Lamb Liveweight Gain Research Articles

A study of subclinical worm infestation in sheep: Part II. The ‘tolerance’ level of infestation

1. The live-weight gain of lambs initially infected at five different levels was compared with that of similar but worm-free animals, under conditions of set-stocking at a high rate per acre.2. Over a period of 9 months the worm-free controls gained 67·7% more weight than the total infected group, but the live-weight gains of the five levels did not appear to be related to their original infection or to their egg counts.3. Although a few nematode eggs were detected in the faeces of some control lambs, reinfection was negligible under the conditions of this experiment.4. It was concluded that a marked depression of productivity may be associated with an egg count as low as 114 e.p.g. in sheep 4–7 months of age.