IMO, raising an animal solely for the purpose of obtaining its milk, eggs or flesh leads to the obvious conclusion that it's nothing more than a product. I think that to be truly ethical you have to think of something as being on the same level as you - not as a meat/milk/egg machine.
There's also the question of judging when an animal has suitably lived out its life. When is it okay to decide that an animal is ready to become meat? No matter what, you're cutting its life short.
So, in short, no, I wouldn't feel comfortable with that.