Are the cattle mutilations seen as ritual killings and occurring around the world, really done by Reptilian extraterrestrials? Do they drink the blood and eat select parts, like the tongue, brain, or reproductive organs, which are often missing?

Your question contains the answers and is accurate in all respects. Reptilian extraterrestrials are physical beings, and being predators they enjoy fresh meat of other species including humans. So it is fortunate that you are asking about a phenomenon involving only livestock. They are more discrete in disposing of human remains when that happens, including infants who are taken and sometimes devoured on the whims of these savage beings. They operate with impunity because the other extraterrestrial races joined with them in the Extraterrestrial Alliance do not care what they do and are themselves savage predators. So the reason the remains appear to be from killing in a ritual fashion is because of the dissections of specific anatomic locations that seem quite precise and purposeful, and the fact that select missing organs are noted as well as blood being drained from the carcass. The particular choice of tissues removed is truly what is considered a delicacy by particular Reptilian beings who are out on missions and in need of nourishment. They are simply taking what they want among animal livestock and leaving the remains behind quite brazenly. True to form, this has remained an ongoing mystery that is often given prosaic explanations assumed to be simply an unusual selective devouring by animal predators of a dead cow, or the actions of humans conducting some kind of bizarre ritual that is inexplicable, so such accounts get little attention in the media.