Abstract
Extract The pathogenic significance of Ostertagia ostertag to cattle has been well established by many workers overseas (see Brunsdon ( 1968 Brunsdon, R. V. 1968. Trichostrongyle worm infection in cattle: Ostertagiasis — effect of a field outbreak on production, with a review of the diseases syndromes, problems of diagnosis and treatment. N.Z. vet. J., 16: 176–187. [Taylor & Francis Online] [Google Scholar] ) for review) and in New Zealand (Brunsdon, 1968 Brunsdon, R. V. 1968. Trichostrongyle worm infection in cattle: Ostertagiasis — effect of a field outbreak on production, with a review of the diseases syndromes, problems of diagnosis and treatment. N.Z. vet. J., 16: 176–187. [Taylor & Francis Online] [Google Scholar] , 1969 Brunsdon, R. V. 1969. Trichostrongyle worm infection in cattle: Ostertagiasis and concurrent infections in dairycalves: Seasonal patterns of occurrence, pathology and diagnosis. N.Z. vet. J., 17: 161–171. [Taylor & Francis Online] [Google Scholar] ).