The Epidemiology and Control of Nematode Infections in Cattle

The intensity of the parasite problem with grass-fed cattle is generally a function of the intensity of the enterprise. Worm burdens acquired under favourable climatic conditions may have an economically significant effect, depending on the numbers acquired, and the age and "resistance" of the host. In special circumstances, because of the phenomenon of hypobiosis (arrested larval development), certain parasites may not exert pathogenic effects until many months after they have been acquired. This fact has special implications in control in specific management situations.