Aspects of Acidosis in Ruminants with a Focus on Nutrition: A Review

An increased risk of acidosis in animals is associated with a high dry matter intake (DMI), which in turn results in the consumption of more fermentable organic matter (OM) in the rumen leading to a high production of volatile fatty acids (VFA). This is observed in lactating dairy cows and animals in a feedlot. Acute acidosis occurs when there is a severe drop in the pH of the rumen. A prolonged period when pH of in rumen remains low, it leads to sub-acute ruminal acidosis (SARA), which is a temporary imbalance between acid production and absorption. An associated change of an acute increase in the ruminal osmolarity and the accumulation of glucose and lactate in its stereoisomeric forms (D-lactate and L-lactate), is observed in the rumen fluid. However, in the sub-acute form, the accumulation of lactic acid occurs in the rumen. To a great extent, these changes in the rumen are due to high concentrations of VFA. The best way to avoid problems with ruminal acidosis is an adequate supply of neutral detergent fiber (NDF) in the diet, preferentially with large particle size and length to stimulate rumination and consequently greater buffering efficiency, thus maintaining the balance between pH and microorganisms in the rumen.