Optimal strategies for combined control of internal and external parasites of cattle

This review of the epidemiology, of important internal parasites and the life cycles of internal parasites of cattle has identified some salient points which provide the basis for strategies designed to optimize the effectiveness of parasite control while maximizing return on investment. Based on this review, it appears that specific control measures should he used at strategic times of the year to more effectively control internal and external parasites according to our knowledge of the epidemiology and life cycles of the parasites. If properly timed strategic worm control programs are utilized, endecticides can add cost to the program without improving effectiveness. Based on this review of the epidemiolog of internal parasites and the life cycles of external parasites, it would appear that the use of endecticides when not warranted results in the "wasting of activity". The selection of treatments for optimizing strategies to control internal and external parasites of cattle should be based on the parasite to be controlled the spectrum of activity and the cost of any treatment.