Because of the tremendous terror, physical pain, and moral agony dumb creatures must inevitably go through when faced with their bewilderingly precipitate and harsh death at the hands of humans—an agony they cannot even give voice to in their total helplessness to plead with those who are cutting short their lives—it is better, if possible, to refrain altogether from eating animal flesh. For every piece of meat less that is consumed means in time one animal less will go to the slaughterhouse.
The suffering and unhappiness these dumb beings sustain when being slaughtered can never be easily borne by any sensitive being endowed with a certain capacity for thinking and the power of physical movement, and in whose veins red blood also flows. This, the symbol of passion, indicates a degree of intelligence in animals comparatively greater than in the vegetable kingdom (which has white sap) and relatively nearer to the human one.
Furthermore, as these animals are put to death coldly and often under cruel conditions, their moral agony is all the greater. Every cell in their bodies becomes infused with the sensations of utter hopelessness and anguish of their premature and brutal death.
At such an atrocious moment, these unfortunate creatures become intensely alert and concentrated. The feelings of terror, helplessness, and despair that they go through during these fearful instants—not to mention also the anger and hatred that they bear toward the humans who are slaughtering them—are, in keeping with the violence of these moments, extremely powerful. These final terrible emotions that they take with them when dying inevitably infect their flesh and remain highly active in it, and when consumed by people—especially in the heedless manner in which they generally do so—it is bound to influence their inner state adversely and gradually fill them with sentiments corresponding to those that these ill-fated beings had in them at the time of their death.
Edward Salim Michael – The Law of Attention chap 46