New research will revolutionise the way we feed calves

14 September 2018

New findings from the Trouw Nutrition LifeStart calf research programme in Holland highlight opportunities to rethink calf milk replacer formulation.  Ruminant Technical Business Manager Georgina Thomas says that rethinking the objectives of calf milk replacers and paying closer attention to the formulation will have significant benefits for calf performance.

The LifeStart programme is a major R&D commitment looking at the development of heifer calves right through until they enter the milking herd. The research is allowing us to develop new evidence based approaches to calf nutrition,” she explains.

Every year a significant proportion of all calves will be fed below their growth potential, having an impact on sustainability and profit.  With pressure on dairy margins and all costs, optimising calf nutrition must be a business priority.

Dr Mike Steele, Assistant Professor of Alberta, Canada, has pointed out that the impact of early life nutrition is one of the most significant advances in dairy nutrition of our time, with the potential to revolutionize attitudes to calf rearing.

The LifeStart project has helped quantify how the management of calves plays a key role in setting lifetime performance. 

Our unique approach is based on harnessing the benefits of metabolic programming to unlock genetic potential.  The research has demonstrated that feeding calves the elevated LifeStart planes of nutrition has a significant impact on gene expression.



Some of the initial findings surrounded how much milk replacer to feed, with benefits from feeding at higher levels.  Georgina says enhanced feed rates promote better growth and also have a direct effect on organ development, gene expression and milk yield in the first lactation.

While many farmers are now looking to feed higher levels of milk replacer, increasing the amount of milk replacer fed is only part of the story.  She says it is also important to consider the quality of the product being used. 


As figure 1 shows, the nutritional requirements of calves change with growth rates.  Many current formulations of milk replacer are not optimised for feeding at higher levels, increasing the risk of over or underfeeding specific nutrients.  She comments that the new research highlights areas where the formulation and presentation of milk replacers can be enhanced to support better calf development and growth on high feed rates.


Figure 1: Effect of daily growth rate on nutrient requirements for calves

We need to look at feeding calves smarter, understanding more about the metabolic pathways in the calf and the impact of a range of factors including concentration, feed rate, feeding method and most importantly the quality of the replacer.

To do this we need to go beyond the headline numbers on the bag.  All milk replacers look and smell fairly similar, but there can be major differences in quality which in turn means they will perform very differently.   

Commercial milk replacers are often compared and evaluated based on declarations on the label.  Discussion rarely delves into what makes up the components of energy, protein and mineral balance and the potential effect on digestion, absorption or growth meaning farmers can’t make a fully informed decision.  Factors such as energy sources, fatty acid composition, protein quality, amino acid: energy balance, trace element and vitamin content, nutrient synchrony and how the replacer s processed will influence how calves will perform and none of these is detailed on the label.


A quality product may cost more but if it delivers better growth and supports health it is a wise investment, and the findings of the LifeStart project mean we can now produce a better quality product which is better designed to meet the calf’s requirements, translating into better performance.

If a quality milk replacer costs £200/tonne more, this will translate into around £2/calf.  Price is not the issue.  The issue is about changing perceptions and explaining the superior ROI of quality products rather than simply comparing the label and the price.



It is important that research is used to develop milk replacer formulations, and to do this we should use whole milk as the biological reference.  If you want a calf to grow well, feed her the product that has evolved to meet their requirements. 

If you look at how a suckled calf is fed, it is fed adlib warm milk, feeding more than 5 times a day and consuming approximately 1.5kgDM/day which is vastly more that the intakes on most calf rearing systems.

Significantly the composition of the milk itself is very different too.  We compared milk replacers with the milk produced by a suckler cow (figure 2).  This is important as a suckler produces what the calf wants, while a dairy cow has been bred for yield which has a dilution effect on milk quality.

Figure 2: Comparison of nutrient content between suckler cow milk and conventional milk replacers

Suckler cow milk is higher fat than milk replacers but with less lactose. Very importantly, both the energy and protein in cow’s milk are far more digestible than those found in widely available milk replacers.

The perceived wisdom in calf rearing is that protein is the first limiting nutrient and the emphasis has been on developing higher protein content milk replacers.


The LifeStart research shows that it is actually energy, and importantly quality of energy sources that become limiting first rather than protein and for this reason we have focussed on both the energy content and the specific energy sources to ensure requirements are met. 

Fat contains twice the energy of carbohydrates, such as lactose, so it is essential that milk replacers have a high fat content, but not all fat is as well used as others.  It is important that the fat is digestible and the fatty acid profile will have a significant effect on overall digestibility.”

The fatty acid profile in milk replacers has a significant impact on energy digestibility and utilisation.  Cow’s milk typically has fewer long chain fatty acids than milk replacers due to the sources of fat included.  Trouw Nutrition have concentrated on achieving the exceptional levels of digestibility seen in milk fat which is 95-97% by using combination of vegetable oils which mimic the fatty acid profile of cows’ milk.  

Digestibility can also be improved by reducing the fat globule size.  In our new manufacturing processes we have developed a process including homogenisation and spray drying when vegetable fats and dairy products are precisely combined with fat encapsulated in a lactose and protein case.  The result is a fat globule one thousandth the original size and the same as the globule size in cow’s milk.

By improving globule size we can improve digestibility, making energy use more efficient.  You also avoid the problems seen when fat particles are too large fat which include poor mixing, coating of buckets and feeding equipment and blocked pipes on automatic feeders, problems many farmers will be familiar with.

While energy is the driver, it is important to feed sufficient protein and to ensure protein quality is high.  In the same way that energy digestibility is crucial, so protein must be highly digestible.  Vegetable proteins are poorly digested by calves (table 1) and in addition can be difficult to mix making skimmed milk a better source for calves.


Table 1: Relative digestibility of different protein sources fed to calves

In addition it is important to ensure sufficient essential amino acids and the LifeStart project highlights the importance of formulating to lysine: methionine and Lysine: Threonine.



One of the other ways in which milk replacers have moved away from cow’s milk and can help explain the increased risk of nutritional scours is osmolality which measures the concentration of soluble particles in a solution.  It adds the concentrations of sugars like lactose which being a large molecule is a major contributor to high osmolality with the concentration of major minerals like sodium and chlorine.

In simple terms, when osmolality is high there is an increased risk of digestive upsets and reduced performance.  The osmolality of cow’s milk is 300-330 while typical calf milk replacers are 400-600.  By comparison sea water is 1000.

Osmolality is important as it influences water exchange in the gut.  A feed with high osmolality will draw more fluid through the gut wall from the blood.  This reduces the gut integrity and increases the risk of scours and other gastrointestinal conditions.  In addition the immune system can be compromised.



The outcome of the Lifestart research has been the specification of high quality milk replacers which represent a paradigm shift in milk replacer formulation.  Energized Calf Milk has been developed using whole milk as a biological reference and is specially formulated to ensure optimal nutrient supply on high feed rate systems.

Combining good energy levels with a balanced fatty acid profile and optimal physical presentation give a product with 10% more metabolisable energy than a typical milk replacer to ensure energy is not limiting, even as the calf’s requirements grow.

The new range of Energised Milk Replacers are based on the results of extensive research, moving the nutritional profile of milk replacer back closer to cow’s milk.  The outcome is an evidence based product differentiated for farmers looking for optimal performance from their calves.

People may be surprised to see a milk replacer with higher fat and less protein but the evidence from our trials and farm studies is that the results in terms of growth rate and performance, delivering an exceptional return on the extra investment.

As one of our customers puts it, If we mix a conventional milk replacer it will be around 2.5% fat while an Energised Calf Milk is 3.75% fat.  For 20 years we have basically feeding calves on low fat milk which makes no sense.  Now we can fed them on full fat which has to be better for the calf.

Our market research shows that farmers are moving to more frequent feeding and increasing the daily quantity fed to boost total intakes.  With energizer milk powders they will be able to ensure they are feeding the appropriate quality too.

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