I do not know what that is, but if it is the content of a bowel, that is a bad butcher. A proper butcher cuts out very carefully the heart, lungs, stomach and intestines of the carcass. And stores these for examination by a vet. At least that is what quality butchers do. When the intestines are cut open, the proper procedure is to not wash or wipe away the contamination (shit) of the carcass, but cut away a large part of the meat surrounding the contaminated spot. This is done, because the intestines carry bacteria that will be spread over the carcass when washed or wiped away.
The heart and lungs are saved to be examined. This way, the vet can see if the animal had a bacteria or virus infection when cutting open the heart and examining for example the heart valves.
Unfortunately, since the meat industry is big business and penny pinching has been done to the max, the proper procedures are not always done on every carcass and some not even at all.
EDIT:
Forgot the intestines and other organs. These are cleaned i guess and grinded for other purposes or to eat such as baked liver.
That is a "short loin", it's where T-bone and porterhouse are cut from. If it's removed from the bone it's the tenderloin and strip-loin (or NY strip, KC strip, ect). This animal had cancer, that is the pus and discharge. I've seen it in top sirloin butts before but never in a short loin, we also have no idea if that photo has been touched-up or not. The large Co's that pack 99% of all the meat use a person to do one part of the operation. One guy will be on a vertical-moving platform and cut the carcass in half and from there all the primal cuts are broken down with a person trained to do one job in assembly-line fashion.