Fresian cows grazing in a field

When it comes to calcium salt fat supplements, size matters

Research by Volac Wilmar Feed Ingredients at the National University of Singapore has shown granule size has a major impact on the rumen protection of calcium salt fat supplements.

The Mole Valley Farmers’ Newsletter Team takes a look. While it may not look like a problem for a calcium salt fat supplement to have a fine consistency, data indicates granule size significantly impacts the rumen protection of these products.

Research at the National University of Singapore has found up to double the breakdown of calcium salts in fine granules (<0.5mm diameter) compared to that of large granules (3-4mm diameter) at typical rumen pH values.

Calcium salts are an industry-standard method of delivering C18:1 (oleic) and C16:0 (palmitic) fatty acids to dairy cows. These findings mean the physical nature of calcium salt supplements is a key factor in the success of delivery of fatty acids through the rumen in the active form.

“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,” said Dr Richard Kirkland, Global Technical Manager for Volac Wilmar Feed Ingredients.

“However, granule size varies greatly according to the manufacturing process and different brands display a large range in granule size. To optimise cow performance and return on investment through fat supplementation, product granule size needs to be considered.”

Feeding calcium salts

Based on where a dairy cow is in her lactation cycle and milk contract targets, different fatty acids support different areas of performance, including milk yield, milk fat production, body condition score and fertility.

“For year-round calving herds, it is unfeasible to target specific fatty acid requirements for individual cows. However, a multi-purpose fat supplement like Mega-Fat Multi, that has a balanced ratio of C16:0 and C18:1, is an effective way to support performance for the entire herd,” added Dr Kirkland.

When balanced correctly, these two fatty acids partition energy into milk production and body condition during early lactation.

According to Dr Kirkland, rumen protected fat supplementation is especially important at turnout to mitigate butterfat depression. “Early spring grass growth tends to be high in sugar and low in fibre. This high sugar content makes it more rapidly fermentable in the rumen leading to the generation of acid. Combined with the lower fibre levels, early grass can compromise rumen pH and increase the risk of acidosis and milk fat depression,” he said.

While feeding a high fibre ingredient like straw will slow down digestion and reduce the risk of acidosis, filling the rumen with low-quality feed bulk will reduce total energy intake. However, feeding a dense energy source like fat will save space in the diet, allowing for the addition of a high fibre ingredient which will help meet energy requirements while simultaneously improving rumen function.

Dr Kirkland concluded: “since rumen protected fat supplementation helps meet energy requirements and supports specific areas of performance, they are the ideal solution for producers working to protect milk production this spring”. “But remember, not all fatty acids will support cow performance the same and not all fat supplements will be equally digested. The particle size of calcium salts matters and clearly, bigger is better”.