Descriptive findings from analysis of a large database of cattle worm egg count and larval culture results collected across Australia between 2002 and 2012

摘要

Results from worm egg counts (WECs) of cattle from across Australia over an 11 year period have been analysed to provide contemporary data on WEC and worm genus distribution in Australian cattle. A sampling kit consisted of ten sample containers. Faecal samples were collected into each sampling kit from groups of cattle and WEC and larval cultures were conducted using standard procedures. A submission form was completed for each kit with data requested including date of sampling, property address, age, average estimated weight and production type of cattle, last drench used and date of drenching. Regional analysis was done by postcode region and postcode regions were grouped into bioclimatic regions. A total of 5069 submissions were received from 2002 to the end of 2012 representing over 50,000 individual faecal samples. Seventy-seven percent of cattle sampled were no more than 2 years of age with the remainder representing a range of age groups. Samples were collected from all of the significant cattle producing regions of Australia. There was a tendency for higher geometric mean WEC in cattle in northern Australia and in high rainfall areas along the east coast of Australia. Geometric mean WEC for bioclimatic regions varied seasonally with a peak in autumn in regions with summer dominant rainfall, but little seasonal variation in regions with winter dominant rainfall patterns. Worm genera cultured varied throughout Australia with Cooperia spp. being most prevalent across the country, followed by Haemonchus spp. and Oesophagostomum spp. in summer rainfall dominant regions and Ostertagia spp. and Trichostrongylus spp. in winter rainfall regions. In the coastal, tablelands, and temperate rangelands regions of NSW, Haemonchus spp. were as prevalent as Cooperia spp. during autumn months and levels of Haemonchus spp. found in south-western Western Australia were higher than previously documented. These data provide an up-to-date summary of internal parasites in Australian cattle. Regional differences in WEC between northern and southern Australia are evident and should be further explored. These data suggest that there has been a move to Cooperia spp. being the predominant worm genus in Australian cattle, with increasing levels of Haemonchus spp. being evident in southern temperate regions of Australia