In all honesty I could hardly look at this to be able to pin it. This is NOT a one off image, abuse and neglect is common place in the farming of sentient beings. If YOU eat flesh then you are to blame, YOU create the demand. Slaughter houses are places of death and destruction, abuse is rife by twisted callous people who KILL for a living, just because YOU personally do not kill these animals does not mean you are not guilty. Paying someone else to KILL the flesh you eat is wrong.
Tumors are very common in our farm animals flesh, but the flesh is cleaned out on the outside and the meat is still salable. Ask any butcher. There is nothing unusual with purulent tumors in the animal flesh you buy. They cut the tumor off and wash the pus away with a lot of bleach, then after it is cleaned out they sell it to you and you have steak or roast for dinner. Yummy!