Stiffness and pain in the joints or muscles may affect older pets. Do not take a pet who lays around all of the time on a weekend hike up one of our mountains. Such an event would require some training in the older pet if it is not used to hiking. Heart disease is quite often encountered in aging pets. The most common sign in dogs is a gagging cough as if trying to cough up and swallow something.
Some pets actually produce some white froth coughed out of the lungs.
In the cat with heart disease, a sudden paralysis of the hind limbs can be the result of a blood clot thrown from a diseased heart which lodges in the artery feeding the hind legs. The feet will feel cold and the paws will look pale when compared to the front feet. Heart disease can often be treated successfully and your dog can live out its full life. I raised a dog to be 22 years old with a heart murmur. Consult your veterinarian if your pet has a persistent cough.