It all depends on feed resources available, cow weight, stage of gestation, and weather conditions. All these factors impact daily intake of beef cattle. As a general rule, if you have the resources so that the cow can graze and meet her nutrient needs, the lower the feed costs. The most expensive part of the feeding program is when you have to supply harvested feeds to meet the cow's nutrient requirements. In some places in the United States, year-round grazing with very little supplement is possible, in other places it is not. At least in Nebraska, summer rental rates for pasture have tended to have increased over the last 20 years. For a 1200 pound cow, feeds costs annually would be at least between $0.80 and $1.00 per head per day (maybe more) and there are many factors that will impact those numbers.