Factors associated with small lungworm infections in heavily infected sheep in southeast South Australia

Abstract

This field observational study describes the seasonal pattern of small lungworm infections under different grazing managements from August 2018 to March 2019. Live weight, lungworm and gastrointestinal nematode infection, as well as pasture type grazed and snail density, were measured at 5 farm visits. Across all visits and mobs, about one quarter to one half of sheep were positive for small lungworm, although prevalence was as low as 0% and as high as 78%. The density of the intermediate host molluscs was greater than 1600 snails/m2 in irrigated perennial lucerne pasture when it was grazed (‘Pasture A’), but was low (<300) in non-irrigated perennial pasture (‘Pasture B’) and non-irrigated f..