But most importantly, when I do eat meat, I choose meat that has nothing to do with the awful practices of the factory farming industry. - Katherine Marko, thealternativedaily.com
2015: Being vegetarian is a personal choice. It should be decided not because killing is wrong. Killing plants too is wrong. Its a matter of what your priorities are. Avoiding rajasic and tamasic food is only important for people who are trying to increase their sattwa.
But since you must kill to eat, and rob the young of its mother's milk to quench your thirst, let it then be an act of worship,
And let your board stand an altar on which the pure and the innocent of forest and plain are sacrificed for that which is purer and still more innocent in many.
When you kill a beast say to him in your heart,
"By the same power that slays you, I too am slain; and I too shall be consumed. For the law that delivered you into my hand shall deliver me into a mightier hand.
- Kahlil Gibran on Eating and Drinking in The Prophet
Which is the same thing being said on stackexchange (see link above) - you must offer it up as a sacrifice to your God. So if you do the same with animals, then its OK.
So again, coming back to priorities:
But the disciples of the saints have as their chief aim and effort in life to rise above the animal plane and to unfold their spiritual powers. Hence they must not eat that which will pull them down to the animal level.
- karma and the vegetable diet
That being said, by rearing animals, we are creating opportunities for their souls to take birth and evolve. So in a way, we are speeding up the evolutionary process. So, its a dicey question and the truth is, look at the pros and cons, and let your heart decide.