Why choose a soft surface?

The reason why cows choose an elastic surface can be explained by the anatomic conditions and the biomechanics of locomotion. Walking is the result of shifting the balance point forward by a push of the hind legs. The front leg is then moved forward to balance the push of the hind leg. To be able to do this smoothly a cow lacks a collarbone, but the front legs are attached to the body through a brawny mounting with the shoulder blade. A similar shock absorbing construction for the hind legs would mean a needless loss of power. That is why the hindquarters have a fixed attachment to the body skeleton.

The difference in anatomy between front and hind legs has a significant impact on the load the claws have to deal with as intermediate between body and surface. The absence of a shock absorbing construction in the hind legs implies a stronger burden on the legs and claws. This physical difference also explains the findings in the field where most of the time the claws of the hind legs cause locomotion problems.

An additional effect to deal with is the biomechanical differences between the inner and outer claw. The slightly unsteady walk of a cow results in an extra pressure load on the outer claw when moving the body weight from one leg to the other. On a hard floor the claw cannot sink into the surface and will carry most of the weight. The distribution of weight within and between the claws change, especially on the rear feet and legs. The outer back hoof carries 60% of the weight in a mature cow. Outside claws continuously correct changing weight loads. The change in weight distribution is believed to be the cause of rapid horn growth and high incidence of outside claw disorders.

Step Length 

A soft floor changes animal behaviour in the free stall, especially locomotion. Research at the University of Hohonheim in Germany showed a significant higher activity of the cows. Per hour they took on average 30 more steps than on hard flooring, which cumulates to around an extra 1000 metres per day.

Comparing step length on pasture and on concrete slats with and without rubber coatings also shows significant differences. On pasture the average step length is 80 cm. Here the cow with her hind claw steps into the imprint of the forefoot. This way the cow can transport the visual controlled step of the fore foot onto the hind claw. The cow also takes maximum advantage of a layer of very soft shock absorbing horn in the ball segment of the claw.

In the passageways of today's housing systems long swinging steps provide a higher risk of slipping. Animals try to avoid this by adjusting their step length to an average of 58 cm. When concrete slats are covered with a rubber lining, step length increases to an average of 78 cm, which nears the length of the steps when walking on pasture and can be seen as an expression of improved walking security.

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