Optimizing Ruminal Fermentation with Organic Acids

Much interest has been generated over the past few years aimed at evaluating alternative means to manipulate the gastrointestinal microflora in production livestock. Motivation for examining these alternatives comes from increasing public scrutiny about the use of antibiotics in the animal feed industry. However, compared to the amount of information available detailing the effects of antimicrobial compounds on ruminal fermentation, little research has been conducted to evaluate alternatives to antimicrobial compounds. In the past 10 yr, interest has increased in direct-fed microbial (DFM) products and research has been conducted to examine the effects of DFM on ruminant performance. While some of these products have shown promise in favorably altering the ruminal fermentation and improving animal performance, the effects are variable and inconsistent (Martin and Nisbet, 1992). Recent research has shown that organic acids stimulate growth of the prominent ruminal bacterium Selenomonas ruminantium, favorably alter the mixed ruminal microorganism fermentation, and improve the performance of feedlot steers (Nisbet and Martin, 1990, 1991, 1993, 1994; Callaway and Martin, 1996; Martin et al., 1999). Therefore, the objective of this paper is to provide an overview of this research with organic acids and discuss the potential applications in beef and dairy cattle.