Well, this saga gained substance at the 2023 World Dairy Expo (WDE) while looking at the prize winners at the Forage Analysis Superbowl (FASB). Since Forage Innovations clients make up a fair percentage of the finalists, it is a yearly ritual to look over “ours” and “theirs!”
The samples are judged in two ways. First and most obvious, is the feed sample report. Dr. Dan Undersander, UW-Madison Agronomy Professor Emeritus, put together a ranking system using these test results. Not every metric is used, but he has put together the official ranking system. The supervision of the competition is now directed by Doug Harland of Dairyland Labs, Inc., De Pere, WI, and a committee appointed by the WDE. With tweaks to the system as new forage tests have evolved through the forty years of its competition’s existence, the sample comparisons remain relevant. The analysis part of the final score is 70 percent of the final score..
The second part of the final score is a visual analysis. After the entry deadline is reached and before WDE, the samples are brought out of the freezers at Dairyland Labs and arranged in categories with only a number as an ID. The tables fill much of the parking lot of their De Pere facility. UW Extension Educators with “extensive” forage experience, examine the samples. The judges know nothing about the samples
’ origin they are examining except its category.
Visually, the judges are looking for signs the sample could have been doctored, but more importantly, they are looking for quality and anti-quality factors which might affect the sample’s feeding value. A big part of this has to be forage particle size as we nutritionists all have used the Penn State particle separator (PSPS) box as a part of our physical exercise routine for years.
Often scores are remarkably close among the top ten forages in any of the categories and examining many of our Forage Innovation (FI) clients’ entries, it was notable that often the judge’s visual score was lower than the visual score of some of our competitors right above or below in the rankings. Of course, since the visual score is 30% of the total score and when the final contest score could be separated by mere hundredths of a point, the visual score can be very impactful on the total final score.
The obvious difference in FI samples and some with a higher visual score was forage particle length (FPL). And also obvious is the fact that if the visual score is lower than samples above or below, to rank where they did—the FI clients’ feed sample was even better compared to the feed sample report of the competitor!
So, How Important is Forage Particle Length?
Of course, FPL is important, but is it monolithic? Particle length standards have been established and almost universally accepted for many years. A certain length was thought to be needed to encourage cud-chewing, rumination, the maintenance of an adequate rumen mat, and by extension—rumen health. All well and good. However, there are now many top-notch dairy people looking at high-forage diets and dairy efficiency (DE) as metrics for their profitability.
At Forage Innovations (and probably in most of the industry), we feel a high-forage diet is when the forages are at least 60% of the diet or higher. When high-forage diets and DE are important, a cow cannot spend too much time eating her ration at the feed bunk rather than lying at her stall and ruminating. We, obviously, like to make the FASB judges happy, however our clients’ high-forage diets come first! It turns out if FPLs when chopped closer to the length it will be masticated during the ingestion phase, the cow will take less time eating her diet and then can go to a comfortable free-stall and chew her cud!
Then W.H. Miner Research Steps In
This is where timely research from the W.H. Miner folks comes in. Dr. Rick Grant, et al., in 2018 reported on their findings that cows reduced feed particles to a uniform size. This size is 8 to 11 millimeters. There are 25.4 millimeters in an inch. So, this means all forage particles are reduced to about a third of an inch to just under ½”. Another of the findings of the feeding trials at WH Miner was that it takes extra time for the cow to do the particle reduction. It was also shown that if the field chopping crew reduced particle size further so that little forage stays on the top screen of the PSPS and most settles in box two and three, the cows would eat fewer minutes per day, but still eat the same amount of feed.
Specifically, Grant, et al, found reducing particle length nearer the size which the cow regurgitates her feed in boluses to chew her cud, reduced eating times occurred without reducing effective fiber (peNDF) and rumen health. The trial report is available online by searching Relationships Between Fibre Digestibility and Particle Size for Lactating Dairy Cows. (I am not smart enough to create a hot link!).
There were two types of diets where this information is crucial. First, Grant, et al. discovered when a diet contains too much uNDF 240, dry matter intake (DMI) will be reduced significantly. The amount of uNDF 240 the cows can consume is a fairly hard number. And it is a much more accurate number to determine DMI than previous attempts with ADF, NDF, and lignin. (For more on this see uNDF 240 is the New Lignin in the forageinnovations.guru website under archived newsletter articles.) Miner research found that reducing particle size of high uNDF 240 returned a significant amount of the DMI on these diets. However, having too much uNDF240 is not typically the case for Forage Innovations clients!
So, What is the Deal about Another Budget?
Often the term budget refers to topics other than money although paying attention to a cow’s time budget will also mean dollars! The second type of diet where particle size is crucial is when the cows are eating a high-forage diet. This is where spending less time at the feed bunk processing her feed down to between 8 and 11 mm allows her to spend more time ruminating in her stall. This is a more important place for her to be when eating a high-forage diet. Processing to a finer metric than has been done in the past becomes an aid to the in setting the cow’s daily budget of time. Just like people, we only get twenty-four hours per day.
An added benefit to this FPL reduction is that finer processed TMRs are a tremendous help in preventing the cows from sorting their diet.
And this is why most Forage Innovations clients process their forage samples a little finer and why judging a forage sample under the “old’ forage standards may be inappropriate in these days of high-forage diets and high-producing dairy cows.