Nutritionists and dairy producers need a lot of information about forage inputs to formulate a workable ration. Among the most critical is neutral detergent fiber (NDF) analysis. A solid understanding of NDF allows nutritionists and producers to make an economical ration designed to help cows maximize milk and milk component yield while optimizing rumen function and health.

“NDF is really the functional fiber in the forages fed to dairy cows,” noted Anthony Hall, technical services — ruminant with Lallemand Animal Nutrition. “NDF is the basis of the farm-grown forages that lead to the greatest economy and highest milk production in our dairy herds.”

NDF gives dairy producers a measure of the digestibility of the forages on the farm, but it’s actually composed of three separate measurements:

1. NDF digestibility over a period of time (NDFd);

2. The rate of digestibility (kdNDF), and

3. Ballast, or “fill,” of NDF -- undigestible NDF (uNDF or iNDF).

“Taken together, this tells us how digestible the forages are on the farm, how quickly the digestion takes place and what the limitations to digestion might be,” Hall said. “There are quick and economical laboratory analyses available to help producers get these data.”

With this information, producers and nutritionists on some large farms can tweak both lactating and dry cow rations every two or three weeks. Often, these are small adjustments. However, sometimes weather events don’t allow producers to harvest forages at the optimal time, which compromises NDF digestibility.

“In these cases, it may mean we need to feed more grain, but it could be there are other solutions,” Hall said. “More and more producers are turning to probiotic feed additives to improve NDF digestibility in challenging forages or in the whole ration.”

In these cases, producers may consider including an active dry yeast probiotic.

In a meta-analysis of 14 research trials, cows supplemented with an active dry yeast consisting of Saccharomyces cerevisiae CNCM I-1077 showed an increase of 2.1 lb. of 3.5% fat-corrected milk and were more efficient than control cows.

Another way to manage NDFd in forages is by applying a silage inoculant at ensiling. This helps manage the digestibility of the forage before it’s inside the feed bunk. Inoculants also can help prevent production drops by maintaining feed quality and improving the stability of the silage, Hall said.

“We’re understanding NDF in a lot more detail,” Hall said. “Now, we can both complement and supplement our forage base to make sure we’re optimizing rumen function and maximizing milk yield.”