Subacute ruminal acidosis (SARA): a review

Area of Science:

• Ruminant nutrition and metabolism
• Veterinary internal medicine
• Animal health management

Background:

• Subacute ruminal acidosis (SARA) is a metabolic disorder in ruminants, often triggered by abrupt dietary shifts to high-energy feeds.
• It involves an increase in ruminal short-chained fatty acids (SCFA) and a drop in pH below 5.5.
• SARA poses significant risks during the transition from dry to lactating periods and later in lactation due to dietary imbalances.

Purpose of the Study:

• To elucidate the causes and consequences of Subacute Ruminal Acidosis (SARA) in cattle.
• To highlight SARA as a herd management issue requiring a comprehensive diagnostic and preventive approach.
• To emphasize proactive feeding strategies over therapeutic interventions for SARA control.

Main Methods:

• Review of existing literature on SARA etiology, pathogenesis, and clinical manifestations.
• Discussion of diagnostic approaches, including herd screening via rumenocentesis on a sample group.
• Analysis of preventive strategies focusing on ruminant feeding principles.

Main Results:

• SARA is linked to rapid diet changes, inadequate fiber, and incorrect roughage/concentrate ratios, especially in early lactation.
• Consequences include laminitis, parakeratosis, pathogen translocation, inflammation, abscesses, and milk-fat depression (MFD).
• Herd screening using rumenocentesis can identify SARA, particularly in at-risk groups.

Conclusions:

• Effective SARA prevention relies on meticulous transition management from dry to lactating diets and stringent control over diet fiber content and ration quality.
• Proactive dietary management is more effective than using buffers or antibiotics.
• Understanding SARA as a herd management challenge is crucial for diagnosis and control.