Transfer of contaminant lamb fibres to their dam’s fleece, and loss within four weeks of weaning

Abstract

The fleeces of Merino ewes suckled by Awassi, Awassi × Merino or Merino lambs were analysed for the presence of contaminant fibres (pigmented, urine-stained and kemp). Contaminant fibres were transferred from the fleeces of all 3 lamb genotypes into the fleeces of their dams, with direct body contact being the principle method of fibre transfer. The pattern of the transfer between birth and weaning was highly variable, although there was a general trend of increasing amount of transfer with advancing lamb age, suggesting a continual cycle of transfer of fibres to the dam’s fleece and subsequent 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 of the genotype of their lambs, (i.e. pure Merino or crossbred), should be delayed until 4 weeks post-weaning in order to reduce the number of contaminant fibres of lamb origin in their fleeces.