Goats undergo experiments for bone implants, respiratory physiology, and TMJ syndrome. Sheep are widely used for both invasive and noninvasive research, and are commonly used as fetal research models. They're used primarily in cardiovascular, dermatology, infectious disease research, and organ transplant. Because their nearly hairless bodies are much more like humans, burn study research on pigs continues. In bullet wound research, the animals are immobilized and shot at close range.
Students then perform surgeries in the hope they'll learn something about battle medicine.
In the early 1950s, some pigs were immobilized in pits and pens, and others were left to wander the Nevada desert, during experiments on atomic weaponry testing. Immobilized in metal stalls, tethered to designated areas, and left wandering on the open decks, pigs, goats and sheep were the unwitting recipients of a full-on blast of an atomic bomb. There were no survivors. A few years later, in 1951, donkeys were subjected to lethal radiation doses. Again, no survivors.