A study of the biomechanical factors involved in foot-floor interactions in Friesian cattle with reference to aspects of lameness
The forces and pressures applied to the hooves of Friesian cattle during gait were investigated using a combined force plate and pedobaroscope. Studies included those concerned with changes in loads and pressure with increasing live weight, flooring surface, stages of pregnancy and differences in gait with lameness. The forefeet carried significantly greater loads (i.e. equivalent to 60 per cent of body weight) than the hind feet (i.e. equivalent to 50 per of body weight), but no difference in load was observed between contralateral limbs. In most cases no significant difference was observed in contact area between feet. However with increasing live weight hoof-ground contact area increased at a rate exceeding that expected from allometry. The obtained relationship between area (A) and live weight (m) was A = 10.96 m0.96. Pressure did not increase significantly with live weight. No significant decrease in contact area or increase in pressure was observed with a simulated slot, of 12 mm width, in the floor. During pregnancy the load distribution did not change significantly, though pressures were observed to increase slightly on all feet in the pre-partum period. The vertical ground reaction and horizontal fore and aft force-time curves of lame cows were different to those obtained from non-lame cows. The force-time curves of the non-lame limbs of the lame cattle were also modified. It was concluded that the heel region was compressed of the inter-digital space increased to increase the solear ground contact with increasing load, to reduce applied pressure. This would reduce the risk of pressure-induced injury and lameness. The load distribution during pregnancy did not explain the higher incidence of lameness on the hind feet at this time and other factors may be implicated. Changes in applied forces on limbs with lameness may act to alleviate pain. The forces applied to the non-lame limbs may compensate for the change in load on the lame foot or act to further alleviate pain. Further work is suggested to relate the risk of injury and lameness on different floor types to the applied loads and pressures.