Leave it alone
Since your sample of cows standing is not a random sample within the entire population of cows, it does not fairly represent the entire population of cows. Therefore, the degree to which you can determine reliability or a confidence level in your statistical analysis is limited. Have you calculated the standard deviation? Further, I am not sure you have performed regression analysis to determine the actual correlation between fishing results and the cow standing factor.
I would recommend you leave it as it is. But as Forrest says, "stupid is as stupid does."
Thanks for your great and fun fishing reports!
I don't live just to fish, but I want to fish just as long as I live.