Internal parasites of sheep and their effects on production

R.V. Brunsdon

Wallaceville Animal Research Centre, Wellington

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Proceedings of the New Zealand Society of Animal Production. 1966, 26: 165-181

Sheep in which infestation had been almost completely suppressed by fortnightly drenching with thiabendazole showed a mean liveweight-gain response of up to 31 lb over infected control animals grazing the same pasture. In the untreated control groups, mortalities of up to 11% could be directly attributed to worm infestation. Increases of up to 2.6 lb or 46% in greasy-fleece weight were recorded in favour of the treated groups. Monthly sampling showed that differential wool growth was greatest from April to August, wool production in the drenched group being almost twice that of the untreated animals.

Faecal egg counts of control animals showed a relatively constant pattern, from which it is seen that the highest levels of infestation usually occurred in the months of March, April and May.

A strategic drenching programme of three drenches at monthly intervals, commencing in March, resulted in a mean response of 15 lb liveweight together with an increase of 1.2 lb greasy wool.

The results demonstrate the possible major role of trichostrongyle infestation in the hogget ill-thrift problem, and provide evidence of greater economic loss in meat and wool production than has previously been considered.

Keywords: NZSAPAB;