Individual Cow Guidelines
1. Understand normal foot anatomy to treat and control lameness more effectively
- hooves are made of protein that softens with moisture
- on the outside: the wall, the sole and the heels
- on the inside: the corium and the pedal bone
- hoof design makes it prone to injury in adverse environments
Understanding a normal cow's foot is very important:
- for effective treatment of hoof disorders. (If you had a sore foot, you wouldn't go to a doctor or podiatrist if they didn't know how a normal foot functioned.)
- for consideration of strategies to control and prevent lameness.
1.1 Understand that the claws are made of a hard protein that softens in moisture
The two claws of a cow's foot are made of hard protein called keratin. It gives the claws their toughness, and protects the cow's foot from daily wear and tear.
The protein of keratin can absorb water. This is important because if hooves are continually wet, the keratin becomes softer, and more easily damaged. For this reason, wetness and moisture can contribute to lameness. Dairy cows living in high rainfall areas, or under intensive conditions such as calving pads and feedlots, can have continually wet and soft hooves.
On the other hand, if hooves are continually dry, the keratin becomes very hard, brittle and can crack more easily.
1.2 Recognise the three main parts of the hoof
- The hoof seen from the front or the side view is called the wall.
- The hoof that you see from the rear is divided into two bulbs or heels, one for each claw. The bulbs or heels are covered in thin skin above the ground, and much thicker hoof material where they contact the ground.
- Lastly, under the foot is the sole. A cow bears most of her weight on the wall where it contacts the ground, and the heel, and usually bears very little weight on her soles. Check the hoofprint of a cow made by wet hooves on a dry surface to confirm this fact.
The sole is about 5 mm or ¼ of an inch thick, and is normally concave when viewed from below. Despite the fact that it bears little weight, it can still be worn away. For example, if the ground is particularly abrasive, or if the sole is turned or twisted on the ground too frequently, or if cows are walking long distances, the wall of the hoof wears away, and the sole of the hoof starts to bear more of the weight of the cow. The hoof material or keratin is scraped off to the point where the sole is thinned or worn out. Thin soles are more liable to injury or puncture through to the underlying soft tissue.
Soles can also be too thick (especially in older cows with elongated claws). Then the cow bears too much weight on the sole instead of the heel and wall, and this can cause bruising and pressure ulcers.
- The junction between the normal skin above, and the wall and heels beneath is called the coronet. The wall grows down from the coronet at ½ to ¾ cm per month, or 8 cm per year.
- The junction between the wall of the hoof and the sole is joined by a specialised cementing material, and is called the white line. This is a potential area of weakness of the hoof, and is the area affected by white line disease.
1.3 Gain an understanding of the internal structure of a cow's foot.
- Just beneath the hoof is the area responsible for continually growing new keratin â€“ the corium. Fresh keratin is constantly needed to replace hoof material which wears out with daily use. The corium is very rich in blood vessels that supply nutrients required for hoof growth. (Inflammation of this area is called laminitis.)
- It is also rich in nerves that sense the ground surface as a cow walks, and sense pain when the hoof is damaged or diseased.
- Enclosed in a protective layer of hoof, and nourished by blood vessels of the corium is the pedal bone. Strands of strong fibres join the hoof and sensitive hoof-growth area directly to the pedal bone. There is also a cushion of elastic fibres and fat between the pedal bone and the heels. It protects the sensitive corium from downward pressure of the pedal bone and upward pressure of uneven surfaces on the sole as the cow walks, absorbing concussion.
- The pedal bone connects with other small bones in the foot. Joints between these bones give the foot flexibility. Tendons link the bones to muscles up the leg, allowing the foot to move forwards and backwards in normal movement.
- Understanding this structure is important for managers wishing to better control lameness. As an example, imagine a cow walking on a sharp stone. The pedal bone presses down with say 140 kilograms (or more) of body weight above it. The sole bends upwards because of the stone under it. This upward flexing is more pronounced if the sole is soft due to excess moisture. The corium is squeezed â€œbetween a rock and a hard placeâ€ and damaged. A bruise develops in the corium, and because of the nerves in the area, pain, lameness and consequent losses result. Knowledge of this sequence leading to lameness clarifies the importance of such issues as selection of track surfaces, track maintenance and cow handling.