Applying new research findings on fat supplementation of dairy diets provides producers with opportunities to optimise cow performance.

New research on the impact of individual fatty acids on cow performance shows there is a lot to be gained by no longer viewing fat simply as a concentrated source of energy.

Instead, understanding the fatty acids that make up fat supplements and how they affect responses and partitioning of nutrients, can enable dairy producers to improve specific areas of herd performance such as milk yield, milk fat content, body condition score and fertility.

According to Dr Richard Kirkland, global technical manager for Volac Wilmar Feed Ingredients, there are seven considerations dairy producers should have when selecting fat supplements:

1. Think about fatty acids – not fat

There are five major fatty acids found in ruminant diets, and each is utilised differently within the animal. Recent research has centred on C16:0 (palmitic) and C18:1 (oleic) fatty acids and their impacts on cow performance during specific stages of the lactation cycle.

C18:1 improves digestibility of total diet fat which increases energy supply.

It also increases the hormone insulin which aids partitioning of nutrients to improve body condition – making it particularly beneficial when offered in early lactation. This fatty acid has also been proven to boost fertility by promoting egg and embryo development.

In contrast, C16:0 increases the partitioning of nutrients to milk, particularly milk fat production. This may be more beneficial in mid to late lactation when a cow is no longer losing body condition but indicates care should be taken with supplementation during the fresh period.

2. Fat supplementation is beneficial in early lactation

Through early lactation when body fat is being used to supply energy, fat supplementation needs to be considered in the context of the impact specific fatty acids have on cow performance.

Researchers at Michigan State University, USA, reported that fresh cows offered Mega-Max, a rumen-protected fat supplement containing a 60:30 ratio of C16:0 to C18:1 for the first 24 days of lactation, produced notable increases in milk fat (+0.33%) and yield, resulting in 2.8 kg/day more energy-corrected milk than the control group of cows. Importantly, these improvements were achieved at similar body condition scores.

“This study demonstrated that where the most appropriate supplement based on the ratio of fatty acids is offered, milk production can be improved without detriment to body condition,” says Dr Kirkland. “Again, this comes down to the impact of individual fatty acids at different stages of lactation.”

3. Early fat supplementation benefits later in lactation

In the Michigan State study, cows supplemented with fat from calving through to day 67 of lactation produced an additional 5.1litres additional milk per day, with +0.2% higher milk fat.

However, in the group where fat supplementation stopped at day 24, cows continued to produce more milk, an additional 2.2litres/day, until the end of the study at day 67, indicating a strong carry-over effect from supplementation in the very early stages of lactation.

“While more research is needed in this area, these findings tell us that what we do in early lactation can have a carryover effect with a pronounced impact on lactation performance. So, when we think about the cost of supplementation, we need to consider that a considered investment made in fresh cow nutrition may continue to pay off later in lactation,” explains Dr Kirkland.

4. Fatty acids must be rumen-protected

To see the benefit of individual fatty acids, rumen-protected fats that have been manufactured to avoid interference with fibre digestion in the rumen must be used.

If unprotected (e.g. vegetable oils or high-oil ingredients such as brewer’s grains), fat will kill many of the fibre-digesting rumen bacterial species and reduce fibre digestion.

“Rumen-protection is critical to avoid reductions in rumen fibre digestibility and to ensure delivery of unsaturated fatty acids, such as C18:1, through the rumen to the small intestine for absorption,” says Dr Kirkland. “We are protecting the rumen from the fatty acids, avoiding reductions in fibre digestibility, while also protecting the fatty acids from the rumen to avoid biohydrogenation of unsaturated fatty acids to ensure they pass to the small intestine for functional benefit.”

5. When it comes to the granule size of fat supplements, size matters

Research by Volac Wilmar Feed Ingredients at the National University of Singapore has reported significantly higher breakdown of calcium salts of ‘fine’ granules (<0.5 mm diameter) compared to that of larger granules (3-4 mm diameter) across a range of different acid conditions to reflect typical rumen pH values.

As the industry-standard method of delivering C18:1 and C16:0 fatty acids to dairy cows, the physical nature of calcium salt-type fat supplements indicates that granule size has a major impact on the degree of rumen-protection of these products.

“While granule size is going to have an impact on the return on investment through fat supplementation, it is important to note that particle size varies greatly according to the manufacturing process,” explains Dr Kirkland. “The Megalac calcium salt brand, manufactured to have a higher proportion of larger granules, is an effective way to optimise cow performance by improving key fatty acid supply.”

6. Decisions should be driven by your objectives

While fat will continue to provide an essential energy supply to dairy cows, how producers utilise it to manipulate performance on a farm level should be determined on individual milk contracts and business objectives.

“Fat has the highest energy density of any ingredient — more than 2.5 times the energy concentration of cereal sources and doesn’t add to the acid load in the rumen. Replacing carbohydrate sources of energy with fat also reduces the production of methane, a potent greenhouse gas,” says Dr Kirkland.

7. Palm oil is an important source of C16:0 and C18:1 fatty acids – selecting sustainable palm is vital

In general, different vegetable oils predominate in one particular fatty acid, with palm being the only prime source for palmitic acid, though also containing significant levels of C18:1 fatty acids.

Ensuring palm oil has been grown and sourced sustainably is key and policies assuring no deforestation, no development on peat and no exploitation of people and local communities should be a fundamental requirement (the often-referred to NDPE policies).

Certification of material by the Roundtable on Sustainable Palm Oil (RSPO) helps drive sustainability in the palm oil chain, enabling the supply of palm accredited to standards including Mass Balance and Segregated.

More than 40% of the world’s vegetable oil production comes from palm, despite only accounting for 7.4% of land devoted to vegetable oil crops. Furthermore, a large proportion of this is grown by smallholders where the crop is essential in providing access to basic requirements for food, electricity, education and healthcare.

“RSPO works directly with growers to improve production practices – while certifying sustainability standards are met throughout the supply chain.

“Since palm oil derivatives are a base for most of our feed fat products, these sustainability policies are essential to Volac Wilmar Feed Ingredients so we can continue to supply farmers with the tools to drive efficiency on their farms without jeopardizing the environment,” says Dr Kirkland.

“By understanding the impact of specific fatty acids at different stages of lactation, fat supplementation can be used to optimise herd performance while also serving as an essential and dense energy source.”