Evaluation of ultrasonography for measuring solar soft tissue thickness as a predictor of sole ulcer formation in Holstein–Friesian dairy cows

The aim of this research was to investigate the correlation between the thickness of solar soft tissue (SST; i.e. the corium and subcutaneous tissue) in early lactation and sole ulcer formation in late lactation. Fifty Holstein–Friesian cows were examined three times: (1) 30days after calving (locomotion scoring, trimming, claw examination, measurement of SST); (2) 70days after calving (locomotion scoring); and (3) 180days after calving (locomotion scoring, trimming, claw examination). SST thickness was measured using an 8MHz linear probe, at two points (SST1 below the apex of the pedal bone, and SST2 below the flexor tubercle). Mean values for SST1 and SST2 were 3.26±0.43mm and 4.35±0.46mm, respectively; the two measures were positively correlated (r=0.95, P