Incidence and prevalence of microbial indicators and pathogens in ovine faeces in New Zealand

The incidence and prevalence of micro-organisms in ovine faeces as potential sources of diffuse pollution to natural waters were determined. Faecal samples from lambs at slaughter (N=105) and sheep at pasture (N=220) were collected. E. coli, enterococci and Campylobacter spp. were enumerated in lambs (6.04×10⁸, 1.44×10⁷ and 3.3×10⁵ g⁻¹ respectively) and sheep (1.62×10⁷, 6.8×10⁵ and 2.08×10³ g⁻¹ respectively). Campylobacter spp., Salmonella spp. and Shiga toxin producing E. coli (STEC) were present in 80.9%, 1.9% and 3.8% of lamb samples, and 30.4%, 0% and 0.9% of sheep samples respectively. Cryptosporidium spp. and Giardia spp. were present in 28.6% and 37.1% of the lamb faecal samples, and 3.6% of sheep samples were positive for Cryptosporidium spp. The results of this study will be incorporated into models for estimating the potential impact of ovine faeces on natural waters.