Speed, Duration of Impact, and More Helps TIMAB Magnesium’s pHix-Up Stand Out Among Rumen Buffer Products – INDUSTRY PERSPECTIVES

Although its prevalence can vary significantly by region and production system, the problem of subacute ruminal acidosis (SARA) is understood to be extensive, affecting an estimated 20-25% of dairy cows, mainly in early to mid-lactation, and up to 40% of beef cattle, especially during the finishing phase in feedlots. It is caused by Non-Fiber Carbohydrates, which correspond to starch and sugar content. After being ingested, a high energy ration will result in a fast accumulation of Volatile Fatty Acids above the natural buffering capacity, leading to a decrease in the rumen pH.

It is generally considered that cows experience SARA when rumen pH drops below 5.8 for more than 3 hours per day. Low pH can increase the permeability of the rumen wall by damaging it, which provokes an increased risk of having toxins going from the rumen to the blood and to the different organs. This opens the door to other pathologies like lameness or liver abscesses. Moreover, the decreased feed intake linked to acidosis can also cause a decrease of the milk yield and milk fat. Because of all these elements, SARA has a strong economic impact for the farmer, including direct and indirect costs.

With its pHix-up product, minerals company TIMAB Magnesium believes it has found a new innovative way to balance the rumen pH, one that strikes an optimal balance between quick action, long-lasting impacts, and cost-effectiveness. Today, Mélody Baudon and Ashley Driemel, ruminants product managers at the company, take us through the product’s modes of action and discuss how it can aid farmers navigating particularly challenging periods from heat stress to pre-partum to spring grazing.

Chemically speaking, magnesium oxides are alkalizers with a strong theoretical potential to increase pH. This effect depends on the specific surface area, which is the ratio between the real surface of a product according to its quantity. The surface area will directly affect solubility and reactivity.

In practice, the surface area varies a lot between MgO sources, which means that you cannot predict what will be the effect on rumen pH with one single source of MgO. This variability is mainly due to:

• The granulometry: a fine source is more likely reactive and soluble
• The calcination process: MgO comes generally from heated magnesium carbonate (MgCO₃). The temperature of calcination is a very important factor to take into account to express the best characteristics of a MgO source. If MgCO₃ is heated too high or too low, the solubility and reactivity of the source will be impacted
• The origin: surface area will also be dependent on the impurities present in the original rock, something which differs according to the area considered

With pHix-up, the pH is maintained throughout the day and between two meals: the drop of pH after intake is avoided and the pH is stabilised, providing a continuous effect up to the next ration distribution.

It’s important to mention that pHix-up can be used either in total mixed ration directly at the farm or included inside a mineral or a complete feed. We recommend a dosage between 0.2 and 0.5% of the dry matter intake for all ruminant species.

[Feedinfo] How does pHix-up compare to other rumen buffer products? Why are the solubility, the speed of action, and the length of action of different buffering solutions important?

[Mélody Baudon] Several products on the market today can be used to neutralise the acids in the rumen. The efficiency of a product to act on pH can be determined by its neutralising capacity and its solubility, which give an idea of the kinetic of action. To maintain a steady pH throughout the day, it is necessary to have a product that will act quickly after the feeding, but which will also have a long-lasting effect.

Sodium bicarbonate is the most well-known product and the most widely used across the world. It has a low neutralising capacity of 12mEq/g, with a very high solubility. For that reason, the minimum recommended dosage of sodium bicarbonate to have a real impact is 1% of dry matter intake (DMI), which is quite expensive per cow per day.

Another solution that is commonly used is lithothamnium, which is calcium carbonate from marine algae. Lithothamnium has a higher neutralising capacity of 20mEq/g but a very low solubility at the rumen pH. Once in the abomasum, at pH 2.5, this solution will solubilise, and from that point serves as a good source of calcium, as this later is mainly absorbed in the intestine. However, without being solubilised in the rumen, lithothamnium cannot have a fast action on the pH to avoid its decrease after feeding.

Comparatively, pHix-up’s neutralising capacity is 39mEq/g, more than 3 times higher than the neutralising capacity of sodium bicarbonate. Thanks to the blend mentioned previously, pHix-up also has the capacity to solubilise very quickly after the feeding, in addition to its action on rumen pH over time.

Consequently, pHix-up dosage can be 3 times lower than sodium bicarbonate dosage. For example, if a buffer mix contains 200g of sodium bicarbonate and 50g of MgO, both products can be removed and replaced with a mere 80g of pHix-up for the same performance. This brings an economical gain and a space gain in the minerals portion of the diet. It’s also possible to have a blend of 65g of sodium bicarbonate and 65g of pHix-up to maintain the dietary sodium level while expecting the same performance with an economical gain.

This was proven several times at the Roullier Innovation Center in artificial rumen juice and in on-farm trials in different countries across the world.

[Feedinfo] A change in the rumen environment will also have an influence on the microbiome. What have you seen on this front when deploying pHix-up, and what are the implications for fiber degradation (and ultimately for the ration as a whole)?

[Ashley Driemel] Indeed, it is widely acknowledged that the rumen microbiome is strongly influenced by rumen environment conditions, especially by pH. A stable rumen pH within the optimal pH range will favour the balance of cellulolytic and amylolytic bacteria in the rumen.

In our last experimental study with Professor Alex Bach at Blanca Experimental Station in Spain in 2021, one of our first objectives was to study the effect of the use of pHix-up on the microbiome and specifically, the Fibrobacter population abundance.

The design was composed of 3 groups: control, sodium bicarbonate at 200g per cow per day and pHix-up at 62g (1/3 the sodium bicarbonate dosage). During a grain challenge period, SARA was induced by replacing 1kg of forage with 1kg of barley 4 times, at intervals of two weeks. The trial started with 52% of dietary concentrates in the first period and ended with 64% in the last period.

Regarding pH, time spent below a rumen pH of 5.8 was lower in pHix-up cows, and pH was stabilised: maximum pH was reduced and minimum pH was increased compared to control and sodium bicarbonate groups.

With the SARA induced challenge, Fibrobacter population abundance was clearly impacted with a significant reduction as dietary concentrate level was increased. On the contrary, when looking at the groups, abundance of Fibrobacter significantly increased with the use of pHix-up compared to the 2 other treatments.

Thanks to pHix-up’s ability to stabilise the rumen pH, the Fibrobacter population proliferated in this study. This in turn led to a significant improvement in NDF (Neutral Detergent Fiber) digestibility compared to the other treatments, especially at the highest dietary concentrate level.

[Feedinfo] Beyond its use in regulating the pH of the rumen, pHix-up is also a highly soluble magnesium source. Why is that beneficial for the animal? And do feed formulators need to include more in the diet if they want to take full advantage of this aspect of the product?

[Mélody Baudon] Magnesium participates in more than 300 enzymatic reactions in the organism: bone structure, stress reduction, milk fat synthesis in the mammary tissue, calcium regulation, muscle contraction, etc. Therefore, it is essential to the health of the animal that a soluble, bioavailable source of magnesium is fed.

As mentioned previously, there is a large variability between MgO sources. Classic magnesium oxides usually release around 30% of their Mg content after 6h of fermentation in in vitro systems, compared to 70% with pHix-up. This is due to the different MgO sources within pHix-up that have both quick and slow solubilities, allowing for a continuous regulation of rumen pH.

Unlike the majority of minerals, magnesium is mainly absorbed in the rumen. It is thus very important to have a product that will solubilise in that part of the digestive tract, also taking into account the negative interaction that exists with potassium: the more potassium you have in the ration, the lower the absorption of magnesium will be.

[Ashley Driemel] There are three periods where pHix-up is particularly interesting thanks to this combination of effects on pH and its highly soluble magnesium content.

• Heat stress: During these periods, animals are more sensitive and dedicate a large portion of their energy towards regulating their body temperature, which often negatively impacts performance. As potassium will be excreted in sweat, it is strongly advised to increase its supply in the ration during times of heat stress. But, because of the negative interaction between Mg and K, it is also important to consider increasing the dietary Mg level to account for mineral imbalances.
• Prepartum: A common practice is for producers to adapt their cows to mobilizing calcium from the ration and from their bones before calving. As magnesium is an essential player in calcium regulation, it is important to adapt its supply in the ration as well. Maintaining optimal rumen pH is also a challenge, especially during the close-up period. During this time 3 weeks before calving, concentrates are progressively reintroduced into the ration so the cow can adequately meet energetic requirements associated with calving such as milk production.
• Spring grazing: Young forages are richer in potassium and carbohydrates. For that reason, it is important to adapt dietary magnesium to properly neutralise excess acid produced in the rumen.

[Feedinfo] TIMAB Magnesium began development on pHix-up in 2015, I believe. Can you tell me about that journey? How have you continued refining the product, or advancing your understanding of it, in recent years? 

[Mélody Baudon] TIMAB Magnesium has a true expertise in magnesium, having been an actor in this sector for more than 40 years in different applications: refractory, industrial and agricultural.

In 2015, the company decided to invest in R&D to start the development of specialty products, looking for magnesium-based solutions to address livestock farming’s issues. That’s the beginning of pHix-up’s journey! After 3 years of research to select the right Mg sources with the right origins and manufacturing process, pHix-up was commercialized.

Since then, we developed a particularly strong foothold in Europe and Latin America. The journey isn’t finished yet, as we are now starting discussions in new markets in the Middle East and Asia, where pHix-up could be a very interesting opportunity in highly intensive systems with heat stress.

We are also thinking about how to improve in order to be as close as possible to our clients’ needs, which is only possible thanks to the good relationships we are able to create between our clients, sales team and technical team.

Published in association with TIMAB Magnesium