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Mining the Bacterial Genome


Mining the Bacterial Genome

By Bill Ramsey, MS, DuPont Pioneer Livestock Information Manager

Livestock producers fully understand the benefits derived from applying genetic selection decisions in both cattle and corn. The tremendous improvements in milk and meat production and corn yield would not have been possible without a strong focus on selecting superior genetics. However, livestock producers may not be quite as appreciative of the importance of mining the bacterial genome as much as their food science colleagues who use selected bacterial strains to make things like cheese.

When we look at the technological advances that have directly impacted forage production efficiency — from plant genetics to harvest equipment — advances in understanding and manipulating silage microbiology often are overlooked. But these, in fact, may be among the most innovative. In the last 30 years, advances in understanding and mining the genetic potential of the silage bacterial genome microbiology have yielded forage additives which help:

  • Reduce silage pH and conserve sugars
  • Reduce heating on increasingly large silage faces
  • Reduce dry matter loss (shrink), whose energy value must be replaced with very expensive grain sources
  • Dramatically reduce heating and palatability issues, thanks to the introduction of forage additives containing Lactobacillus buchneri strains

One challenge with silage and high-moisture corn products containing L. buchneri is that bacterial species prefer a low pH environment before they begin to grow and then they tend to grow at a relatively slow rate. This means the benefits of reduced heating and improved bunk life can take up to one to two months before being fully manifested. However, by mining vast collections of L. buchneri strains, new products are emerging on the market that confer these benefits much more rapidly — within days rather than months. Thus, the advantage of this is that producers who lack inventory reserves and may have to immediately feed “new-crop” silage will have silage that will stay fresh in the storage structure and in the feed bunk.

Traditionally, it was thought that fermented feeds provided a method of stable storage but due to   the fermentation process, they often were fed with a lower nutritional value than the day they were ensiled. The future of manipulating silage with the addition of bacterial organisms lies in making silage more digestible than the day the crop is harvested. This is similar to how the physical processing of corn silage kernels can improve starch digestibility.

Fiber digestibility is another improvement to silage feed value that has been explored. Research shows that adding certain enzymes to the ration at feedout can improve fiber digestibility. The problem with adding them at that point is that production of those enzymes in a commercial plant results in a high cost to producers.

Another avenue that has been explored is using forage additives that contain traditional fermentation bacterial strains and enzymes. They have never been shown to improve digestibility beyond additives containing bacteria alone. The reason is the level of purified enzymes needed to accomplish fiber digestibility improvement is not financially practical.

One example of mining the bacterial genome that has been successful involves treating crops at harvest with bacterial strains, which in turn produce enzymes as they grow in the silage. Bacterial strains have been selected for the production of specific enzymes that can improve the rate of fiber digestibility when the silage is eventually presented to rumen bacteria. The advantage of isolating a bacterial strain resistant to low pH and producing a fiber-digesting enzyme while growing in the silage is that you essentially cut out the “middle man” and allow the bunker/pile/bag to become the enzyme-yielding fermentation facility.

The future of mining the silage microbial genome lies in making products that can be used as management tools to improve nutritive value rather than insurance policies that reduce potential losses. As the silage industry evolves, nutritionists must fully understand products’ mode of action, because ration formulas may need to be altered to fully realize the value of these products.

When one thinks back on the technological advances that have directly impacted forage, there have been improvements in forage genetics and the equipment industry that have delivered significant gains in harvest efficiency. But new developments in the forage additive industry may be among the most innovative.

Talk to your local team of sales representatives plus your nutritionist and veterinarian to determine the products that are best suited to your operation.

This article was originally published in the Nov. 17, 2015 issue of Progressive Forage Grower newsletter, and is reproduced with permission.

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The foregoing is provided for informational purposes only. Please consult with your nutritionist or veterinarian for suggestions specific to your operation. Product performance is variable and subject to a variety of environmental, disease, and pest pressures. Individual results may vary.