Ruminal Acidosis: A Systematic Review

Ruminal acidosis is a metabolic disorder that affects ruminants, including cattle, sheep, and goats, due to a pH imbalance in the rumen. The rumen has a diverse population of microorganisms involved in carbohydrate metabolism, with anaerobic microorganisms in the rumen and cecum playing a crucial role. During healthy rumen metabolism, microbial fermentation produces volatile fatty acids, including acetic acid, propionic acid, and butyric acid. Excessive intake of feeds with high soluble carbohydrate content can cause ruminal acidosis by altering the ratio of volatile fatty acids produced through microbial fermentation, which in turn changes the rumen pH. Acidosis is defined as a decrease in the alkalinity of body fluids relative to their acid content. The pH of body fluids may or may not decrease during acidosis, depending on the degree of bicarbonate compensation. Impaired central nervous system function can occur even if blood pH remains stable due to low bicarbonate concentrations, which are buffered by bicarbonate. While a blood pH below 7.35 is required for a clinical diagnosis of acidosis, other clinical signs such as ruminal pH, anorexia, variable feed intake, diarrhea, and lethargy are commonly used to diagnose acidosis in beef cattle.