My mechanisms for pain and suffering really aren't any different from those of a dog, a pig, a cat, or a rat.
The mechanism is the same, but the effect is very different. Other animals do not exhibit the anxiety about expecting or experiencing pain that humans do. While that does not justify putting animals in unnecessary pain, it does mean we should be careful not to anthropomorphize our reactions to pain (or anything else, for that matter) onto animals.
>Other animals do not exhibit the anxiety about expecting or experiencing pain that humans do.
What are you basing this on? If a mammal is exposed to pain, any stimulus similar to that initial cause of pain will cause anxiety and fear, just like in humans. They may not understand the cause-effect relationship of the stimulus as clearly as humans, but they certainly have the ability to expect and fear unpleasant stimuli.
The mechanism is the same, but the effect is very different. Other animals do not exhibit the anxiety about expecting or experiencing pain that humans do. While that does not justify putting animals in unnecessary pain, it does mean we should be careful not to anthropomorphize our reactions to pain (or anything else, for that matter) onto animals.