By Jamie-leigh DOUGLAS
Ruminant Technical Sales Manager at Techna Nutrition UK and Ireland Ltd.
Energy is one of the most critical nutrient requirements for ruminants, especially dairy cows, where it represents one of the most limiting factors in dairy diets. Energy plays a fundamental role in the synthesis of milk components such as fat, protein, and lactose. Therefore, ensuring cows efficiently utilise energy is vital for their optimal performance, profitability, and for reducing their environmental footprint. The more efficient a cow is at converting energy from feed into energy for milk production, the lower the feed costs and environmental impact. An energy-deficient diet significantly reduces both milk yield and milk solids production.
What Drives Energy Utilisation and Efficiency in Dairy Cows?
Dairy cows derive their energy from their diet, primarily composed of carbohydrates, which typically make up 60–70% of the cow’s intake. The main source of energy for cows comes from volatile fatty acids (VFAs) produced by the microbes in their rumen. The three key VFAs—acetate, butyrate, and propionate—are responsible for providing 50% to 85% of the cow’s metabolizable energy.
The Role of Volatile Fatty Acids
The balance of VFAs significantly impacts energy efficiency. For example:
- Acetate: Mostly contributes to milk fat synthesis.
- Butyrate: Provides energy through c4-c16 molecules and supports rumen wall health.
- Propionate: The most energy-efficient VFA as it acts as a precursor to glucose, essential for both energy utilisation and milk production through lactose.
VFAs result from the fermentation of carbohydrates, including sugars, starch, and fibre. However, the balance of these components is crucial to maintaining rumen health and ensuring efficient energy utilisation.
- Sugars and quick-starch are rapidly broken down in the rumen, producing VFAs quickly. While these can help increase energy availability, too much starch can lead to rapid fermentation, lactic acid build-up, and rumen acidosis, and therefore having a negative effect on energy efficiency and overall rumen stability.
- Fibre, is broken down more slowly and steadily, providing a sustained release of VFAs.
Balancing the diet is essential. Too much starch can lead to an unstable rumen environment, while too little reduces microbial activity, negatively impacting both digestion and energy efficiency. Additionally, excessive fat intake can suppress appetite and alter milk composition.
Propionate: The Key to Efficient Energy Utilisation

Among the VFAs, propionate stands out as the most energy-efficient. It acts as a glucose precursor and plays a pivotal role in converting energy from feed into milk. By promoting the production of propionate, energy utilisation can be maximised, leading to more efficient milk production.
The Role of the Small Intestine
Not all carbohydrates are fermented in the rumen. A portion escapes fermentation and flows into the small intestine, where it contributes to energy through nutrient digestion and absorption. For instance, starch that avoids rumen digestion is broken down and absorbed in the small intestine, providing glucose directly to the cow.
The small intestine is also the absorption centre for many nutrients. The intestinal crypts in particular are the site of intense nutrient absorption. Increasing the capacity of absorption is also a way to improve efficiency.

Improving Energy Efficiency in Dairy Cows
Energy efficiency can be improved by selecting the right raw materials and by balance of the diet. The quality of the feed impacts digestibility and availability of nutrients. The harder her digestive tract must work to extract the nutrient value from the feed the less energy efficient it is. The quality of the feed also impacts the proportions of the different VFA’s produced in the rumen and this alters the precursors for fat synthesis.
One of the most effective strategies to improve energy efficiency in dairy cows is to shift rumen fermentation towards producing more propionate and less acetate. This can be achieved by selecting the right balance of raw materials in the cow’s diet.
- Starch degradability: Choosing feed ingredients that increase propionate production in the rumen, such as degradable starch, can improve energy efficiency. However, care must be taken to avoid overloading the rumen with rapidly fermentable carbohydrates, which can lead to acidosis and negatively impact energy efficiency.
- Feed additives: The use of feed additives, such as encapsulated essential oils, can help modulate rumen fermentation and enhance energy utilisation.
Essential Oils: A Natural Solution for Energy Efficiency
One innovative approach to improving energy efficiency in dairy cows is through the use of essential oils. ELENSIS, a blend of 100% natural essential oils, has been developed specifically to improve energy efficiency in ruminants. These essential oils have been carefully selected for their synergistic action in the rumen and hindgut.
The product works by shifting fermentation in the rumen towards producing more propionic acid, the most efficient VFA for energy utilisation. Moreover, the product is coated with slow- and fast-release mechanisms, ensuring sustained activity in the rumen and allowing it to bypass the rumen and act in the hindgut. This approach enhances total starch digestibility and improves nutrient absorption in the small intestine, ensuring that more energy from the feed is converted into usable energy for the cow.
It is a way to bring a secure form of energy to the Dairy cow!
A Sustainable Approach to Feeding Dairy Cows
When formulating dairy cow diets, it is important to consider not only digestibility and nutrient bioavailability but also cost-effectiveness and environmental sustainability. Essential oils, like ELENSIS, offer a natural and cost-effective solution that is not subject to price volatility like some other feed additives. However, whatever strategy is chosen, the key is to ensure that the energy provided in the diet is efficiently utilised to meet the cow’s needs while maintaining a stable and healthy rumen environment.
Conclusion Energy is a cornerstone of dairy cow nutrition, playing a crucial role in milk production. Efficient energy utilisation can lead to improved milk yields, reduced feed costs, and minimised environmental impact. By selecting the right feed components, managing the balance of VFAs, and incorporating natural feed additives like essential oils, dairy farmers can optimise the energy efficiency of their cows for better performance and profitability.