Claw lesions in dairy cattle: development of sole and white line haemorrhages during the first lactation.

The development of claw haemorrhages was monitored in first-calving dairy heifers from 4 weeks before calving to 32 weeks after calving. Before calving, lesions were few but the number, extent and severity of claw haemorrhages increased following simultaneous calving and housing. Lesions were most severe in the white line at 9 weeks, and in the sole at 14 weeks, but recovery began while the animals were still housed. That the increase in white line lesions after calving, and the subsequent recovery preceded that of the sole, suggests that the pathogenesis of the lesions may differ in these two anatomical regions. It is proposed that an initial insult to the corium primarily affects the laminar region and that corium damage increases with the resulting alteration in the physical forces on the sole.