Get More from High Forage Diets by Increasing Fiber Digestion

Get More from High Forage Diets by Increasing Fiber Digestion
7/11/2017

Accounting for the grain portion of the corn silage in the ration is critical to ensuring cows respond as intended.

“Kernel processors crack corn kernels during harvest to help improve starch digestibility. When you think about corn silage, it’s really like kernel processed high-moisture shell corn (kp HMSC) on a corn stover stick,” says Anthony Hall, MSc MSB, PAS, Technical Services – Ruminant, with Lallemand Animal Nutrition. “Some rations may appear to be high-forage rations on paper, but the corn silage fraction can contain around 40 percent dry matter as kp HMSC. The hidden kp HMSC can mean the ration may, in fact, be more than half grain. That puts the rumen at risk for disruption.”

High-forage, lactating cow rations are typically defined as those containing more than 55 percent forage in the total mixed ration (TMR), or more than 25 percent forage-neutral detergent fiber (NDF) on a dry matter (DM) basis. It is common practice for today’s TMRs to contain two-thirds of their forage DM from corn silage.

On a whole plant corn silage DM basis, corn silage with 30 percent starch content typically contains 40 to 45 percent of kernel-processed corn grain and 55 to 60 percent chopped corn stover.1 Every one pound of good quality corn silage DM is equivalent to 0.4 pounds of kp HMSC plus 0.6 pounds of corn plant stover DM.

“It’s a mistake to think such ‘high-forage’ rations will not expose the lactating herd to sub acute ruminal acidosis, or SARA,” Hall says. “When SARA occurs, the rumen isn’t optimized and can’t make the best use of feedstuffs, no matter what they are. Even in-feed buffers can’t eliminate the risk of SARA.”2,3

It’s estimated that SARA can cost $1.12 per cow daily — even more if there are additional health or fertility costs.3,4 With these costs, it pays to use feeding strategies to monitor and adjust the ration as needed, including:

  • Monitoring DM content in ensiled forages, moist grains and moist feedstuffs every week
  • Testing for total starch content, starch digestibility and the starch degradation rate on ensiled corn silage and HMSC every month
  • Monitoring NDF and physically effective-NDF content of the TMR
  • Including a rumen-specific active dry yeast probiotic

Adding an active dry yeast (ADY) probiotic — like Saccharomyces cerevisiae CNCM I-1077 — can improve rumen function and increase fiber digestion for all life stages of cattle, Hall notes.

“ADY probiotics that include the strain Saccharomyces cerevisiae CNCM I-1077 have a high capacity to increase pH and fiber digestibility in the rumen,” Hall notes. “Probiotic feed additives can help improve rumen function and increase fiber digestion. Ensuring rumen function is optimized can avoid nutritional issues like SARA and help cattle get the most of any ration.”

Article is published by Lallemand Animal Nutrition, July 2017

Tags: Feeding Strategies, Forages