Should I tell my boss I'm pregnant?

So I'm an animal control officer, and my job is very physical, chasing dogs, catching aggressive dogs, lifting 100 lb dogs into a truck, I also work with cats and I know we aren't supposed to be near their waste but I constantly have to clean out my truck where they poop and sometimes they will just relieve themselves on me. I also worry about dogs ramming into my stomach or getting bit. A fellow officer got attacked a couple weeks ago a huge bite to her hip. I want to tell them but I am only around 8 weeks pregnant. So should I wait until 12 Weeks or should I tell him now?