Late last August, the corn was highly variable as it stood in the field. The corn on hilltops didn’t look very good at all — due to severe drought — but at least it was “combine-able,” says Barry Serier, co-owner of the 1,700-cow Jon-De Farm in Baldwin, Wis.  

Serier knew that it would be a challenge to get good corn silage out of this crop. Moisture content among the plants would be variable, and grain-fill would be lower than normal. But, Serier only had a general idea of what was going on. It would take a series of lab analyses — involving freshly harvested crop samples and, later, samples coming out of the bunker silo — to get a true picture. 

The farm’s nutritionist, Jim Linn, used the lab analyses to adjust the ration. Cows only dropped about 5 pounds of milk per day, on average, last fall when making the transition to the new-crop corn silage. It was about as good as anybody could have hoped for under the circumstances.

“You have to adjust the ration based on what the forages are,” says Linn. “Forages are the foundation of any dairy ration.”

Don’t build your rations on a shaky foundation. Obtain as much information as you can through lab analysis, and then “benchmark” the quality of your forage against previous crops and previous years’ experience to arrive at the best rations for your cows. It will pay dividends. 

Be proactive  

Some regard it as a nuisance to gather forage samples and send them off to a lab. The cost, while nominal in most cases, is another consideration.

Many of you have been putting up silage for years, and have a pretty good idea of what will come out of the bunker or silo without having it confirmed by lab analysis. Most of the time, weather conditions aren’t as extreme as last summer’s drought in the Upper Midwest.

Producers make informed decisions throughout the growing season. But, perhaps the thought process can be systematized even more. Perhaps the “art” of producing good forage and blending it into a ration can be made into a “science.”

That’s where forage benchmarking comes in. Instead of reacting to a bad feed situation once you are in the middle of it, benchmarking allows you to anticipate the situation ahead of time and make adjustments — just as Linn and Serier did at Jon-De farm in Wisconsin.

It allows you to be proactive, points out Bill Mahanna, general manager of forage products and nutritional sciences at Pioneer Hi-Bred International. It allows you to ask yourself, “What is the relative change we are going to be making in energy density or kernel damage or starch content as we move from one pile of feed to another?” he adds.

It’s good to get benchmark results as the crop comes out of the field and also as it comes out of the bunker or silo. The fresh-crop samples will tell you whether you did a good job of timing the harvest; that is, cutting the alfalfa or chopping the corn silage at peak levels of digestibility. The silo samples will tell you if you got good fermentation during the ensiling process.

Indeed, forage benchmarking can help you identify management issues that may be in need of fine-tuning, according to Pat Hoffman, outreach program manager at the University of Wisconsin’s Marshfield Agricultural Research Station. 

Improve milk production

The inherent assumption, of course, is that the more producers and their nutritionists know about their forages, the better job they can do in formulating rations. And that, in turn, will boost milk production and add to the economic bottom-line.

For instance, we are learning more and more about the key role of forage fiber digestibility.

A few years ago, researchers at Michigan State University did a review of studies involving forage fiber digestibility and came up with this rule-of-thumb: For every percentage-point increase in neutral detergent fiber (NDF) digestibility, daily milk production goes up 0.55 pounds. Therefore, if NDF digestibility in the ration goes up eight percentage points, it could mean a 4.4-pound difference in milk per cow per day.

The Michigan State study, reported in the March 1999 Journal of Dairy Science, helped shed some light on the whole issue of NDF digestibility. Indeed, “the digestibility of NDF is a significant quality parameter that has been ignored in past forage-evaluation schemes,” says Randy Shaver, extension dairy nutritionist at the University of Wisconsin. 

NDF digestibility is one of the key pieces of information now reported by testing labs in their forage analyses. By knowing the NDF digestibility, producers and their nutritionists can make the appropriate ration adjustments. For instance, if NDF digestibility is low, they might consider adding high-fiber byproducts to the ration to increase overall digestibility.

Forage benchmarking “is not perfect, but it is remarkably informative at times,” says Hoffman, of the Marshfield, Wis., research station. Recently, a farm in Wisconsin sent some TMR samples to the Marshfield lab and discovered that the crude protein was 15.85 percent, or a couple of percentage points below what it should have been. After catching the problem and increasing the protein, the farm got a 4-pound-per-cow-day milk response.

Yes, forage benchmarking does pay.