Effect of herbage species and renewal technique on the free living stages of gastro‐intestinal roundworms

Abstract This experiment assessed the effect of commonly used pasture species and their establishment technique on endoparasites on herbage in Canterbury, New Zealand. Pasture plots were artificially contaminated with lamb faeces with a known endoparasite egg count. Subsequent treatments included retaining the original pasture, replacing the pasture immediately with new pasture via cultivation or direct‐drilling, replacing the pasture immediately with a brassica via cultivation or direct drilling, or replacing the pasture immediately with a barley grain crop via cultivation. Brassica and grain crops were later replaced with new pasture. Herbages were harvested and dry matter (DM) yield and numbers and species of endoparasites (L 3 ) were determined. Pasture and brassica establishment technique had no effect on herbage production. The old pasture initially contained more L 3 than all other treatments, but subsequently had a similar number to pasture renewed by direct drilling, both of which had considerably more than all other treatments. Establishing new pasture by direct drilling resulted in 12 760 L 3 /kg DM over 56 weeks, nearly three times more than occurred following cultivation. Brassica swards had fewer L 3 than did new grass. Nematodirus L 3 were disproportional to the number of eggs deposited; they represented 2% of the eggs deposited but 67% of the L 3 , and they were more persistent, representing 30% of the L 3 present during March but 87% during October.