While it may seem like no cause for concern for a fat supplement to have a dusty consistency, ongoing research indicates that granule size has a major impact on the degree of rumen-protection of these products.

Rumen-protection is critical to avoid reductions in rumen fibre digestibility and to ensure delivery of unsaturated fatty acids, such as C18:1 (oleic acid), through the rumen to the small intestine for absorption. Particle size varies greatly according to manufacturing process and different brands display a large range in granule size.

Ongoing research at the National University of Singapore has indicated up to double the breakdown of calcium salts in fine granules (<0.5 mm diameter) compared to that of large granules (3-4 mm diameter) at typical rumen pH values. Because calcium salts are an industry standard method of delivering this fatty acid to dairy cows, the implications of these findings are clear – the physical nature of calcium salt supplements is a key factor in success of delivery of fatty acids through the rumen in the active form.

Data from Prof. Adam Lock at Michigan State University has demonstrated the unique effect of C18:1 on partitioning of energy in dairy cows, leading to improved body condition scores. C18:1 is also known to improve total diet fat digestibility and improve egg quality with direct beneficial effects to herd fertility. 

Calcium salts are typically a blend of C18:1 and C16:0 (palmitic) fatty acids, the latter having a well-established effect on milk fat percentage. Our current recommendations, based on the US data, centre around a calcium salt product in early lactation being most-appropriate to supply that vital C18:1 fatty acid to boost body condition and fertility, while high-C16:0 products are more applicable in the post-peak period to drive nutrients toward milk fat production for milk fat and milk yield benefits.

Thinking of a fat supplement this winter? Determine the fatty acid profile most suitable for your needs on-farm as well as the product source – when it comes to calcium salts, bigger is better!