Technical Abstract: Grazing behavior and diet selection of grazing ruminants can be influenced by a lot of factors. Firstly, they learn from their dams. Secondly, they learn from peers. Thirdly, they learn by trial and error. Work at our USDA-ARS lab showed that ‘ruminal fill’, or how ‘hungry’ the cow is, can affect grazing behavior. The cows that had less ruminal fill took a bigger bite that was shallow and wide, compared to a ‘full’ cow that took a deeper, narrower bite from the pasture sward. This was a result of the ‘hungrier’ cow attempting to harvest the greatest nutrient density with each bite. In addition to learned behavior, farm managers can influence grazing behavior of cows based on management decisions, including what and when to supplement cows in the barn, and when to turn them out on pasture. Farm goals must be combined with what is known about grazing behavior to decide when and how to feed cows. Pasturing cows directly after milking may impact grazing behavior differently than if they’re fed their conserved feeds prior to being turned out on pasture. Pasturing cows only at night may impact their grazing behavior due to preference changes throughout the day. If pasture utilization is to be maximized, or if we’re dealing with a certain pasture quality, we may need to be flexible in what and when we supplement our cows to optimize their utilization of our pastures.