Reviewed by Dr. Becker

And about 80% will show symptoms. Fortunately, the risk for serious disease is quite low except for these special groups. But watch out for this standard advice that doesn't work, and can seriously impair your pet's immune system. They'll pull out all the stops to drag you in.

It can strike dogs as young as age 6. By age 11, it affects 50% of dogs and by age 15, 68%. What's more, if you recognize the signs you can set the stage to help them ease through their senior and geriatric years with more purpose and companionship, and less pain.

There's no one straight answer to this as it can depend upon the breed and their size. Here's what to expect as your little fluff ball moves through each stage of puppyhood and beyond.

The average dog has about 15,000 hairs per square inch — 15 times the density of human hair. No wonder shedding is a problem (even in so-called hypoallergenic breeds). Many factors affect the amount of shedding. There are steps you can take, but please avoid this bad advice.