When you trim as many nails as a dog groomer does, then seeing a little blood during nail clipping is nothing to be too worried about. It can happen quite regularly and we know how to handle the situation.
However as a dog owner, it can be quite scary when you see your beloved pooch with blood on it's paws. Dog's have a small blood vessel called 'quick' in their nails. If you trim the nails a little bit too short then this will start to bleed.
So why is it that the quick can become cut during nail clipping??? Well, when you are with a dog with black nails, it is very hard to estimate exactly where the quick ends. In dogs with clear nails, it is easy to see the quick and to know exactly where to clip. Due to this reason, black nails are a lot harder to clip that clear nails and they are usually the ones that end up bleeding.
As well as that, the quick can be shorter and longer in certain dogs. All we can do is estimate where to cut the nail based on experience. Most of the time dogs with nails that have been allowed to grow for a while and are very long will in turn have a much longer quick (as in, it goes a lot further down into the nail). Dogs that have quite short nails also tend to have a shorter quick.
So the next time you experience nail bleeding after your dog's nails have been trimmed, don't be alarmed. If you are clipping your own dogs nails at home, invest in some clotting powder (like Trimmex) which is readily available in shops.