Understanding Fat Sources in Dairy Nutrition
Proper feeding of fat and fat products to dairy cows is a common strategy to boost production; however, understanding the roles of various fat components is essential. Overfeeding the recommended 5% total dietary fat can have disastrous effects on production. Not to mention specialty fat products can be an expensive ingredient. It is critical to understand the role the different sources of fat play in the dairy ration.
There are three types of fat in a dairy diet:
First, some ingredients inherently contain fat – what’s already there. These ingredients are energy-dense and typically come from processed oilseeds. ExPress® soymeal is an energy-dense ingredient that can be fed in a ration. These naturally occurring fats are embedded within the structure of the seed and are released gradually during digestion, providing a steady and rumen‑friendly source of energy. Because they come from whole or minimally processed plant materials, they also supply important nutrients such as fiber, protein, vitamins, and essential fatty acids that support microbial activity, rumen stability, and overall cow health.
Second, there are isolated fats or oils added to the diet called secondary fats. They include ingredients like soybean oil and animal tallow. It is important to note that secondary fats should be limited to prevent milk-fat depression and acidosis. These fats are highly concentrated energy sources because they have been extracted, refined, or rendered, making them rapidly available once consumed. When fed at excessive levels, secondary fats can disrupt normal rumen biohydrogenation pathways, leading to milk‑fat depression, lower butterfat, and reduced feed efficiency. For this reason, they must be carefully balanced and used strategically within the ration.
Third, there are bypass fat ingredients – or rumen-protected fats – that can be supplemented in the ration. Bypass fats are designed to resist breakdown in the rumen so they can pass into the small intestine for direct absorption, providing a clean, efficient energy source without disturbing rumen fermentation. While it is necessary to utilize fat sources as energy for the cow, the quality of the fat source should be considered.
The 100-year review in the Journal of Dairy Science discusses how feeding high-quality fat ingredients can boost rumen functionality and have other positive health impacts, such as improved reproductive efficiency and increased milk production.
When oilseeds are processed using high-shear dry extrusion and mechanical oil pressing – ExPress® system – the quality of the fat is preserved. This includes essential fatty acids and naturally occurring antioxidants. Improved animal performance is the biggest advantage of feeding high-quality fats. When fed ExPress® soymeal compared to commodity soybean meal, dairy cows’ dry matter intake and milk production improved by 2.65 lbs./cow/day (1.2 kg/d) and 7.5 lbs./cow/day (3.4 kg/d), respectively.
