Prednisone is activated by enzymes in the liver to turn into
prednisolone. They do have similar uses but
prednisolone is more readily absorbed by the body. Prednisolone is usually used when there is liver toxicity or liver failure involved.
There is no great difference between them, other than the above, however ... it is normal practice to begin at a low dosage, rising to a level that's appropriate for the weight of the dog.