What really causes footrot in sheep: A national cohort study of the serological diversity of Dichelobacter nodosus in sheep in sickness and in health

Project lead: Professor Laura Green

Project contacts:

• Naomi Prosser (University of Warwick)
• Laura Green (University of Birmingham)

The prevalence of lameness in sheep in England fell from a geometric mean of 5.4% in 2004 to 3.5% in 2013. This reduction was associated with changes in the management of lameness. The Farm Animal Welfare Council has set a target for the prevalence of lameness to be less than 2% by 2021 therefore further improvements to the control and management of lameness need to be achieved in order to achieve that target.

Most lameness is due to footrot (both interdigital dermatitis and severe footrot) which is endemic in the UK and present in almost every flock. There are ten serogroups of Dichelobacter nodosus (the causal agent of footrot) and in the UK there is one licensed multivalent vaccine targeted at nine of the serogroups. It has limited efficacy, possibly due to antigenic competition between serogroups, and reduces lameness by approximately 20%. Published research has demonstrated that autogenous mono/bivalent vaccines are more effective at control. Previous research into the diversity of the serogroups in the UK have investigated no more than 40 flocks.

This project aims to update our estimate of the prevalence of lameness in ewes in England and to identify the main risk factors for the lameness. It also aims to investigate the serological diversity of D. nodosus which may help improve our approach to control using vaccination.

This project is being conducted in conjunction with the University of Warwick.