I would like to thank my classmate Dr. Gerard Cramer a bovine hoof and lameness expert for his guidance on the topic.

 Vertical (sand) cracks of the hoof have no one single cause.  The most important factors involve the conformation and strength or quality of the hoof.

Abnormal conformation is a risk factor because the stresses and forces acting on the hoof wall are not normal and these cause points of weakness in the hoof.

The strength or quality of the hoof horn is primarily affected by nutrition.  Make sure the herd has adequate levels of copper, zinc, molybdenum, selenium and vitamin E all of which are important in hoof strength.  Where hoof quality can be affected is when levels of copper and zinc are too low, or increased levels of molybdenum and sulphur will cause the copper levels to become artificially low as they bind to the copper and make it unavailable.  Excessive levels of selenium can also be detrimental to the hoof quality.

Animals with a body condition score (BCS) of 4.5-5.0 (on a scale of 1-5) put added stress on the hoof and should have their diet adjusted to decrease their weight.  However, feed changes themselves (significant increase in protein and

starch) can lead to laminitis that will weaken areas in the hoof and increase the chance of a vertical crack.

Treatment

Only treat the ones that are lame.  Hoof testers are needed to rule out any other cause of lameness.  I would call on a hoof trimmer or your vet to deal with the hoof.  They will treat the affected claw according to what debriding needs to be done.  In all cases, a block should be placed on the unaffected claw.

Prognosis

The horn of the hoof grows 5mm/month so healing will take some time.  The prognosis is more favourable of course in a non lame lighter weight animal and is strictly case by case.

Prevention

The best way to prevent vertical cracks is through proper conformation and nutrition.  Select genetics (sires) with good feet and legs and cull animals with poor conformation.

Keep the herd in a good plain of nutrition that includes a properly fed vitamin/mineral premix.  Feed the premix at the recommended levels and draw blood on animals to determine if the blood levels are within range.