Transfer of contaminant lamb fibres to their dam's fleece, and loss withinfour weeks of weaning

The fleeces of Merino ewes suckled by Awassi, Awassi x Merino or Merino lam bs were analysed for the presence of contaminant fibres (pigmented, urine-s tained and kemp). Contaminant fibres were transferred from the fleeces of a ll 3 lamb genotypes into the fleeces of their dams, with direct body contac t being the principle method of fibre transfer. The pattern of the transfer between birth and weaning was highly variable, although there was a genera l trend of increasing amount of transfer with advancing lamb age, suggestin g a continual cycle of transfer of fibres to the dam's fleece and subsequen t loss from that fleece. Indeed, the number of fibres transferred tended to decrease rapidly post-weaning, when the source of the contaminant fibres ( i.e. the lambs) was removed. Shearing of Merino breeding ewes, regardless o f the genotype of their lambs, (i.e. pure Merino or crossbred), should be d elayed until 4 weeks post-weaning in order to reduce the number of contamin ant fibres of lamb origin in their fleeces.