Fibre digestion is fundamental to the productivity of intensively reared beef cattle. It underpins energy availability, weight gain, and overall health. However, when cattle are transitioned onto high-concentrate, starch-rich rations – particularly during the finishing phase – the rumen environment can be compromised. This often leads to acute or subacute rumen acidosis (SARA), a condition that disrupts microbial balance, impairs digestion, and ultimately reduces animal performance.
SARA is one of the most significant nutritional disorders in global beef production, with both economic and animal welfare implications. It arises primarily due to the overconsumption of rapidly fermentable carbohydrates and an abrupt dietary shift from forage to cereals. As a result, excessive volatile fatty acids and lactic acid accumulate in the rumen, lowering pH and overwhelming the rumen’s natural buffering systems. In these acidic conditions, beneficial rumen microbes struggle to function effectively, leading to inefficient fermentation and poor nutrient absorption.
While acute acidosis is associated with visible symptoms such as bloating, diarrhoea, and lethargy, SARA is more insidious. Cattle may show few overt signs in the short term beyond a subtle drop in feed intake. Over time, however, this seemingly mild disruption can lead to more serious health problems, including liver abscesses, laminitis, gastrointestinal inflammation, and even behavioural changes such as increased aggression or mounting.
Given the challenge that SARA presents, a common question among beef producers is how best to support rumen health and maximise fibre digestion – especially during dietary transitions. One effective strategy involves the use of rumen buffers.
Comparing Rumen Buffers: Sodium Bicarbonate vs. Acid Buf
Sodium bicarbonate is widely used in beef diets to neutralise excess acid and support rumen function. However, recent research has shown that the marine-derived buffer, Acid Buf, may offer superior, longer-lasting pH control.
A study conducted by Rossi and colleagues at a northern Italian finishing unit investigated the performance impact of these two buffering strategies. Over a 130-day period, 180 Charolaise bulls were split into two groups. One group received the standard 80 grams of sodium bicarbonate per head per day, while the other was given 40 grams of Acid Buf. Both buffers were included in the mineral premix and fed as part of a consistent, ad libitum ration. The sodium content in the diet was balanced across treatments by adjusting salt inclusion.
Rumen pH was monitored using boluses that recorded readings every 10 minutes throughout the day. The results were striking. Cattle fed Acid Buf maintained a significantly higher average rumen pH compared to those receiving sodium bicarbonate. More importantly, during the critical adaptation period following the dietary change, the time that rumen pH dropped below the safe threshold of 5.6 was dramatically reduced. While the sodium bicarbonate group spent over four hours per day below this level, cattle on Acid Buf averaged just 12 minutes.
This more stable rumen environment allowed cattle to adapt to their high-starch diets more quickly and effectively. There was also a noticeable reduction in acidosis-related issues. Fewer cases of lameness and bloat were recorded in the Acid Buf group, suggesting improved gut integrity and metabolic stability.
Improved Fibre Digestion and Performance
Beyond rumen pH, the study also evaluated fibre digestion using faecal analysis. Acid Buf improved fermentation efficiency, as evidenced by a greater proportion of fine particles in the manure – an indicator of more complete dry matter digestion. Neutral detergent fibre (NDF) levels in the faeces were lower, while acid detergent fibre (ADF) was higher, reflecting a better breakdown of digestible plant cell wall components.
These physiological improvements translated into real performance gains. Cattle receiving Acid Buf gained an average of 81 grams more per head per day than those on sodium bicarbonate. The largest growth differences emerged during the mid-fattening phase (days 21 to 100), a period when feed conversion efficiency is especially critical. The feed conversion ratio improved by 6%, with Acid Buf-fed cattle requiring just 7.66 kg of dry matter per kilogram of weight gain, compared to 8.18 kg for the sodium bicarbonate group. Notably, these gains were achieved without any increase in feed intake, underlining the enhanced efficiency of nutrient utilisation.
The behavioural data were also noteworthy. Cattle in the Acid Buf group exhibited fewer instances of fighting and mounting, pointing to a calmer, more settled herd dynamic. While seemingly minor, such behavioural shifts can have knock-on benefits for animal welfare and energy expenditure, as well as reduced risk of injury.
Implications for Sustainable Beef Farming
As sustainability becomes a growing priority in livestock production, improving feed efficiency is more important than ever. With input costs rising and pressure mounting to reduce the environmental footprint of meat production, strategies that enhance fibre digestion and reduce the risk of acidosis offer significant value.
This study shows that replacing sodium bicarbonate with a lower inclusion rate of Acid Buf not only supports a healthier rumen environment but also delivers measurable improvements in growth performance and feed conversion. These benefits make Acid Buf a strong contender for inclusion in finishing diets where high-energy rations are used.
By enhancing the rumen’s natural buffering capacity and promoting optimal microbial activity, Acid Buf enables beef producers to make better use of their feed, protect animal health, and move towards more sustainable and profitable production systems.
.
