Feeding Behavior, Feed Selection and Risk of Digestive Problems in Dairy Cattle

In dairy cattle, the rumen environment is designed to function optimally within a pH range of 6.2 to 7.2. To maintain healthy rumen function, dairy cows require diets that contain adequate amounts of physically effective neutral detergent fiber (peNDF). Ensuring adequate intake of peNDF can, however, be difficult because most commercial dairy rations, designed to maximize milk production, contain high levels of concentrate and high quality forages that are often limiting in peNDF (Beauchemin and Yang, 2005). When ruminants consume excessive amounts of rapidly fermentable (nonfiber) carbohydrates, combined with low intake of peNDF, cows are not able to maximize their rumination time and salivary buffer flow to the rumen, and thus ruminal pH drops below normal physiological levels. Sub-optimal ruminal pH (e.g., pH 5.2 to 5.8) is often referred to as sub-acute ruminal acidosis (SARA) (Owens et al., 1998).