• Acid Buf improves feed efficiency and dairy sustainability

Improving feed efficiency in dairy cows

Feed efficiency in dairy cows can be defined as the fraction of feed energy captured in saleable products (VandeHaar et al., 2016). It allows dairy producers to utilise their resources more effectively. This subsequently improves the profitability, sustainability, and environmental impact of their dairy business.

For many years, the Feed Conversion Ratio (FCR) has been used in the pig, poultry, and beef industries as a measure of efficiency. Within these sectors, the FCR of an animal was used as a key performance indicator (KPI) for their business and was closely associated with the profitability of that production system. However, the dairy industry has been much slower to incorporate feed efficiency measurements when analysing the success of their production systems.

Therefore, understanding the different measurements of efficiency and understanding how to improve such efficiency measurements will be of increased importance. Milk production efficiency or dairy efficiency is defined as kg’s of energy or milk butterfat corrected milk produced per kg of dry matter intake (DMI) consumed by dairy cows.

Some of the main factors that influence feed efficiency in dairy cows are:

  • genetics
  • stage of lactation
  • health status
  • nutrition

Feed efficiency boosts dairy sustainability

Despite the lack of uptake in feed efficiency measurements at farm level, feed efficiency in dairy cattle is important. Increased feed efficiency results in reduced greenhouse gas emissions (Knapp et al., 2014). A study by Capper et al. (2009) reported a 60% reduction in greenhouse gas emissions per unit of milk produced on US dairy farms over the past 60 years. Most of this reduction is coming from increased feed efficiency.

Improvements in feed efficiency will lead to less land and resources required for feed production (von Keyserlingk et al., 2013). This is important in the context of a growing human population as less land will be available for growing feed for dairy cows. Increasing output of usable products from each unit of feed input will result in less nutrients being wasted or excreted out of the dairy cow. This will have benefits in a dairy industry that may face tougher environmental constraints around manure storage and spreading on land. Finally, with feed costs cited as one of the most significant costs in dairy production, improvements in feed efficiency will have direct effects on farm profitability through a reduction in feed required per unit of output.

Dry Matter Intake vs. Feed Efficiency

More specifically to diet, the digestion system of a dairy cow plays a huge role in determining the level of feed efficiency achieved. The rumen is central to this digestion process. The ruminal inhabitants (microbial population) have a large influence on how nutrients are extracted from a particular feedstuff and converted into metabolic fuels for the dairy cow.

Traditionally, dairy nutritionists have emphasised on maximising dry matter intake (DMI) in dairy cows as a way of increasing milk production. However, increasing DMI may not always result in favourable productive outcomes. The “law of diminishing returns” may kick in and subsequently, nutrient digestibility decreases with increasing DMI.

As DMI increases, the feedstuffs spend less time in the rumen being digested by the rumen microbial population. Hence, less nutrients are utilised from the feed so more nutrients pass through to the lower digestive tract and are excreted out of the dairy cow. Changes in the rumen microbial population also have a big impact on the efficiency of rumen digestion.

Maintaining a stable environment for the rumen microbial populations by minimising changes in rumen pH allows starch, sugar, and fibre digesting bacteria to live in harmony digesting the range of carbohydrates consumed by the dairy cow.

Most rumen microbes are pH dependant so a daily fluctuating rumen pH will lead to the deterioration of certain bacteria and the rumen will be unable to cater for the range of carbohydrates ingested by the cow. To combat these changes in rumen pH and fluctuating rumen microbial profile, dairy cow nutritionists should ensure diets contain sufficient effective fibre and limit the amount of starch and sugars that are included in the dairy cow’s diet.

Feed additives can also be used as effective tools in maintaining a stable rumen pH. One of the feed additives getting more attraction in recent years to enhance feed effiency and reduce the risk for rumen acidosis is Acid Buf, produced by Celtic Sea Minerals. Acid Buf is a 100% natural animal feed ingredient. It meets the nutrient requirements for dairy nutrition. The basis is a marine mineral complex with 74 bioavailable minerals. The product has proven to affect rumen pH regulation and feed efficiency.

Video: Rumen pH and VFA production (Van Soest 1994)

Acid Buf improves feed efficiency

Research done at Georgia University in the USA in early lactation Holstein dairy cows compared 90 g/head/day Acid Buf to a control and a sodium bicarbonate treatment at 180 g/head/day. Dairy cows were fed a high NDF diet based on maize silage and ingredients typical of a US dairy feeding system. Researchers from this study reported an increase in feed efficiency with Acid Buf inclusion. Compared to the control and the sodium bicarbonate treatment, Acid Buf increased energy-corrected milk yield (ECM) by 0.2 kg per kg dry matter intake (Bernard et al., 2014).

Following from the work in Georgia, researchers at Stellenbosch University in South Africa conducted an experiment comparing 90 g/head/day Acid Buf to a control diet and a 180 g/head/day sodium bicarbonate diet to cannulated dairy cows. Cattle were fed a high starch, low NDF total mixed ration based on maize grain and hay. Results of this study confirm the trends seen in Georgia. The Acid Buf treatment yielded an increase of 0.24 kg of fat-corrected milk (FCM) per kg dry matter intake compared to control. Compared to sodium bicarbonate, Acid Buf increased milk yield by 0.17 kg FCM per kg of DMI (Cruywagen et al., 2015).

The most recent work was carried out at University College Dublin in Ireland. Researchers compared 80 g/head/day Acid Buf to a control and a 160 g/head/day sodium bicarbonate diet in mid-lactation dairy cows. Cattle were fed a TMR based on ryegrass silage, maize silage and other ingredients typical of a Northern European feeding system. The outputs of this experiment further cemented the beneficial effects of Acid Buf that were previously reported in Georgia and Stellenbosch. Acid Buf increased the ECM by 0.13 kg per kg DMI compared to the sodium bicarbonate treatment (Neville et al., 2019).

The consistent improvements in feed efficiency due to Acid Buf has been proven in 3 very different feeding systems on 3 different continents. Hence, science confirms that the average efficiency improvement with Acid Buf is in the range of 3 to 4 kg extra milk based on 22 to 23 kg daily DMI.

Acid Buf provides dairy producers and nutritionists with an effective tool for increasing feed efficiency. And not only that. Acid Buf helps the animal feed and dairy businesses towards sustainable farming and an environmentally friendly future.

Increasing milk production efficiency will also lead to increased margin over feed costs and subsequent improvements in farm profitability. For example, a difference of 0.1 kg’s ECM per kg DMI per day in a dairy cow yielding 35 kg of milk per day can lead to an increased margin of $0.50 per cow per day over feed costs.

Summary of Feed Efficiency outcomes in experiments using Acid Buf in dairy cow diets

The consistent improvements in feed efficiency due to Acid Buf has been proven in 3 very different feeding systems on 3 different continents.


To conclude, feed efficiency measurements will need to be embraced by dairy producers. Success can be achieved with the right approach. When balancing diets for dairy cows, it will be important to understand the conflicting nature of DMI and rumen digestion so we can promote optimum DMI as opposed to maximum DMI for high producing dairy cows. The focus on the rumen microbiome will need to be centred on creating an optimum environment for different species of microbes to leave the rumen in a position to extract nutrients from all types of carbohydrates.

Maintaining an optimum environment for these microbes can start with reducing rumen pH changes. More information about the effects of Acid Buf on rumen pH can be found in the article “How a rumen buffer drives dairy performance”. Acid Buf is a nutritional solution that can be used to increase feed efficiency on dairy farms through promoting an optimum rumen environment for the digestion of feedstuffs.

The optimum environment for rumen microbes due to Acid Buf will help animal feed producers and dairy businesses to meet the global agricultural sustainability goals!

Acid Buf offers nutritional solutions for:

  • increased productivity per kg dry matter intake
  • increased milk yield and milk solids
  • healthy rumen functioning
  • global agriculture sustainability goals

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