Grass-cracks or something worse? Cracked hooves in horses explained

better. In addition to treating the defect itself removal or resolution of the underlying cause is essential both to aid healing and to prevent recurrence. 
In the first instance the hoof should be examined by your vet or farrier 
They will assess the depth of the crack and to ascertain if any sensitive structures have been affected. This will include walking the horse or using hoof testers to check for pain or lameness the presence of which may indicate a more serious condition. Your vet or farrier will also clean and debride the crack to remove any contamination. This is often followed by corrective farriery to balance the foot. A shoe may be needed to stabilise the foot and prevent the crack worsening. In some cases a clip or groove above the crack is used to stop it advancing upwards towards the coronary band. Your farrier may also remove some hoof wall at the sole below the crack to reduce any pressure on the crack which may drive the sides apart. 
Severe sand cracks may need to be stabilised with materials such as fibreglass or acrylic
Some farriers will use wire or metal plates to achieve this. The method used will depend on the shape of the hoof the depth of the crack and your farriers preference. It is important to remember that the treatment does not stop with stabilisation of the hoof since these cases will need frequent visits from the farrier to ensure that the foot remains balanced and stable with minor adjustments made if necessary. 
As mentioned earlier it takes on average 912 months for the hoof wall to grow from the coronary band at the top to the sole at the bottom so it will take a long time as well as regular farriery and a lot of patience for the fissure to disappear. 
Prevention
Whilst some horses are more prone to cracks than others the importance of hoof care cannot be emphasised enough. Feet should be checked at least once daily to monitor for early signs of damage. In winter this does mean hosing off any mud to inspect the feet. 
An area of hard ground to stand on while sometimes difficult to find is hugely beneficial in providing good hoof care. Horses that are kept on deep litter or in muddy conditions are more prone to developing diseases such as thrush or white line disease and