Why is my older pet coughing? There can be several reasons why an older pet could be coughing, such as heart disease or a respiratory infection. Any development of a cough should be assessed by a veterinarian to determine the cause and necessary diagnostics/treatments. (p) Previous What does it mean when my pet is shaking uncontrollably? View Post Next (n) What does it mean if my puppy's belly is swollen? View Post