In conclusion, 12-h ACTH infusion in ovariectomized cows stimulated cortisol secretion and elevated the plasma cortisol concentration for 18 h. Cows infused with ACTH solution exhibited hypophosphatemia, indicating disturbance of Pi homeostasis by cortisol. Additionally, increased cortisol secretion following ACTH infusion decreased levels of bone resorption and formation markers, indicating its suppressive effect on bone metabolism in ovariectomized cows without the involvement of gonadal steroid hormones