Abstract
Extract A previous paper (Brunsdon, 1963b Brunsdon, R. V. 1963a. N.Z. vet. J., 11: 86–86. [Taylor & Francis Online] [Google Scholar] ) re-ported the results of a trial undertaken in 1961–62 to ascertain the effects of a naturally acquired mixed trichostrongyle infestation on the liveweight gain and wool production of sheep during their first year of life. At the conclusion of that trial, lambs in which infestation had been almost completely suppressed by fortnightly drenching showed a very marked liveweight gain response over infested control animals grazing the same pasture. Furthermore, an increase in clean fleece weight of 33% was recorded in favour of the drenched group. The results suggested that the cumulative effects of trichostrongyle infestation are much greater than the results of short-term drenching trials have previously indicated. Also it was suggested that trichostrongyle infestation may play a greater role in hogget unthriftiness than had been considered previously.