Effects of level of nutrition and drenching strategy on pasture utilization during autumn by set-stocked hoggets infected with gastro- intestinal nematodes

K.T. Jagusch, P.V. Rattray, M. Petch and A. Vlassoff

Ruakura Animal Research Station, Hamilton and Wallaceville Animal Research Centre, Upper Hutt

Proceedings of the New Zealand Society of Animal Production. 1980, 40: 12-17

In a 3x3 factorial trial, set-stocked ewe hoggets were offered pasture allowances of 2, 4, or 6 kg DM/head/day for 10 weeks during autumn 1979 and either given no anthelmintic or treated at 5- or 2.5- week intervals. Initially Trichostrongylus spp. were the major parasites, comprising 86% of the mean faecal egg count of 4000 e.p.g., and 53% of the 450 larvae/kg herbage. However, the proportion of Haemonchus contortus increased during the trial. There was apparent resistance to the drench and large numbers were present in most groups at slaughter. Subclinical parasitism had little effect on intake and utilisation of pasture. Substantial liveweight responses to drenching at the higher levels of nutrition could be due to better digestive or metabolic efficiency. Higher planes of nutrition reduced faecal egg counts and pasture larval levels for undrenched stock, and the animals gained weight.

Keywords: NZSAPAB;

Last Updated 12-09-1998