Impact of bacteria and coccidia on scouring & productivity in sheep (5485) (AWI - ON- 00051)

Summary

Intestinal parasites cost the Australian sheep industry an estimated $436 million per annum, yet little is known about the contribution of protozoan parasites and bacteria to scouring and production loss in sheep.

Objectives

This project aimed to:

• Develop a high throughput multiplex quantitative PCR (qPCR) to detect and quantify the pathogen load of 10 pathogens (Salmonella, Campylobacter, Yersinia, Chlamydia, Eimeria, Cryptosporidium, Giardia, Haemonchus, Teladorsagia and Trichostrongylus) in sheep faeces across four states; Western Australia (WA), New South Wales (NSW), South Australia (SA) and Victoria (Vic).
• Develop genotyping tools for these pathogensIdentify any significant associations between pathogens and production parameters
• Develop a qPCR assay for Escherichia coli O157:H7 and determine the prevalence and pathogen load of zoonotic pathogens (Salmonella, Campylobacter, Cryptosporidium, Giardia and Escherichia coli O157:H7) using qPCR in sheep faeces collected from WA sale yards (Muchea and Katanning) and in abattoir effluent (Katanning) (inlet and outlet).

Three multiplex assays were successfully developed, validated and used to determine the prevalence and pathogen load per gram of faeces (g-1) of the ten pathogens (Salmonella, Campylobacter, Yersinia, Chlamydia, Eimeria, Cryptosporidium, Giardia, Haemonchus, Teladorsagia and Trichostrongylus) from 3,412 sheep faecal samples collected from 1,189 lambs on three sampling occasions (weaning, post-weaning and pre-slaughter) from eight farms across the four states.

Key findings

Analysis revealed that there were distinct differences in prevalence between pathogens across the four states. In general, bacterial pathogens were more prevalent in Eastern states than in WA. Salmonella had the lowest prevalence of all pathogens across the four states. Cryptosporidium and Giardia were more prevalent in WA than Eastern states and Eimeria was most prevalent in NSW.  With the exception of Haemonchus, the prevalence of strongyle worms was high across most states. Chlamydia abortus was not detected in Australian sheep.