Ruminal Acidosis – Much More Than pH

Studies show that acidosis is a very significant disorder of cattle. Studies in Wisconsin found that 20.1 and 23% of cows had subacute acidosis as defined by rumen pH < 5.5 (Oetzel et al., 1999, Oetzel, 2004) and others in Ireland had 11% (O'Grady et al., 2008). A large Australian study found that 10% of dairy cows less than 100 days in milk had acidosis, as defined by assessment of ruminal VFA, ammonia, lactic acid, and pH (Bramley et al., 2008). Therefore, it is likely that many cows will experience some level of acidosis during lactation and, indeed, some may be affected many times. It can be estimated that if the prevalence of subacute acidosis is 10% (Bramley et al., 2008) and the duration of a case is 2 days based on data by Golder et al. (2014b), then there would be an incidence of approximately 1500 cases over a 300 d lactation per 100 cows. Understanding and controlling acidosis is therefore critical to ensuring animal well-being and production.