How to prevent pigs from screaming like pigs when killing pigs?

Do you know the beheading knife used in the execution ground on TV? It's the kind that hangs with a rope, then puts the rope directly when cutting, and the big axe falls directly and beheads. You put the pig there to fix its head and come straight down across the board. Pigs can't bark, blood will spray everywhere, but you just want pigs not to bark!