Biggs, H.C.; Anthonissen, M.; Steyn, P.J.J.; Bigalke, R.D.; Cameron, Colin McKenzie; Gilchrist, Frances M.C.; Jordaan, E.; Morren, A.J.; Verster, Anna J.M.; Verwoerd, Daniel Wynand; Walker, Jane B.
(Published by The Government Printer, Pretoria, 1982)
The seasonal incidence of gastro-intestinal helminths and of Oestrus ovis was determined by slaughter of successive groups of 4 tracer lambs, each exposed on pasture for 33 days.
Haemonchus contortus was present from March ...