Oral Presentation The Prato Conference on the Pathogenesis of Bacterial Infections of Animals 2016

Preliminary investigation into epidemiology and microbiological analysis of femoral head necrosis in broilers in Australia. (#12)

Dinidu S Wijesurendra 1 , Anthony Chamings 1 , Amir H Noormohammadi 1 , Marc Marenda 1 , Andrew W Stent 1
  1. Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville and Weriibee, VIC, Australia

Lameness is a major economic and welfare issue in commercial broilers and significant proportion of cases are a result of the femoral head necrosis (FHN). FHN is a bacterial osteomyelitis and the pathogenesis of the disease is multifactorial. FHN seems to be a common, sporadic condition in Australia, the epidemiology and causative agents related to the disease has not been closely studied. The aim of the studies described here was to examine the epidemiological factors and microbiological analysis of FHN in broilers in Australia. A retrospective cross sectional study was performed using RSPCA cull data from 18 farms. One model investigated the effects of the time of placement and climatic conditions, while the second model investigated the effects of flocks and shed characteristics, on lameness culls. For the microbiological analysis cull birds were collected from 5 broiler flocks in which gross FHN lesions or significant leg problems had been seen. At post mortem birds were examined grossly for leg, bone lesions or signs of other pathology, swabs were aseptically collected and bone samples were taken for histopathological assessment from the proximal femur and tibiotarsus. The median lameness culls were significantly higher at consecutive summer months, December and January. However, there was no significant relationship between monthly average temperature or total rainfall and median lameness culls for flocks placed that month. The median percentage lameness culls were significantly higher in sheds with curtain walls than sheds with solid walls while relationship between male to female ratio, stocking density, age of farm and the lameness culls was not significant. E. coli and Staphylococcus spp were the predominant bacteria isolated from the joints and investigations to date revealed E. coli was more commonly isolated from younger Australian broiler flocks, while the isolation rates of Staphylococcus increased as the flock aged.