Prohibition of Eating Neveilah or Treifah
It is forbidden to eat the meat of an animal that died by itself or was not slaughtered in accordance to the laws of Shechitah (kosher slaughter). Such an animal is called a neveilah (נבילה). Moreover, the meat may not come from an animal that has some kind of physical condition that will cause its death. If it is diseased, has a birth defect, is mortally wounded, has a defective organ or limb which will lead to its demise, or is otherwise close to death, either due to frailty, old age or sickness; that animal is called a treifah (טריפה) and is forbidden to eat.
In his magnum opus, Mishneh Torah, Maimonides gives a complete list of seventy defects that render an animal treifah. Only the symptoms mentioned there render it so and no others. If medical science would determine that an animal will imminently die from different causes, this would have no bearing on the kosher status of an animal. In the same vein, if science would determine that a defect which is included in the list is not so serious and does not indicate imminent death, the animal would still be considered to be a treifah and would be forbidden.