Abstract
Extract In considering any system of parasite control by management, it is useful to have a reasonably clear conception of the problem involved. Taylor (1957) Taylor, E. L. 1957. Vet. Rec., 69: 557–557. [Google Scholar] has given some idea of the enormous biotic potential of the gastro-intestinal parasites of sheep. A sheep carrying quite a moderate infestation will distribute some 500,000 worm eggs each day on to the pasture it is grazing. Moreover, with present-day trends in farming efficiency, it is as well to know that, on any given area, these parasites tend to increase as the square of the number of animals depastured on it.