Break down that fiber

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Milk prices are basically out of your control. And, feed prices to a large extent. But there’s one area where you can still gain the upper hand, and that is improving forage quality and utilization.

You need to get the most from your forage. The limiting factor, often times, is the extent of fiber in the forage and how easily it can be broken down. Research has shown that a 1 percent increase in forage fiber digestibility equates to a 0.37-pound increase in dry matter intake and another 0.51-pound increase in daily milk yield.

Traditionally, we have focused on external factors, such as stage of plant maturity, harvest date, cutting height and ensiling management to improve forage quality.

But we also need to look at it internally; that is, what happens inside the cow. A growing body of research shows that yeast supplements can help break down the fiber and utilize the forage more effectively.         

Help the fungi

Inside a cow’s rumen, there are fungal organisms that break the fiber down. Like everything else, they work best in certain environments. Anything you can do to remove oxygen in the rumen and raise the pH will help the fungi.

And, that’s where yeast come into play. Rumen-specific yeast deplete or consume oxygen, leading to an anaerobic (or oxygen-free) environment. And, yeast also promote the growth of lactose-utilizing bacteria, which reduces lactic acid and raises pH, according to Ana Lourenco, associate professor at the University of Tras-os-Montes and Alto Douro in Portugal, who spoke on plant cell wall nutrition at a 2010 symposium held in the Netherlands.

In addition, yeast provide amino acids (mainly thiamine) and vitamins that stimulate the fungi.

Again, there are certain rumen-specific yeasts that accomplish this. Not all yeasts are alike. When considering a yeast additive, be sure to ask for independent research and make sure that the strains used in the research are the same strains you are considering buying. (For more information, please see “Should you use that feed additive?” in the April 2010 issue of Dairy Herd Management.)

Research backs it up

One type of yeast that’s often used in products is Saccharomyces cerevisiae

A group of French researchers looked at different experiments involving Saccharomyces cerevisiae and its effects on ruminant performance. This meta-analysis of over 110 papers and 157 experiments involving different commercial products showed that yeast supplementation increased rumen pH by 0.03 points, on average, and milk yield by approximately 2.2 pounds per cow per day. In addition, improvements were seen in dry matter intake, rumen volatile fatty acid concentration and organic matter digestibility, as reported in the April 2009 edition of the Journal of Dairy Science.

Another meta-analysis looked at one specific live strain of Saccharomyces cerevisiae. After reviewing 14 trials involving 1,615 dairy cows, the researchers found the strain increased milk production by approximately 2.2 pounds per cow per day, on average, with greater than 4.4 pounds when the cows were fed intensive diets with high concentrate levels. It also found a 3 percent improvement in feed efficiency. The meta-analysis was conducted by Mary Beth de Ondarza of the W.H. Miner Agricultural Research Institute in Chazy, N.Y., and Charles Sniffen, former president of the Miner Institute who now has his own nutrition-consulting business. Other independent researchers recorded a 0.3-point increase in pH, and up to 0.5 points when fiber level was low or acidosis risk was high.

In addition, that particular strain has been reviewed by the U.S. Food and Drug Administration regarding improved fiber digestion. Specifically, the strain aids in maintaining cellulolytic bacteria in the rumen of animals when those animals are fed diets containing greater than 50 percent concentrate.

Always check the research behind a particular product.

What does it all mean?

Science aside, the main objective here is to improve fiber digestibility. Making the forages more digestible can improve feed efficiency and milk production. 

Intake in many cows is limited by gut fill. When they take in a certain quantity of forage, their digestive systems must work to break it down and they can reach a point where they don’t want to eat any more. Usually, it is the fiber that is causing this backup, since forage fiber is very filling.

But, as fiber digestibility improves, fewer cows in herd are limited by rumen fiber fill, points out Mike Allen, dairy nutritionist at Michigan State University. And, you can increase the forage content of the diet if the fiber is very digestible. 

That has major implications for dairy producers.

The ability to feed a higher proportion of forage in the diet — relative to concentrates — is important, financially, since many of the concentrates have gone up in price.

One farm may not have enough forage and is using forage fillers or non-forage feedstuffs, like soy hulls, to keep the cows going. Some of those can be expensive. Another farm may have an abundance of forage and wants to know how it can feed more.

Both of those situations can be improved by knowing about fiber digestibility, Sniffin points out.

“If the farmer understands this a little better, and knows it’s important, then he can sit down with his agronomist and nutritionist at the same table and make some decisions as to what forages to grow,” Sniffen says.

At the end of the day for the farmer, it all boils down to putting the right things together, Sniffen adds. Using the right forages and getting the most out of them is bound to help the bottom-line.

And, yeast can play a role in that.


Not all yeast are alike

It’s very difficult to make generalizations about yeast because yeast are different, depending on the species and the strain. 

For instance, there are thousands of strains of Saccharomyces cerevisiae, the type of yeast commonly used in commercial feed additives. One strain can be quite different than another.

They are well aware of this in the beer- and wine-making industries, which also use Saccharomyces cerevisiae organisms. A wine-maker can use the same facilities, the same grapes and so on, but the wine will taste different based on the particular Saccharomyces cerevisiae strain used.

The same thing is true with regard to Saccharomyces cerevisiae used in dairy supplements. Some are better adapted to the rumen environment than others.

Check to see if the strain contained in a product is the same strain that is showing positive results in research trials.

 

 



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Mike Watkins    
Denton TX  |  August, 14, 2012 at 10:01 AM

It is true that not all yeast or yeast products are alike; however, the results in improved rumen function are astonishingly similar. But, I think you will find that it doesn't matter if it is a live yeast product, a yeast culture with Nutrilites or an autolyzed yeast product. Rumen microflora are stimulated and rumen fermentation and cow performance improved. Essential components needed to get a yeast product response are sufficient energy and RDP. The bugs need enough energy and nitrogen (AAs and NH3) to grow their populations and affect feed utilization and subsequently feed intake and lactation. Fiber digestion is a major benefactor in this improved feed utilization as long as rumen pH is properly maintained, which it should be in higher fiber, lower levels of readily fermentable carbohydrates.


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