You can begin feeding your baby yogurt as early as 6 months of age which is also when most babies are eating other baby foods.
As long as the baby has no dairy allergies they can eat Yogurt at 6 months of age and above and the yogurt will be healthy for them as well.
Babies can eat yogurt as soon as they are eating baby foods.
Once you start the baby on solid foods they can begin eating Yogurt and other soft foods and then as they get their teeth in they can eat other foods.
Still though if you feed your baby things such as hot dogs or other meats cut the meat and hot dogs up in small pieces so that the baby doesn't choke on the meat or hot dogs.