How a rumen buffer drives dairy performance

High dairy performance is related to very fermentable dairy cow diets to meet their nutrient demands. Such fermentable diets lead to increased concentrations of volatile fatty acids (VFAs) in the rumen, which can accumulate leading to periods of reduced rumen pH (Whelan, et al., 2013). Hence, cattle have challenges with rumen acidosis and dairy performance is under pressure.

Formulating diets to provide adequate energy levels while also supplementing sufficient physically effective fibre to prevent rumen acidosis is extremely difficult and, in many cases, unsuccessful. Dietary mineral supplements such as rumen buffers can be very effective tools at regulating rumen pH and preventing some of the negative health and productive consequences associated with low rumen pH.

The definition of sub-acute ruminal acidosis (SARA) is a decline in rumen pH below 5.6 for more than 3 hours per head per day (Gozho et al., 2005). On farm diagnosis of SARA is difficult. The most common method of diagnosis is through rumenocentesis carried out 2 to 4 hours after feeding and SARA is defined as > 3 cows out of 12 measuring a rumen pH of less than 5.5.

The prevalence of SARA is significant with up to 20% of dairy cows, in herds throughout the world, suffering from SARA (Kleen et al., 2013). According to O’Grady and co-workers (2008), cows consuming predominantly pasture diets can also suffer from SARA.

The following periods and feeding strategies increase the risk of SARA:

  • transition period
  • peak milk production
  • peak dry matter intake
  • feeding cattle diets high in starch & sugar
  • cattle diets lacking in physically effective fibre

Prolonged periods of low rumen pH or SARA can have many negative health and productive consequences, such as:

  • reduced abundance of beneficial rumen microbial populations
  • reduced milk composition, especially milk butterfat production
  • reduced fibre digestion
  • inflammation
  • diarrhoea
  • liver abscesses

A novel rumen buffer

Acid Buf has been used in ruminant diets as a novel rumen buffer for many years now. Acid Buf is derived from marine algae, and a 100% natural animal feed ingredient. Its unique marine mineral matrix consumes excess acid in the rumen and regulates long term optimum pH in the rumen. Simultaneously, Acid Buf provides 74 rumen soluble minerals, such as calcium and magnesium. More details regarding rumen bioavailable minerals are described in the article “How to reduce the risk for grass staggers?”.

Previous research, from three different institutes, have reported increased dairy performance:

  • Acid Buf increased feed efficiency (Bernard et al., 2014)
  • Acid Buf increased rumen pH and fermentation (Cruywagen et al., 2015)
  • Acid Buf improved dry matter intake (DMI) and milk protein production in early lactation (Wu et al., 2015)

The most recent work on Acid Buf was carried out at the University College Dublin (UCD) by Neville and co-workers, and published in the Journal of Dairy Science in 2019. As part of this work, two experiments were carried out;

  • Experiment 1 (Rumen pH) utilised three rumen cannulated cows in a Latin square experiment design
  • Experiment 2 (Milk production) consisted of 42 intact dairy cows in a randomised complete block design with a starting days in milk (DIM) of 62 days

The objective of the experiments were to examine the effects of Acid Buf, in comparison to sodium bicarbonate and a control diet on rumen pH, milk production and feed efficiency parameters in mid-lactation dairy cows. The dairy cows were fed a TMR based on a combination of ryegrass silage, corn silage and ingredients typical of a European feeding system.

Acid Buf improves rumen pH

The work of Neville et al. (2019) clearly demonstrates that:

  • Acid Buf increased mean rumen pH compared to control at 2-4 hour, 6-8 hour, 8-10 hour and 10-12 hour after feeding
  • Acid Buf maintained a higher daily (24 hour) mean pH and reduced the time spent below pH 5.5 compared to the control group
  • Acid Buf also increased mean rumen pH compared to sodium bicarbonate at 4-6 hour and 8-10 hour after feeding
  • The sodium bicarbonate group spent more time below pH 5.5 compared to Acid Buf
Experiment 1: results rumen pH relative to feeding time (Neville et al. 2019)

Acid Buf increases rumen pH

x,y Means within a row with different superscripts differ (P< 0.10)
a,b Means within a row with different superscripts differ (P< 0.05)

The peer reviewed publication of Neville et al. (2019) confirms that Acid Buf is also beneficial in a rumen friendly cattle diet and reduces the risk for rumen acidosis. When comparing rumen pH across the treatments, control diet showed a rumen pH remaining below 5.5 for 6 hours in the day. Sodium bicarbonate reduced this to 3 hours and less than 1 hour for the Acid Buf.

Video: results rumen pH and acidosis (Neville et al. 2019)

Acid Buf drives dairy performance

Optimising rumen pH and rumen fermentation results in a clear response to increased production performance. The results of Experiment 2 show that:

  • Sodium bicarbonate increased dry matter intake (DMI) compared to the control, and was similar compared to Acid Buf
  • Acid Buf increased the production of milk butterfat compared to all other treatments
  • Acid Buf resulted in greater milk protein composition than sodium bicarbonate
  • Feed efficiency measured as energy-corrected milk efficiency (kg ECM/ kg DMI) was best for the Acid Buf treatment compared to sodium bicarbonate
  • Acid Buf yielded 120 ml more milk per kg dry matter intake
Experiment 2: results feed intake, milk production & feed efficiency (Neville et al. 2019)

Acid Buf increased the production of milk butterfat

x,y Means within a row with different superscripts differ (P< 0.10)
a,b,c Means within a row with different superscripts differ (P< 0.05)


The addition of Acid Buf to “rumen friendly” dairy cow diets based on a combination of ryegrass and corn silage can effectively maintain rumen pH throughout the day. These effects on rumen pH explains subsequent increases in milk butterfat and protein production observed during Experiment 2.

The use of Acid Buf in this study demonstrates significant increases in total milk solids production which will have economic benefits for dairy producers. This paper will also help dairy producers and nutritionists when comparing different types of rumen buffers.

Acid Buf showed feed efficiency benefits, which may become far reaching in the future. Sustainable farming and environmental constraints force dairy producers to optimise milk production per kilo of feed consumed by the dairy cow.

The work of Neville et al. (2019) confirms the results and conclusions of Cruywagen et al. (2015). Both papers show that Acid Buf works in rumen friendly and rumen challenging diets. Further details on the work of Cruywagen and co-workers is presented in the article “How to increase milk butterfat?”.

The paper of Neville and co-workers is published in the Journal of Dairy Science. Download the full article here and get powered by our science.

Acid Buf offers nutritional solutions for:

  • increasing milk yield and milk butterfat
  • long term pH optimisation in the rumen
  • healthy rumen functioning, reducing subclinical rumen acidosis (SARA)
  • increasing productivity per kg dry matter intake
  • global agriculture sustainability goals

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