I'm sorry but i think you are missing the point. I am not arguing about the specific numbers you put into your model, but the entire premise.
You are mixing highly subjective values with quantifiable values into a mathematical formula and are expecting a meaningful output. This does not make any sense. The VSL is it self very subjective. It is a tool designed to estimate what we are willing to pay to save a life. Mixing in the EQ and slaughter age is nonsensical and does not yield any sort of meaningful number.
As for the cruelty calculation this is nonsense as well. The original number from the study sounds like it was based on what people where actually paying in dollars in order to reduce cruelty. I don't know how it was calculated so i can't comment on that. However, it is clearly different from what you are doing, by multiplying brainsize with age. This doesn't yield any sort of meaningful result. your might as well multiply the height by the eye color. What is it that you expect that number will tell you?
If you wan't to create a tool for people to use based on VSL, just have people estimate how they value a human life in relation with a cow life. I.e. how many cows should you save in order to justify the loss of a human life. This is essentially what your doing with EQ/slaughter age calculation. This way people can evaluate for them selves what the "morality" cost is for them.
E.g. someone who doesn't value a cows life at all will get zero dollars in "value of life" and someone who values it at 1/50 like you mention will get a similar number to you. This approach is not flawless, but it is every bit as accurate as yours, actually makes a bit of sense and might actually be useful for people to calculate their own moral in dollars like what seems to be your aim.
I would agree with you that I am dealing with several highly subjective values. Like I said before, this is just a start. Since I made that video, I have been looking at a possible range of values for valuing life. This of course would start with the use of existing VSL for humans. I will also need to investigate other ways of determining intelligence of animals. It would be good if I could establish a degree of sensitivity to pain for each species. I think investigating a relationship between intelligence and, physical and mental suffering might be a better path to take; this would still be tricky as there are many other factors that are likely to effect pain tolerance which are unique to each species. So to cut a long story short, I would expect a range of values for the value of an animal's life. I might even be able to come up with a distribution of results, wouldn't that be cool.
The original study looked at just the costs of improving conditions on farms to reduce animal suffering and discomfort from existing practices. This approach only captures a very small amount of the costs of cruelty.
What you propose regarding people estimating how they value a human life in relation to a cow's life could produce absolutely any value based on opinion. I think this is very dangerous. What if, like you said, people valued a cow's life at zero. It is better to keep human opinion out of this. Even willingness-to-pay data is based on people's response to various questions and scenarios rather than a direct question on how they value another person's life or their own life for that matter. Brain weight and body weight is not influenced by human opinion and neither is life expectancy. This way we can mostly (there is still my own bias in regards to the selection of criteria to determine the adjusted value of an animal's life, providing a distribution of results should greatly reduce this) remove human bias.
Thank you for the interesting discussion.