Mating Awassi rams to Merino ewes causes an initial level of fibre contamination which decreases to an insignificant level eight weeks post-mating

Abstract

The fleeces of Merino ewes mated by Awassi rams were analysed for the presence of contaminant fibres (pigmented, urine-stained and kemp). In a controlled shed mating, high numbers of contaminant fibres were found in the fleeces of the ewes, with the number of fibres transferred being proportional to the number of times the ram mounted the ewe. The number of fibres transferred during the shed mating were substantially higher than those found after paddock mating. In the latter instance, environmental conditions and contact with other sheep would have contributed to the loss of fibres from the recipients’fleeces. Each ram breed used in the paddock mating experiment, Merino, Awassi and Suffolk, transferred fibres into the fleeces of the mated ewes. The Suffolk transferred relatively more fibres than both the Awassi or the Merino rams, in addition the fibres from the Suffolk were significantly darker than those from the other breeds thus compounding the severity of the contamination. Both mating experiments demonstrated that the number of contaminant fibres remaining in the ewe’s fleece 8 weeks after mating was not different to that existing in the fleece of the ewes before mating. Therefore, in commercial flocks, the risk of contamination can be minimised by shearing breeding ewes 8 weeks after rams have been removed from the breeding flocks.