Axle boots are exposed to some of the most rigorous conditions like
road debris, oil, exposure to the elements, and
so on.
Nails that are too long, or torn; the skeleton being off kilter,
so the paws are taking more pressure than they should have to;
debris such as pine needles, sticky weeds, tiny bits of gravel between the toes, ticks buried between the toes, salt from winter
roads, hot pavement, lawn chemicals that cause a burning feeling; growths / tumors, and even cancerous lesions.