I’d like to have a chat about claw blocks this month. There are a variety of options out there and whilst they all do the same thing, they all have their pro’s and con’s. The principle of the block is to glue it to the sole of the healthy claw. This way, the weight of the cow is being relieved from the sore claw giving it the rest it needs to heal. If you are in doubt as to whether a particular cow needs a block or not, you should put one on. It is only when you are sure she doesn’t need a block that you can decide not to use one – remember a claw block is always cheaper than a lame cow. A cow that has a lesion in the claw will walk much better when a block has been fitted because the pain has been reduced significantly. Claw blocks provide lifelines for many cows that otherwise would have ended up at the works.
The thing with claw blocks is that they need to be placed correctly on the claw. All the weight that was spread out over the two claws is now only going on the claw with the block attached. This means that the block needs to be fitted flat, in line with the interdigital space and far enough back on the heel of the claw as this ensures that the claw is still supported properly. Imagine what it would be like if the sole of your shoe was attached all wonky.
Preparation of the claw is key to getting a good adhesion regardless of what type of block you use. The claw needs to be clean and dry, but dry is more important than clean. We don’t recommend the use of methylated spirits, just clean the claw with your angle grinder and/or knife and make sure you keep water away from the claw throughout the whole trimming process. Water gets absorbed into the claw very easily which doesn’t help the glue. A block should normally stay on for 4-6 weeks. Any longer and you will risk lameness on the healthy claw because of the constant overloading, which means that the block should be taken off after 6 weeks if it hasn’t come off by itself. I would recommend that cows are kept close to the shed until the block is not required anymore, if possible.
The different options for claw blocks include: the shoe type blocks, wooden block and rubber/polyurethane block.
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Shoe type block
These blocks will stay on the claw for a decent amount of time – often for too long, and they are not particularly easy to remove. They can also be too small for some cows. If the block is sitting too far forward on the claw, then the heel is not supported properly. This can force the toe upwards which will put a lot of strain on the deeper flexor tendon. The Demotec Easy bloc design does overcome this problem with the block part of the shoe set back from the toe, and the shoe part is quite flexible allowing a better fit on different sized hooves.
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Wooden blocks
These blocks are glued to the claw with either a PU glue or a super-glue. It is even more important with these blocks that the claw is prepared properly for the block as there is less contact area with the claw. The big advantage of the wooden blocks over the shoe-type blocks is that you can place them better on the claw. It doesn’t matter if the claw sticks over the front of the block as long as the heel is flush with the block. If cows are put back with the main herd after being blocked, then the woodblock may wear too fast if long distances are being walked. These are usually the most cost-effective option.
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Rubber/polyurethane blocks
These work the same as wooden ones and the same glue can be used. Rubber blocks are harder wearing than wooden blocks which can be useful if the lame cows can not be kept close to the shed for whatever reason. The disadvantages are that they need to be taken off more often than wooden blocks (and are more difficult to remove), and they are not very environment-friendly.
