Previous Awassi grazing on a paddock or grazing in the same or adjoining paddock, does not cause fibre contamination of fleeces of Merino sheep

The fleeces of Merino wethers grazed either in common or adjacent paddocks with Awassi rams were analysed for the presence of contaminant fibres (pigm ented, urine-stained and kemp). In addition, the effect of previous grazing history of the paddock (i.e. whether or not that paddock had been previous ly grazed by Awassi sheep) on the level of fibre contamination was also inv estigated. Under extensive grazing conditions, very few Awassi contaminant fibres were transferred into the Merino fleeces. In fact, there was no sign ificant difference between the control group, grazed outside the quarantine facility, and any of the treatment groups grazing within the quarantine ar ea. The previous grazing history of the paddock had no effect on the number of contaminant fibres transferred, suggesting that even if contaminant fib res fall onto the paddock, they do not contaminate the fleeces of Merino sh eep that subsequently graze that paddock. Up to 100% of the contaminant fib res transferred into the Merino fleeces were lost within 4 weeks after the removal of the Awassi rams from the paddocks. Therefore, withholding sheari ng of Merino sheep for 4 weeks after any contact with Awassi sheep would be sufficient for the level of contaminant fibres in the greasy fleece to fal l to below commercially acceptable limits for dark fibres in worsted proces sing.