Limb and Foot Physiology

inside structure of cow's foot

The skeletal structure of the cow's foot and lower leg is composed of several bones; the shin bone, the long pastern bone and the short pastern bone. The pedal boneis the major bone in each claw, providing the structural framework for the general shape of the claw and is an important part of the cow's physiology in terms of good mobility.

The bones have a very important function in bearing the significant weight of the cows and transferring it to the foot. This explains the importance of strong legs and feet for the well-being and productivity of dairy cattle.

The pedal bone is suspended by a thin layer of laminar corium on the abaxial wall and over the front of the hoof, which contains nerves and carries blood to the tissues within the hoof and also carries essential nutrients for hoof formation. The pedal bone is separated from the horn only by the corium, which is very sensitive - equivalent to the quick of the human fingernail - and so is painful if damaged.

The two major tendons in the foot are the extensor tendon, which extends the joints of the leg and helps pull the leg forwards, and the deep flexor tendon - attached to the rear of the pedal bone - which pulls the leg back, flexes the foot and isimportant for mobility and flexible foot movement. The overall function of these tendons is to allow the leg to bend, one end being attached to the muscle and one to the bone. Pedal joint injuries often occur when the deep flexor tendon becomes detached from the pedal bone, resulting in the claw turning up.

As the cow walks, there is limited movement of the pedal bone at the toe; movement is much greater towards the rear of the heel and inner hoof wall where the bone is not anchored. Thenavicular bonefacilitates movement of the tendon where it changes direction within the heel bulb.

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