Abundance and distribution of microbial populations in sheep fleece

Abstract

Bacteria were isolated and enumerated from fresh wool samples from sheep flocks throughout New Zealand. Bacterial populations averaged 108‐109 colony forming units (cfu) g‐1 wool and varied little between flocks. Highest numbers of bacteria were recovered from the back, neck, and rump of the sheep rather than the underside of the animal. Within the fleece, most bacteria (>95% of total) were isolated from the outer portion of the staple. The fleece bacteria could be divided into three broad classes, Gram‐positive cocciform bacteria, Gram‐positive rods, and Gram‐negative rods. Most bacteria from the fleece formed pigmented colonies with colours ranging from yellow to bright red. Gram‐positive cocciforms were the most abundant group of bacteria with the most common species corresponding to Kocuria rosea, Micrococcus luteus, and M. lylae. These species form a dominant complex of salt tolerant chromogenic bacteria which are characteristic of the healthy fleece.