Thanks for the link with the remedy suggestion Doganjo, good to have that filed away just in case!
For those who asked about 'what to use and which potency' you should remember that homeopathy is all about treating the individual, not the disease. Every dog will show different symptoms if infected with KC and the individual symptoms should guide you in selecting the remedy. The link above should help in that: it lists a number of remedies that will match a cough that can be dry, or deep, or worse at night, or when lying down, or with flecks of blood, etc... You need to look at your dog and decide what he needs for 'his' KC.
In my understanding the potency is of secondary importance, use whatever is to hand but spend some time trying to choose the correct, i.e. symptom matching remedy. Generally thugh the more acute the symptoms the higher the potency selected - I have been advised to use 30C or 200C as good 'general use' potencies.