05.13.601 is a part of the 4th edition of the Ettinger Textbook of Veterinary Internal Medicine, which is a comprehensive textbook of veterinary medicine covering all the major body systems. This particular part of the book covers endocrine system diseases, including thyroid, parathyroid, adrenal, and pituitary diseases, as well as diabetes mellitus, acromegaly, and Addison’s disease. It discusses diagnosis and management of endocrine system disorders, including treatments, prognosis, and complications, and reviews common laboratory tests used to diagnose and monitor endocrine disorders.