Your dog can't tell you when she/he's sick, but she/he can give you clues. You are your best friend's most important health care provider, since you see her/him every day and decide when she/he needs to see the veterinarian. Here are some tips to help you to determine if your dog might be ill:
Does you pet's body temperature feel hot/cold ?
Are the gums color pink, pale pink or different?
How is she/he activity level: same, looks tired...?
Is she/he eating, drinking, urinating normal?
Have you seen any vomit and/or diarrhea?
Have you heard her/him cough and/or sneeze?
Have you noticed an increased in shedding or bald patches?
is she/he reluctant or presenting difficulty in getting up or going up and down stairs?
If you answered yes to any of these questions your pet needs to be seen by a veterinarian. Serious medical conditions start with mild or unapparent medical signs.
Keep in mind in medicine is not only what is done but when. Same medical treatment may not work if waited to long to start it.
Prevention is the best medicine in the world.