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Data Distillations is published quarterly and utilizes Rock River Laboratory’s vast database of feedstuff information from across the United States, along with our expert team, to share important insights.

In an effort to help the agriculture industry stay in front of challenges and opportunities with available feedstuffs, relevant graphs will be shared, along with what our team members are gleaning based on those graphs. Prepare for and remedy the ups and downs of feedstuffs components you utilize in your rations with the help of another set of eyes. Sign up to receive alerts when new Data Distillations are available each quarter by completing the thirty-second form at the bottom of this page or click the link here

December 14th, 2022

Author: Katie Raver

Gut Check

A healthy gut is the foundation of an environment that is better able to withstand the impacts of minor to moderate pathogen or toxin issues. However, if the gut becomes compromised feed hygiene issues can arise.. These issues can compound upon themselves, and often when we begin to see clinical illness on a farm, there is not just one culprit, but several contributing factors. Sub-acute rumen acidosis is a known issue of the foregut, however, more recently acidosis in the hindgut has become a frequent topic of discussion. 

High starch levels coupled with poor starch ruminal starch digestibility may lead to increased starch fermentation post-ruminally which may have a negative impact on the gut’s protective mucosal barrier and epithelium. This damage may then create pathways for anti-nutritional factors to wreak havoc on the cow. When digestive upsets present themselves, we often find ourselves scrambling to find the root issue, however, monitoring key “risk factors” over time can help us understand challenges and act quickly to resolve them. This corn season presented many threats  - varying by region. Some experienced a slow dry down leading to late harvest, intermittent drought, or persistent drought in some areas. Meanwhile, other regions saw a wet spring and others experienced late season moisture. With corn silage season wrapped up, we are finally starting to outline the potential risk factors this year’s crop brings to gut health.

Similar to the 2021 corn silage crop,  in-situ starch digestibility in 2022 corn silage may be reduced as compared to previous years. Although fermentation can help combat some of these challenges, producers who are forced to open piles early may be at higher risk for increased starch passing into the small intestine or hindgut. 

Figure 1. 7-hour in-situ starch digestibility over the past 4 years

A Rock River Laboratory data plot of 7-hour in situ starch digestibility over the last 4 years

2019 2020 2021 2022
Mean 77.45% 76.56% 73.47% 73.03%

When evaluating potential feed hygiene challenges in 2023, two things stand out: increasing levels of Vomitoxin (DON) in corn silage and increasing enterobacteria levels in TMR. 

Since September of 2022, 43 percent of corn silage samples tested have been above 1.5 ppm of vomitoxin (DON). Research conducted by Dr. Smith and colleagues at the University of Wisconsin has found that DON can be present in both ears and stalks of corn plants, and DON infection in the stalks may be especially hard to treat with fungicide application. That means, even if corn silage is treated with fungicide, it cannot arbitrarily be assumed to be DON-free. DON is often also used as a barometer for other potential contamination issues in the feed. 

Figure 2. Vomitoxin levels across the US

Plot of Rock River Laboratory database DON levels across the US over the fall of 2022

Although, on average, DON is just approaching a concerning level, due to the high percentage of tests coming back with elevated DON concentration, I recommend keeping an eye on this as time progresses. Research has shown that DON levels can increase after ensiling, so although a crop may test low at one time point, this is not necessarily a static number and may necessitate further testing if issues arise. It’s also important to consider that this trend is not region specific, and we are seeing elevated levels in many different locations across the US (See Figure 3).

Figure 3. DON occurrence across the US

A plot of all Rock River Laboratory database DON occurences on a map of the US

Although not specific to corn silage, there has been a slight increase in enterobacteria levels over the past year. Enterobacteria refer to a class of harmful bacteria that originate from the gut of animals. These include e. coli and salmonella, which can contribute to subclinical or clinical digestive upset alone, or in combination with other anti-nutritional factors. They typically arise when feed has been contaminated with manure or dirt.

Figure 4. Enterobacteria levels across the US

Plot of Rock River Laboratory database Enterobacteria levels across the US over the fall of 2022

Alone, none of these individual feed hygiene factors are overwhelmingly concerning, but combined they have the potential to create issues within the cow. Monitoring potential feed hygiene issues over time can help take the fear out of digestive upsets by keeping risk factors on the radar even when clinical issues are not present. Monitoring key parameters ahead of time also help ensure the gut is in good shape and better equipped to handle feed hygiene challenges that may arise.

October 20th, 2022

Author: John Goeser

Rearview mirror insights as we look to 2022 silage

The 2022 corn crop got in the ground late for much of the US, meaning harvest for silage was delayed relative to the prior few years. Case in point: the 2021 harvest for silage was wrapped by mid-September. Harvest for silage was just getting started at that same time in 2022. As the 2022 silage quality picture has yet to be clarified, it’s pertinent to reflect upon what was observed in the 2021 crop to set a clear focus toward analyzing the 2022 crop.

Corn silage quality is a function of carbohydrate content and digestibility, namely digestible fiber and starch. These fractions make up roughly 80 percent of the energetic value per ton. Both are influenced by seed genetics, growing conditions, agronomic practices, and harvest management. In 2021, harvest timing [as indicated by whole plant moisture] appeared similar relative to prior crop years, as seen in Figure 1. This may be interpreted as the crop was harvested at a similar stage relative to prior years. However, starch content, as see in Figure 2, was numerically greater for 2021. More grain and starch equates to less fiber and generally more energy value per ton - assuming the starch in the grain is digestible. This assumption did not hold true, however, and 2021 netted less digestible starch, as showcased in Figure 3. This fact proved problematic for dairy and beef diets and producers’ pocketbooks as nutritionists needed to increase the concentrate in the diet and feed costs to meet production goals.

Looking now toward the upcoming 2022 corn silage crop feeding, beyond fiber digestibility, pay attention to moisture, starch content, and rumen starch digestibility. This latter nutritional aspect may prove pivotal in defining the 2022 corn silage crop quality. Stay tuned - we’ll have more to come on this. 

Figure 1: Corn silage dry matter for US corn silage samples analyzed by Rock River Laboratory, Inc. for crop years 2019 to 2021.

Graph of US corn silage dry matter levels over years 2019, 2020 and 2021

Figure 2: Corn silage starch for US corn silage samples analyzed by Rock River Laboratory, Inc. for crop years 2019 to 2021.

Graph of US corn silage starch over years 2019, 2020 and 2021

Figure 3: Corn silage in situ rumen starch digestibility (7h, percent of starch) for US corn silage samples analyzed by Rock River Laboratory, Inc. for crop years 2019 to 2021.

Graph of US corn silage in situ rumen starch digestibility (7h) over years 2019, 2020 and 2021

August 24th, 2022

Author: Cliff Ocker

How much does corn silage harvest moisture affect fiber digestibility?

As we begin our 2022 corn silage harvest, there are often a number of questions around management factors to help put up the best crop. Moisture at harvest has a great influence on quality. Harvesting corn silage at the ideal moisture for your storage structure sets up the packing/density of the crop for optimum fermentation - which helps keep feed clean with less chance of molds and yeast infiltration. Hitting the correct moisture at harvest also improves the starch digestibility of the crop, but does it influence fiber digestibility?

To answer this question, I took a peek at the numbers from the 2021 corn silage samples within the Rock River Laboratory database. I reviewed Total Tract NDF Digestibility (TTNDFD), which provides the best comparison for fiber digestibility, as it takes into account four different fiber digestibility values versus looking at just one measurement. Figure 1 below shows the TTNDFD values of all corn silage samples from the 2021 crop that had a dry matter of less than 38 percent in the western, Midwest, and eastern US, is. Figure 2, comparatively, showcases the same regions, but where corn silage samples had greater than 38 percent dry matter.

 Figure 1: 2021 Corn Silage TTNDFD for Samples <38% Dry Matter

Graphed plot of TTNDFD over time for 2021 corn silage samples with dry matter less than 38 percent, as seen in Rock River Laboratory's Database

Figure 2: 2021 Corn Silage TTNDFD for Samples >38% Dry Matter

Graphed plot of TTNDFD over time for 2021 corn silage samples with dry matter greater than 38 percent, as seen in Rock River Laboratory's Database


Note the two to four point difference in TTNDFD between the two graphs, for each region. As the crop matures, lignin tends to increase, which decreases fiber digestibility. As with any crop, as the plant pushes its fruit or seed, the plant nutrients are pushed into the fruit or seed, leaving fewer nutrients in the stalk. Keep in mind that every two to three point change in total ration TTNDFD is equivalent to a pound of milk in dairy diets.

Corn silage is a staple in many diets and a great energy source to help meet the energy requirements of dairy and beef cattle. Obviously, a higher fiber digestibility (TTNDFD) allows the animal to utilize more energy from this forage, maintaining better health and performance.

As corn silage harvest gets underway, keep a close eye on the whole plant moisture level to ensure that you are putting up the best crop possible for your herd. Rock River Laboratory can help by providing moisture/dry matter results from representative field samples sent to the lab, or by using on-farm tools. Contact us for more details.

July 15th, 2022 Insights

Author: Katie Raver

Are you keeping score?

Starch availability is coming up quite frequently this year. Unique environmental conditions created some challenges with starch digestibility, and although this may be out of our control, many corn silage management factors can help improve starch digestibility. 

Kernel processing score (KPS) is a metric to describe the degree to which the grain portion in corn silage is broken up. This is presented as the percent of kernels passing through a 4.75 mm screen. Kernel processing is a critical step in helping the microbes in the rumen gain access, through the tough outer pericarp, into the digestible starch endosperm. This will help maximize potential energy available to the cow from the feed, and in turn help increase potential milk production. The Rock River Laboratory recommended goal for KPS is 76.1%. 

Figure 1. KPS distribution in corn silage for 2018-2021 crop years

Year to Date plot of KPS each year 2018 to 2021 vs. industry goal and Rock RIver Laboratory goal scores

In terms of the 2021 crop year across the US, processing levels were the highest they have been in the past four years. The industry has defined optimum processing as a KPS greater than 70%. Using this metric, more than 50% of samples tested for the 2021 crop year exceeded this goal!

When breaking mean KPS down by region, samples from the western US have the highest KPS on average. Meanwhile, corn silage from the eastern and midwestern US is similar - averaging between 68 and 69% KPS over the past four years. Figure 1 highlights that the average KPS in the eastern and midwestern US is not quite hitting the industry goal, represented by the orange line. This emphasizes some potential room for improvement. The 85th percentile for the West, Midwest, and East are as follows: 80.72%, 78.71% and 77.95%, respectively - showing that the top 15% of samples tested are exceeding the Rock River Laboratory goal. 

Figure 2. Mean KPS scores for Midwestern, Eastern, and Western US over the past 4 years

Plot of KPS scores per region as varied over the years 2018 through 2021

Although we cannot retroactively improve KPS, management planning for the upcoming harvest can help to increase the KPS for future crops. Routinely testing and observing as harvest is occurring will help ensure rollers are set to achieve the desired score. Roller clearance should be set between 2-3 mm to adequately process kernels while not wasting time and fuel. Visual tests in the field during harvest, such as quantifying how many unprocessed kernels are in one quart, can help to make changes quickly. Lab testing should also be performed to capture an accurate KPS and ensure goals are being met. 

March 18, 2022 Insights

Author: John Goeser

Mid-spring fecal starch database still suggests opportunity

For the Northern Hemisphere, corn silage and high moisture corn have been in the silo for six or more months. Based upon available experience and data from years prior, we understand that starch digestibility improves with fermentation. After six months, corn silage and high moisture corn should be feeding closer to their full potential as opposed to freshly harvested corn. However, 2022 has proved different. Starch digestibility is still likely an opportunity for many dairy and beef farms. 

Fecal starch measurement has been a valuable tool - having learned from Dr. Ferguson and Dr. Hutjens over the past decades that more grain and starch in manure equates to less digested grain by dairy and beef cattle. The goals for dairy and beef fecal starch levels are less than 1 percent and 3 percent of manure dry matter (DM), respectively. These goals correspond to the top 15 percent of samples analyzed by Rock River Laboratory, Inc. 

This year, many dairy farms still appear to be well above 1 percent,  as visualized in Figure 1. The green line indicates the goal at 1 percent of DM, and some dairies appear to hit the goal. However, the orange line indicates 3 percent of DM, which has historically been considered the benchmark. If we use the Fecal Starch Calculator app available from Rock River Laboratory, assuming 55 pounds DMintake, 25 percent dietary starch, and evaluating the economic difference between three percent and one percent fecal starch at $7.50 per bushel corn, we can recognize the improved total tract starch digestibility at one percent fecal starch equates to roughly $0.07 per cow in wasted feed cost via undigested corn grain. 

Beyond silage and high moisture corn, dry shelled corn is also likely a contributing factor to higher fecal starch levels this year, with the 2021 crop yielding harder and less digestible corn. If dairy or feedyard performance is thought to be suboptimal, consider investigating how much starch is contributing to the challenge by making fecal starch measures for your greater intake pens. With the current feed prices, the economic ramifications of suboptimal starch digestion are greater than ever.

Figure 1: Recent dairy fecal starch results, % of DM, for samples analyzed by Rock River Laboratory, Inc.

Graph of fecal starch percentages over time from March through April 2022

February 23, 2022 Insights

Author: Cliff Ocker

Forage Isn't the Only Source of Variation in the Diet 

Still using book values for commodities? Think again. As nutritionists, we try to do a pretty decent job of monitoring the forage changes on the farm. Often, we sample the new forage from a new crop year, or when we open a new bunker and we pull samples as the cows indicate that something may have changed. Yet, how often do we pull samples of the commodities that are being fed at the farm? Do we think they are always as book values suggest?

As we know, forages test differently from year to year based on a number of factors, including hybrid, maturity at harvest, and environmental conditions. Similarly, our commodities are derived from the same or similar crops and are also affected by some of these same factors and go through additional processing to become the ingredient that we feed on farm. Thus, our commodities tend to be just as variable as forages, and exclusive use of book values may be missed opportunity in terms of profitability on the farm.

Consider this: if the Dry Matter (DM) and Crude Protein (CP) are both two percentage points higher than book values on Soybean Meal (SBM), what does that mean at the farm level in both amount fed and profitability? If two pounds of protein are needed in the diet, from SBM, and DM = 90 percent and CP=46.5 percent, the amount fed/head/day would be 4.3 pounds as fed. Whereas if the SBM is 92 percent DM and 48.5 percent CP, the amount fed drops to 4.12 pounds as fed - a difference of .18 pounds/cow/day. This doesn’t sound huge but with the cost SBM, this is likely over 4 cents/cow/day on a single ingredient!  What if the same is true on two or three other commodities being fed? This could quickly become a 10 to 15 cent/cow/day savings opportunity.  What if the values are lower instead of higher and now there is also lost milk based on a shortage of nutrients?

While our book values suggest that most of our commodities are 88 percent DM, very few dry commodities in the Rock River Laboratory database are less than 90 percent DM, as noted in Figure 1 for DM on Canola Meal (CM). Note in Figure 2, the protein value changes in Canola year-over-year and the variation that we see in SBM for protein in Figure 3.  This type of variation can be seen on most commodities coming through the lab, making it especially important to monitor commodity variation. Adjusting for these variations, in commodities as well as forages, can improve profitability and productivity.

Figure 1: Figure 1: DM variation in Canola Meal over the past 3 years

Graph of dry matter variation in Canola Meal (CM) over the past 3 years from Rock River Laboratory's database

Figure 2: CP variation in Canola Meal over the past 3 years

Graph of Crude Protein (CP) variation in Canola Meal (CM) over the past 3 years according to Rock River Laboratory's database

Figure 3:  CP variation in SBM over the last 3 years

Graph of Crude Protein (CP) variation in Soybean Meal (SBM) over the last three years, according to Rock River Laboratory's database


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