Criteria for deworming beef cattle under ranch conditions

Anthelmintics provide the cattle farmer with a means of controlling worm infestations. Whether their use is economical depends upon how it is integrated with climatic changes, pasture management, and the immune state of the animals Preventive deworming based on a system which monitors worm burdens is idealistic and generally impractical. Monitoring systems which have been employed include faecal egg counts and cultures, haematological determinations, and worm recoveries post mortem. An efficient method of deworming beef cattle is the use of a strategic drenching programme, based upon seasonal variations in the incidence of the helminths. The economics of this approach can be improved by a tactical drenching programme in which the timing of drenches is dictated by factors which could lead to an outbreak of helmninthosis. The most efficient method is dosing which keeps pastures free from contamination over longer periods.