The influence of internal parasites upon growth and productivity of weaner sheep.

Abstract

Proc. Aust. Soc. Anim. Prod. (1978) 12: 274 THE INFLUENCE OF INTERNAL PARASITES UPON GROWTH AND PRODUCTIVITY OF WEANER SHEEP R.L. THOMPSON*, J.K. EGAN* and J.W. MCLAUGHLIN Internal parasites are considered to contribute to the poor growth and productivity commonly found in young sheep in western Victoria. Whilst the problem is easily recognized in untreated animals, the extent of losses due to parasitism in flocks receiving recommended A project at Hamilton is anthelmintic treatment is not known. measuring these losses and evaluating alternative treatment programmes. Flocks of Merino lambs born in at weaning (Dee) and in late summer to five treatments, in a randomised (Table 1). All groups had initial and were set stocked at 15 ha? spring 1974 and 1975 were drenched (Feb) and allocated in groups of 12, block design with three replicates live weights of approximately 21 kg Sheep drenched weekly were assumed to be essentially worm-free wherein production was determined by genetic and nutritional factors. ,By comparison , groups drenched according to recommendations (2D) gained Molasses blocks 21023% less live weight and grew 10016% less wool. The containing phenothiazine were less effective than treatment (2D). : productivity of sheep drenched monthly (MD) or five times (SD) was similar to sheep drenched weekly. The results demonstrate that internal parasites continue to be an ' Further important source of loss, despite recommended treatment. research is required to develop more effective control measures for this region. _' * Pastoral Research Institute, P.O. Box 180, Hamilton, Vic. 3300. + Department of Agriculture, Victoria, G.P.O. Box 4041, Melbourne, 3001. - .274.