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Nutritional management of subacute ruminal acidosis in early lactation.

M. Mosher

Abstract:

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Nutritional management of subacute ruminal acidosis in early lactation.
M. Mosher*, E. Eckelkamp. University of Tennessee Institute of Agriculture Knoxville, TN.

Proper nutrition is key to early lactation management, particularly for subacute ruminal acidosis (SARA). Early lactation is one of the most energy demanding periods of a cow's life. Early lactation marks the end of gestation and parturition and the onset of lactation. Subacute ruminal acidosis is typically defined as the rumen pH dropping below the ideal pH range (6.0 to 6.4) to ≤5.6 for ≥3 h. Low pH can lead to insufficient rumen buffering and decreased production and health issues including: laminitis, gastrointestinal damage, and liver abscesses. Cows with SARA do not exhibit clinical signs leading to missed cases, late diagnosis, or only diagnosing severe cases. Cows with SARA cost the US dairy industry $500 million to $1 billion annually through decreased milk production, decreased milk fat percentage and overall milk quality, and cow mortality. Although treatment is key to all disease management, prevention is key with SARA. Effective SARA prevention relies on proper ration formation. Producers who maintain a forage to grain ratio of 60:40, a high starch percentage, and a low amount of forage neutral detergent fiber can maintain high production with a lower risk of SARA. A grain ratio ≥50% can increase SARA risk and depress milk fat percentage. Too much grain in the diet can lead to excess or abnormal production of volatile fatty acids which can decrease rumen pH. Particle size should also be considered. Particles that are too long (>19 mm) or too short (<4 mm) can lead to an increased risk of SARA. Suggested particle size and distribution were ≤8% of ration ≥19mm, 50% of ration between 7mm to 9mm, 20% of ration between 4mm to 7mm, and 30% of ration ≤4mm. Providing a rumen buffer can also help control SARA, such as sodium sesquicarbonate and sodium bicarbonate. Rumen buffers help stabilize the rumen environment and can be used to bring rumen pH back to ideal levels. Through proper nutrition, control of subacute ruminal acidosis can be increased along with cow health and productivity.

Keywords: early lactation, subacute ruminal acidosis, nutrition.

Biography: I am a Senior in Animal Science at the University of Tennessee. I come from a beef background, and my family still raises Simmental cattle in South Dakota. I have a passion for ruminant nutrition, and will be starting my Masters Degree with Dr. Kendall Swanson at North Dakota State University June 1, 2020.