I do remember that people like this have studied animal behavior more closely and used it to make the design of slaughterhouses more humane. But interestingly she also observed that animals have the ability to hide pain:
https://www.cpr.org/show-segment/temple-grandin-on-why-slaug...
When a predator sees a group of possible preys, the first thing he does is to observe them to detect the weakest one. Hence the weakest animal has to hide his pain/sickness and pretend to be ok.
In this context, when female mammals give birth, they automatically eat their placenta and lick the blood on the floor: to leave almost no traces that would give clues to predators that birth has taken place (to protect their offspring, in other words)
I always find it surprising people think animals aren’t aware of mortality, their impending death, etc. Spending time with animals it becomes clear, at least in my experiences, that the primary difference between their experience and ours is the ability to communicate it and that life writ large has a very similar existential experience.
But killing a large animal, like a cow, by hand using a knife is hardly "humane" or "unavoidable". The slaughtered animal would experience severe pain and awareness of its situation before it eventually loses consciousness.
But the suffering doesn’t start with the fatal injury and suffering is often less about pain and more about the torment of what’s about to happen. That’s true for people and for animals. IMO that’s the point
Mountain goats have probably slipped and fallen off cliffs, but I doubt they have fear of heights. Interestingly they probably are able to calculate whether a jump is doable or not, but do they doubt themselves? I guess cats and dogs show doubt..
A captive bolt gun costs $200. If you kill your cows with a knife, you must have some kind of problem in your head.
There is no ethical slaughter.