Loosing hair behind its collar.

Question
I bought my cat a collar but have just noticed that he has lost all of his hair around his neck, benhind the collar - it's almost like it's been perfectly shaved all round in a ring.

Answer
Emma,

What kind of collar?  Normally collars and cats are not good together for a variety of reasons.  I would strongly suggest not using the collar on your cat.

If you are using a flea collar, there are much better and safer ways of controlling fleas (e.g. Frontline).  Some of the flea collars have caused severe reactions in cats.

Best regards... Norm.