PReVeNtING RUMINAL ACIDosIs IN DAIRY CoWs

Feeding dairy cows for maximum milk production increases the risk of ruminal acidosis. Diets fed to high producing dairy cows in North America are typically highly digestible in the rumen and often lack sufficient physical fiber. Rapid fermentation of carbohydrates causes an accumulation of volatile fatty acids (VFA) in the rumen, leading to a drop in ruminal pH. Lack of sufficient physical fiber in the diet reduces rumination time and the concomitant flow of salivary buffers into the rumen. A high concentration of VFA, combined with a decrease in ruminal buffering, causes prolonged periods of low ruminal pH each day, also referred to as ruminal acidosis. While feeding highly fermentable diets can lead to short-term increases in milk production, the long-term consequences of ruminal acidosis on lameness, susceptibility to metabolic diseases, and cow longevity can be devastating. While it is critical to meet the energy requirements of high producing cows, acidosis must be avoided to ensure high milk production as well as cow health. This paper discusses the factors that predispose dairy cows to acidosis and provides insight into some of the feeding and management opportunities that can be used to help reduce its occurrence.