Margaret Winsryg is a technical support specialist with Calibrate® Technology. Margaret holds a Bachelor’s Degree in animal health science, a Master’s Degree in ruminant nutrition from the University of Arizona, and a Ph.D. in animal science nutrition from Utah State University.
Harvest delays hurt fiber digestibility
Oct 04, 2013
Many dairy producers and nutritionists are looking to higher forage diets to help them reduce feed costs. Lactating-cow diets that previously contained 45 to 50 percent forage are now being formulated to contain 60 percent or more forage.
To accommodate this shift to a higher forage diet, you may be tempted to delay forage harvest to increase tonnage per acre. Although more forage will be available, the maturity of that forage also will be greater. As forage maturity advances, neutral detergent fiber (NDF) digestibility decreases. If forages make up a significant portion of the diet, the lower NDF digestibility could depress feed intake by slowing the rate of passage.
Conversely, a cow consuming a diet with higher NDF digestibility will have lower rumen "fill" or undigested NDF. Less rumen fill means there is a higher rate of passage of feed ingredients through the rumen and this supports higher dry matter intake.
Digestibility testing gives you a better understanding of NDF digestibility in the rumen. You can put this data to use to optimize dry matter intakes, feed efficiency and milk production.
Ultimately, you must balance the advantage of increased tonnage with your farm’s milk production goals. Make a plan for the forages you intend to grow and how harvest dates will impact the digestibility of NDF in those forages when it comes time to feed them to the cows.
Many dairy producers and nutritionists want to feed more forages in order to reduce feed costs. If you choose to go this route, use the knowledge gained from NDF digestibility testing to optimize fiber in your rations.