In general, the fewer baths, the better. Are you rinsing well and using a conditioner? If weekly baths don't seem to be causing a problem, ''if it ain't broke, don't fix it''.
A healthy Lab should be able to go indefinitely without a bath. My Aster hasn't had a bath since she came back to live with us 3 years ago. She is brushed regularly, and gets occasional swims in the river.
Are the walks off lead giving her a chance to roll in smelly stuff? If so, that could be the problem. If you don't keep their relief area cleaned up, some dogs will roll in their own feces.
She should be back at the vet at 6 months for shots and spaying. If the smell problem seems to be her and not what she rolls in, talk to the vet about it. Even if she is doing OK now, as she ages, the weekly baths eventually could be too much for her skin.
In the winter, a Lab will grow a second woolly under coat if exposed to the cold very much, typically sleeping outside or left in a fenced yard all day. Labs that are house dogs don't develop the second coat although they still have plenty of hair to shed in the spring.
