Heat

Question
I am a first time Chocolate Lab owner and my female 22 month old has never
had a visible heat cycle.  I asked the vet if that was normal and they said she
could be having "silent heat" for the first two years.  Well, two years is nearly
here and she still has never been in heat that I know of.  Is this normal?

Answer
Not really.  I can't say how often it does happen.  I would really talk to the vet about having her spayed.  There is some debate about mixed results on cancer when spayed at 6 months, but no doubt it reduces cancer when done later.  Even if you can't tell she is in heat, the males in the neighborhood can.  You have no warning about a possible accidental breeding and an unwanted litter or worse.