Provided are various embodiments relating to feline erythropoietin (EPO) polypeptide analogs with one or more additional glycosylation sites and methods of producing and using the same to treat anemia in companion animals. Also provided are various embodiments relating to EPO polypeptides having a mutation in the second binding site, polypeptides comprising an extracellular domain of EPO receptor, and methods of using the same for treating polycythemia in mammals.