Further studies of the effect of infestation by nematodes of the family Trichostrongylidae in sheep: an evaluation of a strategic drenching programme.

Abstract

Abstract Extract The high efficiency of some of the newer anthelmintic drugs has shown them to be extremely useful as research tools in field studies of the pathogenicity of naturally-acquired mixed trichostrongyle infestations. With the advent of these drugs, which are highly effective against both the adult and the larval forms of all the common trichostrongyle species occurring in sheep, it has now become feasible to attempt to suppress almost completely worm infestation in sheep on pasture. Previous papers (Brunsdon, 1963 Brunsdon, R. V. 1963. The effect of infestation by nematodes of the family Trichostrongylidae upon the liveweight gain and wool production of young sheep. N.Z. vet. J., 11: 144–148. [Taylor & Francis Online] , [Google Scholar], 1964 Brunsdon, R. V. 1964. The effect of infestation by nematodes of the family Trichostrongylidae and the tapeworm Moniezia expansa, upon the live-weight gain and wool production of young sheep. N.Z. vet. J., 12: 129–134. [Taylor & Francis Online] , [Google Scholar]) reported the results of two trials undertaken during 1961–2 and 1962–3 to ascertain the effect of trichostrongyle infestation in young sheep. In these trials, half of the flock was subjected to a programme of fortnightly drenching with thiabendazole. The response obtained in these animals was measured in terms of liveweight gain and wool production, by comparison with that of untreated control animals grazing the same pasture. In this way, a base line of comparison was obtained which makes possible an evaluation of the effects of infestation during the first year of life.