A properly sized and positioned hoof block can do wonders in helping cows recover from hoof lesions and trauma. On the other hand, improperly sized and positioned blocks can create more problems than they solve and prolong lameness and cow suffering.
At first glance, it might appear that hoof blocks on the healthy claw make the cow uncomfortable and even off-balance. But years of hoof block use show that when properly used, they can bring healing and comfort to a lame animal.
“Blocks improve healing by removing the pressure from the affected foot,” says Gerard Cramer, a veterinarian and hoof care specialist at the University of Minnesota. “This reduced pressure allows the wound to heal by reducing tension that pulls cells apart, thereby enabling horn cells to grow and close the sole defect.”
Proper sizing is critical, because a hoof block that is too short can cause potential harm by not providing full support to the entire healthy claw. “An appropriately sized block extends beyond the weight-bearing surface of the heel. In most situations, this means the appropriate block length is between 5 ¼ and 6” (13-16 cm),” Cramer says.
The block should extend past the weight-bearing surface of the heel because this will reduce pressure on the soft heel horn when the heel strikes the floor while the cow is walking. Extension of the block will also reduce the risk of the block itself causing or inducing hemorrhages and ulcers, he says.
Blocks are too long if they extend past the non-weight bearing part of the heel to the level of the dewclaws.
“Correct position of the block involves ensuring the block is applied at a 90°angle to the bones of the leg,” Cramer says. Doing so ensures that weight bearing is correctly positioned on the claw with the hoof block and is not transferred to the outside wall of the diseased hoof.
Cramer notes that there is a tendency for blocks to wear down over time towards the inside of the healthy claw. To counteract this, apply the blocks at an angle less than 90°(sloped up towards the inside of the hoof). Done this way, blocks that do shift will still not shift weight on the diseased claw.
To allow sufficient time to pass for healing to occur, blocks need to stay in place for four to six weeks. A block left on longer can cause damage to the unaffected claw due to excessive weight bearing, says Cramer. So farmers must schedule a follow-evaluation in four to six weeks after a block is applied to check on the healing process and ensure the block size and position are still correct.
“Cows that are not healing properly can be retreated at the time of evaluation. Cows that have healed can have their blocks removed. In both scenarios, the re-evaluation develops a process that reduces the chance of developing chronic lesions,” says Cramer.