Do you feel the effect of Karma when you are just a consumer; for example, if you eat meat, do you get the effect of killing that animal?

Yes. You are causing the fate of that animal by creating demand for the meat. So you are also part of a chain that will have to suffer the consequences of that killing. For example, if the head of the Country orders troops to war, a soldier who kills people suffers the consequences but all the people involved in the chain of command all the way to the head of the country suffer the consequences of that action.