Hi Winston,
Thanks for your question.
Coughing can be a sign of many illnesses. This includes things like respiratory tract infections (bacteria, viruses, fungi, parasites), heart disease, tracheal disease, and tumours. Since the coughing has lasted more than a month, I would recommend looking into this further. Uncomplicated, transient infections or illnesses (such as “kennel cough” or infectious tracheobronchitis) should not last more than a week or two. Consider talking with your vet about next steps, such as chest x-rays, to have a look at the lungs and other structures that could be involved.
I hope this is helpful. Best of luck!
Dr. Kim Hester