New ways to monitor feed quality

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Forage feeding Feed costs are expected to moderate this year — at least compared to the sky-high figures encountered last year — but it is still vitally important to get the most out of every ounce of feed.

New technologies are available to help producers accomplish this. These technologies really get in there and analyze the feeding value of corn silage and other ingredients — and also spot inconsistencies, such as when a farm begins feeding from a new bunker of corn silage.

“On paper your ration might say a certain percentage of starch is available to the cow. But in reality it might be a completely different percentage,” says Jeff Harris, nutritionist with EPL Feeds in central Washington.

There are a number of traditional lab tests that help. But new technologies take it one step further.

Crude protein analysis on forages and key ingredients has been the normal approach by nutritionists over the years. Fiber measurements, particularly ADF and NDF, provide guidance on intake and digestibility. And, starch values are obtained on corn silage to enhance strategies to maximize energy intake, while also avoiding potential “starch overload.”

However, these approaches overlook the impact of the digestibility of key crude nutrients, points out David Weakley, director of dairy forage research for Calibrate Technologies. 

“For example, higher dietary starch levels can be both safe and desirable if ruminal digestibility of one or more starch sources is low,” Weakley says. “Moreover, high-forage diets can produce very high levels of milk production, despite their lower energy density, if their ruminal NDF digestibility is high, allowing for greater dry matter intake, particularly with higher-producing cows. Therefore, knowing the ruminal digestibility of key nutrients can offer the opportunity to recommend an assortment of diets to meet current economic and ingredient inventory conditions,” he adds.

Here are a couple of case studies that illustrate this concept in action:

Case 1
The following case was handled by Barry Dye, senior dairy consultant with Purina Animal Nutrition, LLC.

A North Carolina mixed breed herd — part Jersey, part Holstein and part Jersey-Holstein cross — expanded from approximately 300 cows in the milking herd to 840.

Even though the expansion involved a new free-stall barn, the owners felt that given the size of the holding pen and other potential bottlenecks, it was best to switch from three-times-a-day milking to 2X.

The switch from 3X to 2X occurred in November 2012. Anytime a switch like that occurs, the farm risks losing some milk production — and, in this case, it wasn’t the outcome the owners wanted. They felt there was still untapped milk production potential in the herd, despite the switch to 2X milking.

So, they challenged nutritional consultant Barry Dye to look at the rations and see if there were some opportunities. Is there more milk in these cows? they asked.

Dye reviewed the rations and they looked OK on paper. Dry matter intake didn’t appear to be a problem, either.

It would require closer inspection.

Dye turned to a forage diagnostic system known as Calibrate. And, the first set of results certainly got his attention. The rumen undegradable NDF score — a measure of undegraded NDF mass in the rumen — was higher than 100 in a couple of the key feeding groups.

That told him two things:

• Dry matter intake may be limited by undegraded feed/rumen fill.

• More degradable starch is needed in the diet.

“When that score is greater than 100,” it indicates that ”if we increase the NDF digestibility or decrease the amount of NDF in the diet, there is a likelihood we can increase dry matter intakes,” Dye says.

More and more evidence came in. Another component of the Calibrate test turned up rumen degradable starch scores that were lower than Dye wanted to see.

Since the farm was already targeting its better forage to the high-producing cows, there wasn’t a lot of opportunity to feed more digestible NDF from the current feed supply. So, Dye cut back some of the forage, which lowered the amount of NDF in the diets.

It’s worked out pretty neat, because some of room that was left in the diet gave us more room to increase the amount of fine-ground corn we were feeding, and that let us raise our ruminally degraded starch scores,” he said.

There was an immediate response. Within a three-week period, the herd average moved from 62 pounds of milk per day to 68. Even with 6 extra pounds of milk, the components remained constant — butterfat at 4.1 percent and protein at 3.15 percent.

Meanwhile, the farm owners “have been extremely satisfied,” Dye says.

And, it turned out that the owners’ intuition was right — the cows did have more milk in them that needed to be utilized.

Bottom-line: Calibrate gave Dye a powerful tool to dig deeper and peer into what was going on in the feed and the rumen

Case 2
Editor’s note: The following case was handled by Wade Steen, dairy nutritionist in Roswell, N.M.

It was baffling: Two herds identical in many ways, owned by the same person, but different in how they handled the introduction of dried distillers grains into the ration.

Each of the herds was 2,500 cows, located in southeast New Mexico.

The herd managers and nutritionist tried including a moderate amount of dried distillers grains — 4.5 pounds on a dry-matter basis — into the ration.

In one herd, the butterfat remained constant following the inclusion of DDGs. But, in the other herd, butterfat dropped dramatically from 3.2 percent to 2.7 percent. This was puzzling, since both herds had the same rations, the same forage base — even the same feed mixer and feed truck.

Intuitively, most people would focus on the DDGs. But, could it be something with the grain? Or starch levels?

Nutritionist Wade Steen already had a good baseline to work from. For four months, he had been testing out a new forage diagnostic system known as Calibrate from Forage Genetics International.

“Calibrate not only allows me to monitor starch level in the ration, but gives me an accurate, predictable estimate of how degradable that starch is in the rumen,” Steen says.

“I knew where the starch levels were (and they did not change following inclusion of DDGs), so I knew it wasn’t starch,” he adds.

He also knew that his forage and digestible NDF levels were adequate.

Digestibility of the forage is a difficult thing to stay on top of since the degradability of corn silage can change during the course of year, even among silage stored in the same pit or bunker silo. But Calibrate allowed Steen to monitor this before and after inclusion of the DDGs.

So, with those other things out of the way, Steen was quickly able to move on to the next rule-out, which was polyunsaturated fatty acid (PUFAs) from the distillers grains. In this case, one of the herds apparently did not react to the introduction of PUFAs as favorably as the other herd. Once the DDGs were removed, the herd’s butterfat came back up within a matter of three to four days. Within 10 days, butterfat was 3.2 percent, which was normal. Herds in New Mexico are generally around 3.2 percent butterfat for much of the year, Steen says.

 

Sidebar: ‘It’s an unbelievable tool’

Fermentrics, a new diagnostic test that measures the digestion rates of feed samples, is generating buzz in the industry.

“I think it’s such a valuable tool for the dairy industry, I’ve been trying to get nutritionists and producers to understand its practical utility,” says Bill Mahanna, global nutritional sciences manager at DuPont Pioneer.

With Fermentrics, an individual feed or TMR sample is placed in a closed vessel with rumen fluid to measure fermentation gas production. The automated system produces 5,000 data points over the 48-hour incubation. Sophisticated curve-peeling software is used to separate the gas curves into a “fast pool” and a “slow pool.” While not completely homogeneous, the fast pool consists mostly of starch and the slow pool consists mostly of fiber. This gives a more accurate picture of digestion kinetics than traditional methods that may only use one or two time points.

Mahanna likens it to charting a runner’s progress in a long-distance race. If the runner’s progress is charted only once — say, at the end of six miles — it gives an indication of his speed.

“What would be a better indicator of his running ability would be to measure his time for each and every mile,” he says. “And, in a way, that is kind of what Fermentrics is — it’s allowing us to measure continuously over the whole fermentation to see the rates of digestion at various time points.”

From the data, a graph is developed from which the carbohydrate digestion rate values are calculated. These values can be used in sophisticated ration-balancing programs rather than relying on book values populating the feed libraries.

The Fermentrics methodology also allows for direct measurement of microbial biomass production, or “how many rumen bugs grow on the sample.” This is a powerful metric that can be used to compare feedstuffs or TMR samples. The Fermentrics report also includes an innovative new approach to measuring soluble protein, which many nutritionists believe provides a more realistic value than the traditional borate-buffer soluble protein method used by most laboratories.

The possible applications of Fermentrics are endless.

• Troubleshooting forage quality. For instance, a nutritionist can order separate analyses of the TMR and the corn silage. If the corn silage comes back high in microbial biomass production and digestion rate, but the TMR is not so good, then it’s something else in the TMR besides corn silage — typically, the legume/grass forages? that’s holding things back.

• Formulating rations. With Fermentrics, you can run an analysis ahead of time and get a good idea of whether the new ration will work. “Theoretically, you could use Fermentrics to put together a couple of different scenarios for rations,” Mahanna says. That might be cheaper over the long run “than trying to wait for the cows to tell us (how a ration is doing),” he adds.

• Benchmarking successful rations. One opportunity often overlooked by nutritionists is sampling the forages or TMR when cows are performing well, and using this as a benchmark to work toward when production falters.

The price of Fermentrics (including all of the traditional analysis values) is $145 for a TMR and $125 for individual ingredients or forages. Mahanna calls it “a very reasonable price for all of the information that is measured by this innovative methodology.”

“It’s an unbelievable tool,” he adds.

Dairyland Labs in Arcadia, Wis., offers Fermentrics in cooperation with

RFS Technologies from Ottawa, Canada.


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