what kind of dog have you got,breed I mean?Many years ago I had a dog,which I got as a pup.It was a mongrel of the terrier type best wee dog I could have wished for,she used to go into the dookit with me and one one occasion,she went out of it with a squab in her mouth,unharmed,where i found her on the grass licking it.Anyway I digress;on taking her to the vet for her first injection,he almost laughed;mongrels have an immunity to all kinds of diseases,not worth spending your money on ,he said,so she got one injection and never again.I had her for fourteen years and finally had to say goodbye to her because of arthritis.A day I'll never forget. Maybe you have a pedigree dog,so this won't apply.I think it cost me £15 at the time but that was 1986