Optimal strategies for combined control of internal and external parasitesof cattle

This review of the epidemiology, of important internal parasites and the li fe cycles of internal parasites of cattle has identified some salient point s which provide the basis for strategies designed to optimize the effective ness of parasite control while maximizing return on investment. Based on th is review, it appears that specific control measures should he used at stra tegic times of the year to more effectively control internal and external p arasites according to our knowledge of the epidemiology and life cycles of the parasites. If properly timed strategic worm control programs are utiliz ed, endecticides can add cost to the program without improving effectivenes s. Based on this review of the epidemiolog of internal parasites and the li fe cycles of external parasites, it would appear that the use of endecticid es when not warranted results in the "wasting of activity". The selection o f treatments for optimizing strategies to control internal and external par asites of cattle should be based on the parasite to be controlled the spect rum of activity and the cost of any treatment.