Sorry about your loss, man. .... Brave with the autopsy ... i don't think i could have done it (did not do it on my dead ray) - but it is important for further study
wow im so sorry for your loss! her bum looked really inflamed and swollen outward-thats probably something there-i would have dissected her bum too to see if something was in there, or if it was inflammed all the way inside. she was quite red underneath on the belly, but like others have said-she had been dead for a while and her blood would have pooled in the bottom of her ( in humans we call that "Dependant lividity"-the blood doesnt flow, leaks out of the capillaries and veins and settles on the part the person is lying on).
Her liver has that spot-it looks like a blood clot-but youd have to ask a vet if that is pre or post mordem-it could have occurred after death..
Either way, it sucks-and im sorry you lost her-she was a beauty!
Nothing out of the ordinary on the inside of the bum bum LOL! I don't know exactly how long she was dead but after 30 minutes in the freezer her whole under belly turned red and her bum bum went back to almost normal. I think she started to bloat and that is what caused it to push out.