Corn silage harvest errors

These five corn silage harvest errors occur too often

by Paul Dyk

IT’S corn silage harvest season — a short window of time that affects dairy profitability all year long. What can go wrong? Unfortunately, there are many things that can and do go awry on an annual basis. Some are out of our control while others are not. In my experience, here are five corn silage harvest mistakes that happen too often and have a profound negative impact on the crop we’ll feed over the next year. 1. Poor communication: After the harvest season, it’s easy to assess that something went wrong. The fingers start pointing. The chopper was set according to the manual, but the corn silage was chopped too fine. The reality is that most harvest issues are people issues and not weather or equipment related. The solution, of course, starts with pizza.

Get your forage team together a couple weeks or months before harvest. This group should include the people doing the chopping along with your agronomist, nutritionist, operations manager, and the owner. Decide who will monitor chop length and kernel processing. Make sure everyone shares their phone number and maybe start a WhatsApp group.

Do a little math together while you eat another slice of pizza. Are there enough packing tractors? If there is a new employee on a packing tractor, start by having an experienced employee ride with them. Finally, develop a plan for covering the pile or bunker. Create a harvest culture of less finger pointing and more pizza. 2. Inadequate capacity: This is ranked second because as operations expand, capacity becomes a bottleneck. One chopper used to be okay, but now it’s often taking too long to chop, and dry matter targets are being missed. Bringing in a second chopper sounds good, but you need to ensure a corresponding amount of packing capacity. Following the 800-pound rule is a good starting point. This simply dictates that there be 800 pounds of packing capacity per ton of corn silage delivered to the pile or bunker per hour. It’s also critical that you have experienced pack operators (usually highly undervalued) who can get the job done. 3. Missed dry matter targets: Start monitoring crop dry matter (DM) much earlier than you think is necessary. It gets everyone on the team thinking about a target date and prepping for the labor surge. Depending on the year, soil type, and corn hybrid, the corn silage may hit the desired target earlier than what a guess on a drive by at 60 miles per hour may indicate.

I like 34% DM (66% moisture). When corn was $2.50 per bushel, I used to lean toward chopping earlier to make sure we didn’t miss the window and harvest too dry. But things have changed. As corn matures, the nuggets of gold (grain filled with starch) begin to increase in weight rapidly. Going from 30% starch to 35% starch cannot be overlooked.

Why not just let it go to 40% dry matter? As the plant matures, fiber digestibility goes down. Dairy cows need a minimum amount of fiber, and you want to maximize that fiber digestibility.

For larger dairies with seven to 14 days of chopping, hitting a specific DM percent is not easy. Monitoring DM status across multiple fields can help. Staging hybrids is a good idea, but realize that hot, dry weather can begin to squeeze your harvest window. Thinking back to previous harvests might give you a better handle on what worked, or didn’t work, in the past.

On-farm moisture testing is a standard practice on most dairy farms. Doing one sample is relatively easy, but how do you handle 10 samples? Koster testers, microwaves, air fryers, and dehydrators can all work, but each has its challenges. Perhaps one option I don’t see very often is a forced-air convection oven. It will cost about $3,000, but it’s accurate, safe, and can handle multiple samples. Spread over a lot of tons over a few years, it’s worth consideration.

4. Improper processing and chop

length: I’m as good as anyone using a Penn State Particle Separator, but I don’t like to use it to measure particle length on corn silage. High-starch corn silage will have extra weight on the bottom pan, which impacts the percentages on the other pans.

I prefer using a caliper or ruler to measure the chop length on leaves and stalks, targeting 19 to 24 millimeters depending on the hybrid. Telling the harvester operator to set the chop length to 3/4 of an inch is not a guaranteed recipe for success. Measure the actual corn silage coming out of the chopper to verify the desired chop length is being achieved. Kernel processing has been much improved over the last 20 years. As with cut length, look at the harvested corn silage rather than just setting the chopper to a specific roll gap.

Setting up identical choppers the same way does not necessarily guarantee they will chop the same. Wear and tear on rollers and cutting bars can yield different results. When you change fields and as the season progresses, keep monitoring. Drier corn and different hybrids will process differently.

During harvest, sending a sample to a lab to obtain a kernel processing score isn’t going to work if your chop window is three days. An immediate, accurate analysis is needed. This requires someone with experience who knows corn silage.

5. Either not using or the improper

use of inoculants: The research is clear that inoculants can reduce shrink and improve fermentation; however, research does not ensure that you purchased enough inoculant, the application equipment is working, or someone remembered to turn that equipment on.

Buy a good inoculant from a reputable company. They usually cost about 50 to 60 cents per ton. There are only about four to five companies that actually make inoculants. Buying direct from these companies will help control costs. If you have difficulty keeping up with the pile or bunker face during the year, consider using a Lactobacillus buchneri inoculant, which produces acetic acid and greatly extends aerobic stability. •

PAUL DYK

The author is a dairy nutrition consultant with GPS Dairy Consulting LLC and is based in Malone, Wis.

Forage and feed proteins are complex

DURING nutrition workshops with students and industry professionals, I generally break nutrition analysis training down into sections corresponding to nutrients or nutrient digestion measures. Within the nutrient section, the classifications we discuss include protein, carbohydrates, fat, ash and minerals, and fermentation compounds. Protein and nitrogenous compounds tend to be the first nutrient class we delve into only because these compounds are listed first on most forage and feed analysis reports.

Crude protein is the anchor

Forages tend to be between 5% and 30% crude protein on a dry matter basis. Explained in pounds-per-ton terms, this equates to between 100 and 600 pounds of crude protein per dry ton. With expensive soybean meal and protein prices, this makes protein an incredibly valuable component of forage; however, crude protein is just what the name implies — a crude measure of the actual amino acid and protein content in the forage.

In the feed analysis laboratory, crude protein is determined by measuring the total nitrogen (N) and then multiplying that value by 6.25. Crude protein doesn’t necessarily equate to usable true protein and amino acids in fermented forages, hence a better understanding of nonprotein or bound protein measures in forage crops becomes important.

Nonprotein nitrogen differs

Fresh forages and hay crops tend to have very small amounts of nonprotein-N (NPN), except in cases where nitrate-N is taken up by the plant in considerable quantities, and the living forage is unable to convert this nitrate-N into amino acid and protein fast enough. This situation tends to be associated with extreme drought stress followed by a rain event and harvest, or soon after a killing frost. In both cases, there can be a considerable amount of nitrate-N included in the crude protein fraction; however, this NPN is not true protein and is toxic to ruminants in high amounts, acting like cyanide.

Fermented forages contain a different NPN form from fresh or hay crops. This NPN is measured as ammonia-N and represents broken down protein and amino acid, resulting from fermentation bacteria and microbial protein degradation. Ammonia-N can also result from proteolysis following extensive enzymatic activity.

We can use ammonia-N measures in a couple of practical ways — either to identify an inefficient forage preservation or to assess the extent that corn grain and silage has fermented.

A 10% ammonia-N rule of thumb applies to haylage crops, whereas the goal is to have 10% or less of the total crude protein measured as ammonia-N. Alternatively, this means that 90% of the crude protein has been conserved in protein or amino acid form. When ammonia-N is greater than 10% of the total crude protein, the forage has likely fermented inefficiently and the true protein value of the feed isn’t optimized.

For corn grain and silage, the protein in the feed is of lesser interest relative to the starch and energy component. Silage and high-moisture corn offer exceptional energy per pound due to excellent starch digestibility following ensiling. With these feeds, 10% or greater ammonia-N indicates adequately fermented silage or high-moisture corn, and this implies that the silage or grain is feeding to its full potential.

Measured crude protein isn’t always usable true protein. It’s important to understand nonprotein and bound protein measures.

Mike Rankin

Bound protein of little value

The final protein fraction laboratory measure is undigestible protein, which is found in the acid detergent fiberbound fraction. Some protein is inevitably locked within forage fiber. Of particular interest is the protein that is bound so tightly to fiber that even a strong acid detergent can’t break the protein loose. This is defined as acid detergent insoluble crude protein, or ADICP.

With an efficient fermentation or hay preservation and no heat damage, the ADICP should be less than 1% of the total forage. If this value is greater than 1%, there is reason to believe that substantial heating in the ensiling or curing process took place and bound too much protein into an indigestible form.

Hay that heats because it was harvested at too high of a moisture content will often have a high ADICP value, especially if it “caramelizes.” This undigestible protein passes through the animal without providing any value and should be subtracted from the total crude protein when balancing diets.

Looking toward the future of animal nutrition, we’ll likely progress toward amino acid measurements as a more accurate depiction of the true protein content in feeds. However, for the immediate future, the crude protein, nonprotein nitrogen, and bound protein measures remain the bedrock for dairy or beef nutritionists to formulate diets.

Next time you review your forage analyses, identify and interpret the protein measures discussed here. In following “Feed Analysis” columns, we’ll cover the other sections with a goal to advance your feed analysis report interpretive skills. •

JOHN GOESER

The author is the director of nutrition research and innovation with Rock River Lab Inc, and adjunct assistant professor, University of WisconsinMadison’s Dairy Science Department.

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Harvest Year Category Crop/plant/sample specifications

August 25 2022 Dairy Hay >75% legume; grown by active dairy producers

August 25 2022 Commercial Hay >75% legume; commercially grown and sold in large lots off the farm All hay samples: Must be from a bale, any type or size; use of a preservative or desiccant is allowed.

August 25 2022 Grass Hay >75% grass

August 25 2022 Baleage Any mixture of grass/legumes Baleage: Must be processed and wrapped as baleage and show signs of fermentation.

August 25 2022 Alfalfa Haylage ≥75% legume

August 25 2022 Mix/Grass Hlg <75% legume All silage samples: Must be ensiled in a normal preservation process and show signs of fermentation. Use of a preservative is allowed. Additives affecting fiber content or any other adulteration will disqualify the sample.

Samples analyzed for

(expressed on a dry matter basis):

Hay, Baleage, Haylage: Dry matter, crude protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), neutral detergent fiber digestibility (NDFD), relative forage quality (RFQ) and milk per ton.

[RFQ is a ranking of forage quality based on NDFD and should not be confused with or compared to Relative Feed Value (RFV).]