Studies in hogget rearing: II: The role of parasites in hogget ill-thrift

Summary Trials to determine the role of nematode parasites in the hogget ill-thrift syndrome were carried out over the years 1952-55 inclusive. Comparisons of systems of rotational grazing and set-stocking showed that rotational grazing gave no advantage over set-stocking in the level of parasitism or the thrift of the animal. Regular and frequent drenching with phenothiazine either under set-stocked or rotational-grazing management effectively reduced the level of parasitism but did not produce any worthwhile growth response in hoggets showing ill-thrift over the autumn and early winter. Drenching gave most effective control of H. contortus and was less effective against Trichostrongylus spp. Fine-particle phenothiazine (particle less than 10µ) was little more effective than coarse-particle phenothiazine in the control of H. contortus but showed a striking increase in the contro of Trichostrongylus spp. in the small intestine. The regular and frequent use of phenothiazine was shown to have no ill effects...