Frequently Asked Questions

What benefits should I expect to see from feeding Glycal Forte?

Most cows lose body condition after calving. This is a natural response to provide energy for milk production. For a lot of cows the loss of body weight is made worse by reduced dry matter intake, often caused by SARA (sub-acute rumen acidosis). As cows lose weight the breakdown products of fat can cause fatty liver, ketosis, poorer fertility and reduced immune function. Sometimes fat is lost from the digital cushion which can lead to lameness.

If your cows lose too much body condition, show signs of SARA or ketosis, take longer to get back into calf than they should, or a prone to displaced abomasums, metritis or mastitis then you could benefit from feeding Glycal Forte.

In controlled trials and on commercial dairy farms Glycal Forte has been shown to reduce somatic cell counts (an indicator of better immune function), improve fertility efficiency and increase milk yield. The benefits are better health and welfare, and a more profitable dairy herd.

What are the 3 features of Glycal Forte?

Glycal Forte supplies rumen-protected glycerol, highly-available calcium and optimises ruminal pH – all in one product.

How much Glycal Forte should I feed?

250g per cow per day is the recommended feeding rate, but check with your nutritional advisor.

How do I feed Glycal Forte?

When fed in a TMR Glycal Forte is best mixed with a dry feed prior to loading in the feeder wagon. This allows good dispersal throughout the whole of the feed. Adding Glycal Forte to the top of the forages in the feeder wagon may result in uneven intakes of the product.

Can I have Glycal Forte included in a compound feed?

Yes. Tests have shown that Glycal Forte retains its unique features of providing bypass glycerol, highly available calcium and rumen conditioning when incorporated into compound feed.

How long should I feed Glycal Forte for?

You can feed Glycal Forte to your high yielding cows from 21 days pre-calving up to 150 days in milk, or for as long as you feed the high-yielding ration. If you don’t have a high-yield group, but have a “fresh” group then you will still see benefits from feeding 21 days pre-calving to 21 days post calving.

Why is Glycal Forte unique?

Firstly, it is the only rumen-protected glycerol available. Secondly, it adapts its functionality to the needs of each individual cow. Every cow in a herd is different. Even within specific groups such as fresh cows or a high-yielding group each cow is individual and has its own nutrient requirements. The nutritionist formulates a ration for the average cow meaning some will be under-supplied with some nutrients and some will be oversupplied. The under-supplied cows will not be producing at their maximum efficiency; and the over-supplied will be wasting expensive nutrients.

How does Glycal Forte tailor its functionality to each individual cow?

Take ruminal pH as an example. The ideal pH is around 6.0 – 6.4 but we know that up to 40% of cows in any herd (and most cows during the 2 -3 weeks following calving) suffer from sub-acute rumen acidosis (SARA). The trouble is that we don’t know which ones. The way Glycal Forte works is that its dissociation profile varies according to the pH ( this means that in acidic conditions where pH is low Glycal Forte releases more acid-neutralising ions and brings the pH up to the correct level). In those cows with optimal ruminal pH much less dissociation occurs so that more of the Glycal Forte passes through the rumen untouched and therefore more glycerol bypasses the rumen.

Why is tailored-functionality a benefit?

Because the cow benefits whatever its rumen condition. Think about buffers. If you add a buffer to the feed you may be supplying 60% of the cows with something they don’t need and can’t make any use of. In fact, because an alkaline rumen is also bad for the cow; not only are you wasting money but you could be doing harm. With Glycal Forte, if the cows don’t need rumen conditioning more of the glycerol bypasses the rumen and this reduces their risk of getting ketosis.

But, buffers are cheap aren’t they?

They may be cheap to buy, but if they don’t do any good they work out to be expensive to use. Take sodium bicarbonate for example.

It is highly soluble and rapidly eliminated from the rumen. Consequently, it only works for a very limited time and is unable to provide any long-term stabilising effect, unlike Glycal Forte with its slow-release, pH-sensitive, controlled pH regulation mechanism.

Sodium bicarbonate, as with some other rumen buffers can result in very rapid, uncontrolled ruminal pH rises which may adversely affect the rumen environment. Glycal Forte on the other hand, reduces its effect as pH rises and ensures that pH does not go above the optimum.

Sodium bicarbonate loses its buffering ability below optimal ruminal pH levels of above 6. Trials have shown that sodium bicarbonate does not remove lactic acid from the rumen.

To have some effect, sodium bicarbonate requires a relatively high feed rate of up to 200 – 250g, which works out to be expensive for most of the cows and can over-supply sodium.

Sodium bicarbonate can increase rumen outflow rates. This may lead to increased dry matter intakes but reduced rumen fermentation efficiency. The result of this is that the diet is less well digested.

What about limestone? That really is cheap!

No, that really is expensive! Calcium carbonate has little if any buffering action in the rumen. Ground limestone flour has often been recommended as a rumen buffer fed at 100 – 200g per cow on the grounds of price. However, it is in fact largely insoluble above pH 5.5. It is therefore totally unsuitable as a rumen buffer and should not be used as such. Inappropriate use of ground limestone flour can affect other nutrients resulting in trace element deficiency, which can lead to problems with lameness, high somatic cell counts and mastitis.

But, limestone is a good source of calcium, isn’t it?

Not as good as Glycal Forte! When it reaches the abomasum where the optimal pH is below 3, Glycal Forte not only releases its glycerol, but the calcium in the matrix reacts with hydrochloric acid in the abomasum to form water-soluble, bio-available calcium chloride. Fed at 250g per cow per day Glycal Forte provides the cow with around 60g of calcium, an ideal amount especially for a cow in early lactation. The other benefit of Glycal Forte is that it does not cause the pH of the abomasum to rise nearly as much as limestone does. It is important to maintain a low, acidic pH in the abomasum for health and nutritional reasons.

But, what about so-called “natural” limestone-based products? Aren’t they better?

As with many products like this, for those cows that don’t have SARA they provide very little. However, Glycal Forte-fed cows receive 3 benefits; and those that are not suffering from SARA at a given time get extra rumen-protected glycerol and bio-available calcium too. These “natural” products consist mainly of calcium carbonate. It is important to note that calcium carbonate is not water-soluble above pH 5.5 and it therefore does not counter SARA. it cannot be made soluble to function as a buffer by reducing the particle size or by increasing its available surface area.

Why all this fuss about rumen pH anyway? What are the benefits of getting rid of SARA?

Raising the rumen pH saves energy. This is the energy that the rumen microbes would have used in attempting to counter the low ruminal pH. This energy can then be used for milk production. The lower the starting point for pH change, the greater the energy saving. The research into this post-calving pH drop demonstrated that raising pH from 5.5 to 6.0 reduces the energy required for microbial maintenance by over 9MJ per day. This is sufficient energy to fuel the production of nearly 3 litres of milk. In addition, cellulolytic bacteria digest fibres more efficiently at optimal ruminal pH, releasing more energy from the feed.

Finally, an acidic environment can decrease the growth rate of rumen bacteria. As the ruminant is largely dependent on microbes as a protein source, the efficiency of rumen microbial growth is of critical importance to performance. It has been demonstrated that raising pH from 5.5 to 6.0 increases metabolisable protein supply by 6.4% or 168g/day due to faster microbial synthesis. So, the benefits of overcoming SARA are more milk and more profit.

Are there any other benefits from maintaining a healthy ruminal pH?

In addition to benefitting from the extra energy saved by more efficient microbial function (less heat loss and better fibre digestion) raising the ruminal pH promotes dry matter intake. This means there is even more energy available to the cow.

What are the benefits of bypass glycerol?

Glucose is needed for milk production but any that is present in the ration gets fermented in the rumen. Therefore, dairy cows have to synthesise all the glucose that they need. A successful transition period is dependent on increased synthesis of glucose in the liver and the optimal mobilisation of body fat reserves to meet the energetic demands of a rapidly increasing milk flow. However, in high yielding cows this metabolic transition is often impaired, resulting in negative energy balance, ketosis and fatty liver syndrome. Glycerol is a glucose precursor. In other words, it is converted very efficiently in the liver to glucose. But, it needs to be absorbed directly into the blood stream. It therefore needs to bypass the rumen intact without being fermented in the rumen to perform this function.

Why can’t I mix glycerol into the feed?

Glycerol is a viscous liquid, which is difficult to store, handle, transport and mix evenly with feed. In the rumen it ferments quickly generating substantial quantities of carbon dioxide gas and organic acids such as acetic, propionic and butyric acids. These acids reduce fluid pH leading to SARA and ketosis. The fraction converted to butyric acid is metabolized to BHBA by the ruminal epithelium. BHBA is ketogenic rather than glucogenic.  Of these acids, only propionic acid is a precursor to glucose.

Some nutritionists advocate feeding liquid glycerol, either mixed into the TMR or included in compound feed. However, one of the leading experts in the field, A.R. Hippen* states that to be glucogenic, glycerol must either be delivered in water (drenched) or be able to ‘by-pass’ the rumen in some form to be absorbed as glycerol and converted to glucose by the liver.

The glycerol in Glycal Forte does by-pass the rumen, allowing it to be released in the abomasum. It then passes into the small intestine to enter the blood stream via the portal vein and be transported directly to the liver, where it is converted into glucose.

*Hippen, A. R., DeFrain, J. M., and Linke P. L. (2008). Glycerol and other energy sources for metabolism and production of transition dairy cows. Florida Ruminant Nutrition Symposium Best Western Gateway Grand Gainesville, Florida, USA.

If I suspect ketosis in the herd why not just drench with propylene glycol?

Propylene glycol is also largely fermented in the rumen. This increases acid production and thus can make SARA even more of a problem. Cows with SARA tend to eat less. This leads to greater negative energy balance and more ketosis. It’s a metabolic merry-go-round. With Glycal Forte in the feed you don’t need to drench the cows, and you address three metabolic problems with one product – ketosis, SARA and hypocalcaemia.

Can I make other changes to my rations when I feed Glycal Forte?

Feeding Glycal Forte provides the opportunity to feed more forage, and to remove other ingredients such as fats, calcium soaps, buffers and yeast. Speak to our nutritionists for further advice on ration changes.

Can I feed Glycal Forte to my dry cows?

Cows will benefit from the extra glucogenic energy provided by the bypass glycerol in the 2 to 3 weeks before calving. Let your nutritional advisor know that Glycal Forte has a negative DCAD (about -25meq/100g).