Diagnosis and treatment of joint infections in 39 adult sheep

A retrospective study of sheep lameness over three years revealed bacterial infection of a single joint causing severe lameness in 39 adult sheep; 5 cases were presented for veterinary examination within one week of onset of lameness. Diagnosis of a septic joint was based upon findings of severe lameness (defined as intense and extended duration) with thickening of the joint capsule. There was no significant joint effusion. All cases had been unresponsive to antibiotic therapy before referral. A penetration wound was responsible for single cases of sepsis of the stifle, shoulder and fetlock joints; the remaining 36 cases originated from bacteraemia. A potential primary septic focus was identified in six sheep at necropsy; a further six sheep had vegetative endocarditis. Radiography added little additional information except for sheep with infection of a growth plate, and neglected cases where animals had been lame for more than three months. A single treatment success was achieved with joint lavage and arthroscopy from four cases which had been lame for less than one week. All other lame sheep were euthanased for welfare reasons at presentation. Necropsy findings of unresponsive cases were characterised by pronounced synovial membrane proliferation and hyperaemia with fibrous tissue proliferation within the joint capsule and, in neglected cases, erosion of articular cartilage. Most joints contained small amounts of a pannus.