of each environmental variable to determine its level of interference in the behavior of larvae in the pastures under field conditions is a practice that has not so far been accessible. Knowledge about climatic variations may be used as an important tool in the correct implementation of control strategies that aim to make intelligent use of anti-helminthic treatments, reducing the risk of animal infection and increasing the number of parasites in refugia. However, new field studies are still necessary to clarify the real contribution that each climate variable makes to the behavior of larvae in the pasture and their impact on the increased risk of infection and animal parasite burden.