The relative wool contamination potential of Awassi and black Merino sheepwhen penned together with white Merinos

Fleeces, top and finished fabric processed from white Merino (fibre recipie nt) ewes, run in close contact for 2 weeks, with either Awassi, black Merin o or white Merino control (fibre donor) ewes, were analysed for the presenc e of contaminant fibres (pigmented, urine stained and kemp). Kemp and pigme nted fibres were transferred from Awassi and black Merino sheep into the fl eeces of the recipient ewes. The concentration of kemp and pigmented fibres found in the fleeces, top and fabric of the black Merino treatment was sub stantially greater than the Awassi and Merino control groups which were not different from each other. Fibres transferred from the black Merino group were darker than those from Awassi sheep and thus posed a greater potential contamination threat. Contaminant fibres which are structurally different from the wool bulk (such as kemp) tend to be removed during worsted process ing, while those with similar dimensions (such as pigmented Merino wool fib res) are more likely to persist in the system and appear as contaminants in worsted fabric.