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3 Tips to Evaluate Your Herd’s Dietary Fat Sources

13:33PM Jun 26, 2014

Think you’re getting the same value from different fat sources? Not necessarily.

By Dr. Elliot Block, Research Fellow, Arm & Hammer Animal Nutrition

Supplemental fat, especially in early lactation, supports milk production, helps cows retain body condition and positively influences reproductive performance. Plus, fats contain 2.25 times more energy than starches and digestible fiber found in common grain or forages sources.1

Add in the fact that ration ingredients high in fat content are economical and more available than ever, and it’s easy to understand why supplemental fat feeding has become a common practice for producers seeking to increase ration energy levels and increase milk production.

The challenge is that many dairy producers think they are getting the same value from different fat sources. But that’s not necessarily the case.

Fats Are Not Created Equal
The differences in response to various supplemental fat sources are more profound than almost any other nutritional intervention studied to date. Available research clearly demonstrates that fats aren’t just fats.

For example, a meta-analysis2 published in the June 2012 Journal of Dairy Science and illustrated in Table 1 shows just how much different fat sources impact important milk production parameters.

Table 1. Effect of supplementing different sources to lactating dairy cows.2

Side-by-Side Comparisons

A study3 conducted at the University of Delaware that was presented at the 2013 American Dairy Science Annual Meeting evaluated the long-term effects of two different supplemental dietary fat sources on early-lactation milk production.

The study found:

  • The 12-week trial found that cows fed calcium salts of palmitic fatty acids (MEGALAC® Rumen Bypass Fat) produced significantly more pounds of milk (See Table 2), milk fat and protein than the fatty acid prill. The cows fed calcium salts of palmitic fatty acid also exhibited more persistency of lactation.
  • As a result, cows in this group had improved feed efficiency and Income Over Feed Cost.

Table 2. Increase in Milk Yield

In addition, the study results also indicate that short-term feeding trials or demonstrations are insufficient to evaluate various sources of supplemental fatty acids.

Therefore, the researchers concluded that supplemental fatty acids have differential effects on milk production and the persistency of that production. Also, there is reason to believe based on this study that there is a maximum amount of certain fat sources, like fatty acid prills, that can be utilized effectively in milk and component synthesis.

This knowledge opens the way for ration formulation with supplemental fats to be more effective in the future.

Select Carefully

Meanwhile, here are a few more considerations to keep in mind when selecting a source of supplemental fat.

  • First and foremost, it is important to use products that feature published research and are from reliable sources/suppliers.
  • Also know that rendered or processed fats originate primarily as recovered waste fats and can be highly variable in quality, so be sure to choose a consistent, reliable, proven fat source.
  • Look for supplier certifications, like the Safe Feed/Safe Food Certification Program to ensure that you obtain consistent, quality products.

Lastly, while feeding supplemental fat may have a downward impact on dry matter intake, this tool has a strong positive influence on milk volume and milk fat yield, which increases feed efficiency. Be sure that you are evaluating feed ingredients on the totality of their impact, not just one aspect, and have a plan to monitor animal performance to ensure that you have chosen well.

1 Amaral-Phillips DM, Hemken RW, Jackson JA. Should You be Feeding Fat to Your Dairy Cows? University of Kentucky Cooperative Extension Service. Available at: Accessed: April 28, 2014.
2 Rabiee AR, Breinhild K,Scott W, Golder HM, Block E, Lean IJ. Effect of fat additions to diets of dairy cattle on milk production and components: A meta-analysis and meta-regression. J Dairy Sci 2012;95:3225-3247.
3 Block E, Kung L, Merrill C. Production performance parameters of early lactation dairy cows fed a diet supplemented with MEGALAC or a fatty acid prill containing high levels of palmitic acid. J Dairy Sci 2013;91(E-Suppl. 1):237. Abstract in press and data on file.
4 Ma G, Harrison J, Block E, VanWieringen L. Effect of dietary fat source on milk production and milk composition in early lactation cows in a continuous trial design. J Dairy Sci Abstract in press and data on file.