Improve rumen health, enhance farming profitability
Subacute Ruminal Acidosis (SARA) is a silent disruptor in dairy farming and can reduce feed intake, lower milk fat, and slow daily weight gain. Including yeast cultures is a highly effective strategy to promote rumen health and mitigate the effects of SARA.
In recent years, intensive feeding practices and high-grain diets for ruminants have become widespread. However, a high proportion of grains leads to rapid carbohydrate fermentation, causing rumen pH to consistently fall below the threshold for SARA. This suppresses the activity of fibrolytic bacteria and triggers lactate accumulation.
In production settings, SARA leads to a decrease in dry matter intake by approximately 15%, a reduction in milk fat percentage in dairy cows by 0.8-1.2 percentage points, and a decrease in daily weight gain in finishing beef cattle by up to 15%-22%. Additionally, damage to the rumen barrier promotes the translocation of endotoxins (LPS), causing systemic inflammation such as rumenitis and laminitis. Statistics show that SARA has caused annual losses of US$5-10 billion in the North American dairy industry, averaging US$1.12 per cow per day.
How we address the microbial dysbiosis caused by SARA
To prevent SARA, besides good feeding management and rational diet formulation, feed additives can be utilised to reduce the risk of SARA occurrence in herds.
Existing control strategies primarily focus on clearing excess acids (especially lactate) and reducing inflammatory factors. Adding live bacteria, such as yeasts, creates an anaerobic environment in the rumen, stimulating the proliferation of Megasphaera elsdenii and increasing lactate utilisation. Adding cell wall components, like β-glucans, promotes the colonization of fibrolytic bacteria (Ruminococcus flavefaciens), improving neutral detergent fibre (NDF) digestibility. Mannan oligosaccharides (MOS) competitively block pathogen adhesion (e.g., E. coli), reducing toxin translocation.
Among these, adding yeast cultures is a highly effective strategy. The live yeast and bioactive cell wall components they contain, along with unique microbial metabolites, improve the rumen microenvironment and enhance the resilience of the rumen microbiota. In a recent study, supplementing high-concentrate fed beef cattle with Angel Yeast rumen-specific regulatory yeast culture (YeaFerm EX125) maintained rumen pH around 6.0~6.5 and increased daily weight gain by 100g per head.
Practical management recommendations
Combine with ventilation/sprinkling measures to avoid rumen oxygen stress caused by heat stress and maintain fibrolytic bacteria activity.Evaluate fermentation efficiency using rumen fluid volatile fatty acid (VFA) profiles, assess concentrate excess through fecal observation, and evaluate acidosis risk by monitoring animal status to enable real-time dynamic adjustments to the feeding programme.Make gradual adjustments to the concentrate-to-forage ratio and minimise the feeding of excessively finely ground straw.
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