Physical, biochemical and cellular comparison of synovial fluid from the distal interphalangeal joint and distal sesamoid bursa in normal and abnormal hooves of cattle

A common area of lameness in cattle is the digital region, especially the distal sesamoid bursa (DSB) and distal interphalangeal joint (DIPJ). Physical, biochemical and cellular evaluations of the synovial fluid of the DSB and DIPJ were compared in normal and abnormal hooves in cattle. Synovial fluid from the DIPJ and DSB from 22 normal (11 hind limb and 11 forelimb) and 27 abnormal (16 hind limb and 11 forelimb) hooves of both sexes of Holstein cows were collected. Clinical observation of animal gait before slaughtering, grass evaluation and radiographic examination of the hoof was the basis for allocation to either the normal or abnormal group. Physical characteristics which were evaluated included the quality of mucin clot, gross appearance and viscosity. Total nucleated cell counts, differential cell counts, protein and glucose concentrations and the activities of AST, ALT, LDH and ALP were measured by validated standard methods. The mucin clot quality was graded as predominantly good (86%) in normal samples, as opposed to moderate (68.5%) in the abnormal samples. The viscosity of the majority of normal specimens (81.6%) was good, and more than 70% of the abnormal specimens had a moderate grade. Total nucleated cell counts of the synovial fluid from the normal group were 59.45±4.25 and 55.93±3.89 cells/μl (mean ± SD) in DSB and DIPJ, respectively, compared with 92.18± 4.76 and 93.06±4.75 cells/μl in the abnormal group. The glucose concentration of normal synovial fluid from the DSB and DIPJ were 34.25±0.71 and 32.55±0.52 mg/dl, respectively, and showed no significant difference between these two samples. The results reveal that the enzyme activity of the abnormal synovial fluid from the DSB and DIPJ significantly increased. Also, there were no significant differences between the mean concentrations of total protein in the normal and abnormal synovial fluid specimens. Despite the non-significant differences of some cellular and biochemical parameters of synovial fluid between the DSB and the DIPJ, the differences of these variables in normal and abnormal hooves may be beneficial for the diagnosis of healthy and abnormal synovial fluid.