all depends on what type of land and what type of grass you have. in my river and creek bottoms i can run 2 pair to the acre from april 1 until jan 1, on my worst hill ground it is 1 pair to 5 acres, in a normal rain year. probably everyone on the board has a little different ratio being from different areas and different soil and weather conditions. it will probably be best visit with local cattlemen in your area to get a better idea, there are some on this board from va, i am sure they can help.