Nitrates in Drought Damaged Corn

High temperatures and extremely dry soils have certainly taken a toll on corn fields in Delaware.  Thundershowers continue to be sporadic throughout the area and the forecast is not indicating any drought-ending rainfall.  One way to manage the damaged corn is to harvest for silage.  Before chopping, it’s a good practice to sample a few plants throughout the field for nitrates.  Typically, the highest concentration of nitrates are found in the lower third of the stalk.  Therefore, cutting a little higher than normal could be beneficial.  Corn put in the silo will lose a percentage (30-70%) of nitrates during fermentation.  This may take several weeks to complete and feeding the drought damaged corn should be delayed.  Several private forage testing laboratories in the area can test for nitrates.  The Delaware Department of Agriculture in Dover can perform the test for nitrates. It is free for Delaware farmers. 

Suggested Reading:

Read More

Spring Silage Time

Many dairy farmers in the area are chopping forage for spring silage.  Popular choices for spring silage include alfalfa, rye, barley, and triticale as well as wheat with hairy vetch or barley with red clover.  Small grain silage allows farmers to increase forage supplies while still allowing silage corn to be grown as a full season crop.  Corn silage will then be chopped in early fall which serves as the main feed ingredient in a TMR.  Typically small grains such as rye used for silage will be mowed at the boot stage with a discbine , allowed to wilt to 60-70% moisture, chopped, and ensiled in a bunker or upright silo.  Below is a picture of a rye field being chopped with a self-propelled chopper west of Harrington, Delaware

Picture 1-Rye being chopped by a self-propelled chopper west of Harrington, Delaware.

Picture 2- Rye that is chopped is being blown into a dump truck which is hauled back to the farm for storage. 

Photographs by Phillip Sylvester, Extension Agricultural Agent for Kent County, Delaware.

Read More

Silage Harvest Season

Silage harvest season has arrived. The following is information on good harvest practices for high quality silage.

Harvesting at the correct moisture promotes favorable fermentation in the silage crop and decreases storage losses. Thus, the moisture content of the chopped plant should be the determining factor for when to harvest. For bunkers, silage should contain between 30 to 35% dry matter (65 to 70% moisture). Upright silos and bags can be a little drier at 35 to 40% dry matter (60 to 65% moisture). Silage that is put up too wet results in a butyric acid type fermentation which decreases feed intake and can result in ketosis in early lactation cows. Silage that is too dry will have more and larger air pockets which results in a poorer fermentation and less beneficial acids for cows to use to make milk and meat.

The moisture content of fresh corn plants can be determined by chopping a small amount and using a microwave or Koster tester to determine moisture content. A small digital scale that measures to the tenth of a gram helps obtain more accurate results. Agronomists generally estimate that the corn plant dries down 0.5 to 1.0% per day. To estimate the percent dry matter, you can use the grab test. Squeeze a handful of chopped material as tightly as possible for 90 seconds. Release your grip and if the ball of material expands slowly and no dampness appears on your hand, the material contains 30 to 40% dry matter. However, this method only allows a general estimation of the moisture content of the chopped silage.

During “normal” growing conditions, corn is harvested approximately 40 to 45 days after tasseling. In the past, the appearance of brown leaves was used as a factor in determining the optimum harvest window. With today’s corn genetics, corn plants stay green longer and this target is not an appropriate benchmark.

Moisture content is related to the stage of maturity of the corn grain. Corn is harvested for silage at a ½ to ¾ milk line. However, weather and growing conditions can change the optimum stage of maturity for harvest. An experiment showed that the stage of maturity of the corn plant only correctly predicted harvest moisture content 68 to 85% of the time. Thus, the strong recommendation is to actually measure the moisture or dry matter content of representative chopped corn plants.

Silage needs to be chopped fine enough for good packing to quickly eliminate oxygen and to establish a good fermentation process. At the same time, the chop length needs to be long enough to promote cud chewing. Thus, the recommended theoretic length of chop (TLC) is a compromise between these two factors. Alfalfa haylage or silage should be chopped at 3/16 inch, unprocessed corn silage at 3/8 to 1/2 inch, and processed (kernel processor) corn silage at 3/4 inch.

Adjust silage choppers with on-line kernel processors. The optimum moisture content of silage harvested with a chopper containing a kernel processor is 62 to 65% (35 to 38% dry matter) to capture additional starch accumulation in the corn kernels. Most nutritionists want to see the most of the corn kernels pulverized to a similar size. To optimize starch digestion and provide adequate effective fiber, the recommendation is to cut to ¾ inch theoretical length with an initial roller clearance of 0.12 inches. If kernel breakage is not adequate, the roller clearance should be decreased. To test whether adequate kernel damage is occurring, collect a silage sample from several loads in a 32 ounce cup. Pick out and count the number of whole and half kernels. If the number of whole or half kernels exceeds 2 or 3, improve kernel damage by adjusting the roller clearance (Mahanna, Feedstuffs, 2008). Essentially, the goal is to have between 55 to 64 percent of the kernels damaged.

Keep knives sharp and properly adjusted throughout the filling process. Sharp knives prevent the shredding of silage, resulting in a more uniform chop. This allows for maximum forage compaction, good fermentation, and sufficient particle size to prevent health problems in the cow.

Information extracted from “Tips for Harvesting and Storing High Quality Corn Silage” by Donna M. Amaral-Phillips in the August 2009 edition of Kentucky Dairy Notes

Read More

Dry Corn and Silage

Corn is drying down so fast that in many fields it is drier than recommended to make good silage. The following is information on how to deal with dry silage.

In cases of overly mature corn silage that has high DM content greater than 40%, poor packing and aerobic stability problems at feed out may be the issues to deal with. Very, very dry corn silage (>45%DM) will have reduced fermentation because of lack of moisture for bacterial growth. For dry silages, my suggestion is to decrease chop length (a bit) (for processed corn silage back down from 3/4 to 1/2 inch chop – instead of 15-20% on the top screen of the PSU box go for about 10%) and use an inoculant designed to improve aerobic stability, e.g. one containing L. buchneri. An alternative is to use a buffered propionic acid based product. Fast packing, tight packing, and sealing immediately will be “must do’s” for this drier material.

When forage is too dry, will the addition of water help?

When forage is dry, the addition of water may help in fermentation but the amount of water that must be added to make a difference is substantial. For example, in order to decrease the DM% of a tonne of forage that is 50% to 44%, one must add about 300 lb of water. To further reduce the DM to about 40% requires about 495 lb of water. Another problem with addition of water is that this water may not completely absorb into the forage mass and may actually increase the amount of runoff. Water should be used only in the worst conditions. Instead, use a liquid based microbial inoculant to stimulate the fermentation.

Information from Dr. Limin Kung, Jr, Dept. of Animal & Food Sciences, University of Delaware.

Read More

Corn Silage Considerations

Corn silage season is fast approaching and the following are important considerations in harvesting corn silage for livestock and dairy animals.

Corn Silage Harvest Moisture Timing

Depending on storage structure type corn silage is harvested when whole plant moisture reaches 32 to 45% dry matter. Optimum dry matter content for bunker silos is 32 to 35%; ag bags — 32 to 37%, conventional upright silos — 32 to 37% and oxygen-limiting silos — 40 to 45% dry matter.

As a corn ear matures the sugar in the kernels begin to change to starch. When this occurs, the kernel shrinks at its top and the “dent” forms. At denting if you break an ear in half you will see the milk line of the kernel on the bottom side of the tip half. When the milk line is ¼ of the way down the whole plant, dry matter is approximately 30%. When the milk line is approximately ½ down the kernel, dry matters are approximately 35%.

Proper moisture at harvest is critical and there is a wide variation in the actual moisture of the crop based simply on the milk layer. The most accurate measurement of whole plant dry matter is to conduct moisture testing. Begin by taking a few plants from selected fields at dent stage. Run through some type of chopper or lawn mower and thoroughly mix together. Use a Koster tester or a microwave to determine whole plant dry matter.

This moisture can then be used to predict harvest date. The expected dry down rate for corn silage is 0.5 to 0.6% per day. For example, if your crop tests at 70% moisture and your target harvest moisture is 65% you need an additional dry down of 5%. Dividing by the dry down rate of 0.5 to 0.6% per day indicates that you can expect to be harvesting in 8 to 10 days. Be sure to test the actual moisture content again at and during harvest.

Length of Cut

Recommendations for length of cut for silage vary depending on crop condition. Drier crops should be cut finer to produce smaller particles that minimize air pockets. Use of highly digestible hybrids requires a slightly longer cut to maintain effective fiber. General recommendation is a 3/8 inch theoretical length of cut (TLC) but more mature crops may require a shorter length. For non-processed silage the recommended chop length is 3/8 to ¾ inch TLC. Some farms rely on their nutritionists to fine tune the chop length based on farm specific conditions.

Height of Cut

In recent seasons some producers are cutting silage at a 10 to 20 inch height. This practice reduces silage fiber and lignin percentage and increases starch and energy content. However silage yields are reduced five to ten percent. Higher chopping can also be used to change whole plant moisture contents. By cutting higher, harvest may advance by 3 to 4 days. Higher chopping may be an option if excess forage dry matter is available. However, this will increase the final cost per ton. To balance this trade-off between quality and yield, the decision should be based on an economic assessment.

Processing Silage

At lower whole plant moistures, crop maturity may affect silage quality. Fiber and starch digestion decreases as corn dries down. Processing at harvest may be needed to maximize digestion on more mature crops. The goal of processing is to ensure breakage of the kernel and cob to assist digestion. Processing also can affect fiber length so choppers equipped with a processor typically lengthen their cut to ¾ inch.

Silage harvest will be just around the corner, will you be ready??

Reprinted from “Corn Silage Harvest” by Paul H. Craig in the August 5, 2008 edition of the Penn State Field Crop News.

Read More

Placing a Dollar Value on Silage

I was recently asked what the value a cattle feeder should put on home grown corn silage for budgets in 2008. Silage price should increase along with the value of corn for grain. However, silage has a lot of moisture and costs associated with transport and storage and there is not a straight line relationship. The following is an article with thoughts on how to value different types of silage and haylage.

Unlike with grains and even hays that usually have a base market price or value, silage crops are not routinely traded and thus arriving at a fair value for both the buyer and seller can be a problem. Corn, alfalfa and wheat silage are the most common.

Following is a brief discussion of some methods for determining prices that can be used. Since silages may contain 50 to 70% moisture, their amount of actual feed or dry matter varies greatly and should be taken into account. Thus, the first question one would ask or determine when dealing with silages is, what is the moisture or dry matter content? If dry matter content is not known, then it should be determined.


There are a number of methods and formulas used to determine the value of whole plant corn silage. They vary greatly in their degree of complexity but surprisingly all result in similar values. A “quick and dirty” method, is to use a factor of 8 to 10 times the price of a bushel of corn grain to obtain the price per ton of silage. A factor of 8 to 9 best fits for an “in the field” price, whereas a factor of 9 to 10 fits best for silage in storage. Use the higher range of the factors when corn grain is priced at $2.50/bu or less and use the lower range when grain is priced $3.00/bu. or more. Given a corn price of $5.00/bu., these factors would result in silage being priced at $40.00 to $45.00 per ton.

I prefer to use a method that is more complicated but takes into account moisture content of the silage in addition to the price of corn grain.

First, the method assumes that the dry matter of whole plant corn silage contains 50% grain. This can be adjusted if necessary.

Let’s go through an example to see how the method applies. We’ll assume that moisture content of the silage has been checked and found to be 65%. Therefore, dry matter content is 35%. To determine the amount of dry matter per ton, we simply determine 35% of 2000 lbs.
2000 lbs. x .35 = 700 lbs. dry matter per ton of whole plant silage
700 lbs. dry matter x .50 = 350 lbs. of grain dry matter per ton
350 lbs. grain dry matter x .85 = 411.8 lbs. no. 2 corn 56 lbs./bu. = 7.35 bu. no. 2 corn
If we again assume $5.00/bu., value of grain in the ton of silage is: 7.35 bu. x $5.00/bu. = $36.75.

Additional charges or costs should be made to cover the additional costs such as fertilizer, harvesting and storing of silage compared to corn grain. I use a value of $1.00 per 100 lb. of silage dry matter per ton to cover these costs. Here again, this value could be adjusted if conditions warrant.

For our example, there are 700 lbs. of dry matter per ton. Thus, $1.00/cwt. results in an additional value of $7.00. Adding the cost of the corn grain $36.75 and the $7.00 results in a total cost of $43.75 per ton of whole plant corn silage. This value is near that obtained earlier using a factor of 9 times the price of a bushel of corn. You might ask why go through all the extra calculations?

Let’s quickly take another example, but in this case the silage contains 60% moisture rather than 65%. Therefore, there are 800 lbs. of dry matter per ton as compared to 700 lbs.
2000 lbs. whole plant silage x .40 = 800 lbs. dry matter per ton
800 lbs. dry matter x .50 = 400 lbs. of grain dry matter per ton
400 lbs. grain dry matter x .85 = 470.6 lbs. no. 2 corn 56 lbs./bu. = 8.40 bu. no. 2 corn
8.40 bu. x $5.00/bu. = $42.00 for the grain
Adding $8.00 for the 800 lbs. of dry matter, results in a total value per ton of $42.00 plus $8.00 = $50.00. This is a difference of $6.25 per ton or represents $625 for every 100 ton of silage purchased or sold. Also, this difference occurred with only a 5 percentage unit change in silage moisture/dry matter content. Thus, it is important to take into account the moisture content of corn silage when determining its value. In addition, other factors such as spoilage and quality must also be given consideration.


For pricing, these types of silages, I usually attempt to arrive at a fair price based upon what the forage might sell for as hay and then adjust according to dry matter content. Hay prices can usually be obtained in the local area.

Let’s assume for example, that hay is valued at $120.00 per ton. What value is fair for similar quality material as silage or haylage? Hay will generally contain around 13% moisture. Thus, a ton of hay contains: 2000 x .87 = 1740 lbs. of dry matter. At 120.00 per ton, each 100 lb. of dry matter is worth, $120.00/17.40 = $6.90.

Assuming that each 100 lb. of dry matter from silage or haylage has the same value, we simply need to again determine the amount of dry matter per ton. At 60% moisture, there would be 800 lb. of dry matter (2000 x .40 = 800) per ton. Thus, the value of a ton of this particular silage would be 8 x $6.90 = $55.20.

The above method assumes similar costs of harvesting, storing and feeding of hay and silage which may or may not be correct depending upon the situation.


I know of no easy straight forward method for pricing these silages. A suggestion is to compare them with either hay-crop silages or corn silage depending upon the stage of maturity when the small grain silage was harvested. If harvested in the boot stage, feed value in terms of crude protein and energy will be similar to that of high quality hay-crop silage. Thus, a value can be based upon hay as discussed earlier. If, however, the small grain is in the dough stage when harvested, crude protein will be similar to that of whole plant corn silage, but energy value 80-85% that of corn silage. Thus, in this situation, the value of corn silage can serve as the base with an adjustment made for the lower energy value. Again, taking moisture into account will be important and can greatly influence value per ton.

Modified from Determining a Value For Silage Crops by Kern S. Hendrix, Professor Emeritus, Department of Animal Sciences, Purdue University

Read More

What Smells From Silage Can Tell You

Livestock and Dairy producers in Kent county have been making silage for the past month. One indicator of silage quality is the smell. The following is an article on this subject.

Can you tell the quality of silage by smell? The answer to that question is sometimes yes, but sometimes no. When producers detect ”sweet” smelling silage, they often think that this is good. However, this is not necessarily so, since the “sweet” smell is probably coming from high concentrations ethanol (produced by spoilage yeasts) mixed with acetic acid. A high concentration of ethanol that is usually easily detected in high moisture corn and in corn silage, is an indicator that a significant amount of dry matter may have been lost. This silage will also most likely heat very rapidly in the bunk. In fact, the best type of silage fermentation, that is called homolactic acid fermentation, should have little or no distinct smell because lactic acid has almost no smell.

Butyric acid in silage smells rank, rancid, and sometimes fishy (due to protein degradation). The butyric acid smell is commonly associated with silages that are too wet. You probably will never smell this odor if silage that has a dry matter content greater than 35 to 40%. Ironically, silage with a high butyric acid content is very stable when exposed to air and will not heat, but this silage is low in energy content.

If your silage smells like “vinegar”, this is a sign that heterolactic fermentation (a less desirable type of fermentation) occurred because vinegar is acetic acid. Silage with high concentrations of acetic acid is usually stable when exposed to air but sometimes-high concentrations of acetic acid can depress dry matter intake in cattle.

Another common smell in silages is often associated with dry alfalfa silages (usually greater than 45-50% DM) and can be described as a “tobacco/molasses” type of smell. This smell comes from the fact that excess heat has caused proteins to bind with fiber and sugar molecules via the “non-enzymatic browning reaction”. A mildly, sweet tobacco/molasses type smell is okay in alfalfa silage but any hint of this smell in corn silage is a definite indicator of heat-damaged protein. Normally, heat damaged protein in corn silage is only a problem if the DM is in excess of 45% DM. In all silages, when the smell turns from tobacco-like to burnt, you can be sure that excessive heating has taken place. Silages suspected of having excess heat damaged protein should be tested for bound nitrogen (also known as unavailable nitrogen or acid-detergent insoluble fiber, {ADIN}) and protein requirements adjusted accordingly.

The last smell that is commonly associated with silages is the “musty- moldy” smell that comes when silage has undergone aerobic spoilage. The smell of moldy silage is very distinct. However, this is not always an indication of mycotoxin formation. Silages that smell moldy are usually hot and steamy (or have already gone through a heat). In addition to extensive losses in nutrients and dry matter, such silages are very unpalatable.

Article by Dr. Limin Kung, Jr., Department of Animal and Food Sciences, University of Delaware

Read More

Droughted Soybeans as Hay or Haylage

I have recently been asked about harvesting drought-damaged soybeans for hay or haylage/silage. Soybeans are a good alternative or emergency source of livestock feed if managed correctly. Ideally, soybean hay should be harvested when 50 percent of the pods have immature beans. If beans have few pods they can also be used to make hay. In practice, soybeans can be cut for forage at any stage from the time the plants have achieved some height until the beans are almost fully developed. Quality of soybean hay is variable but typically contains 16 to 19 percent crude protein, and 50 to 55 percent TDN if harvested when 50 percent of the pods have immature beans. Once leafdrop starts, forage quality drops rapidly and soybeans probably should not be harvested for forage after this point. A common problem with soybean hay is that the immature beans dry slowly in the pods and often mold inside the hay. Crimping the hay with a mower conditioner will make the drying more even, but the pods are still the slowest drying part of the plant. Waiting to bale until the pods dry fully will also reduce this problem, though more leaves will be lost. Chopping soybeans for silage will minimize this problem. Another problem with soybean hay is that it does not weather well when stored outside. Large round bales of soybean hay when left unprotected from the rain will deteriorate much more rapidly than grass hay. It is common to lose 50 percent of the forage to weathering if the hay is left unprotected. Storing soybean hay in a well-drained and covered stack or in a barn is imperative. Often, soybean hay is stemmy and may be refused by livestock. Typically, 10-20 percent of soybean hay is wasted during feeding due to the coarse stems. If soybeans are harvested for silage, or if soybean hay is chopped in a tub grinder, cattle will eat almost all of it. However, the stem contains high levels of fiber and low amounts of digestible nutrients.

Soybeans can make good silage if two conditions are met. 1) If seeds are well-developed do not chop for silage (too much oil) 2) If seeds did not develop or are small, silage is an option if dry matter content is ok. Prior to chopping beans for silage, check dry matter content. If the plant contains less than 45% dry matter (at least 55% moisture), the plants should ferment fine in upright and bag silos and will usually ferment ok in bunker silos and wrapped big bales. If the plant contains more than 50% dry matter (less than 50% moisture, fermentation quality will probably be poor in bunker silos and balage. When dry matter is much higher than 55% fermentation will be poor in all types of silos except sealed structures. If plants do not contain enough moisture for fermentation, water can be added but it takes a lot of water to change the dry matter content. To increase the moisture content of 1 ton of material by 4 percentage units (for example 55 to 51% dry matter), you have to add about 190 lbs. of water (24 gallons per ton).

A word of caution: soybeans treated with many herbicides cannot beused for livestock feed. If in doubt, read the label.

Exerpted from drought related articles: Whole Soybean Plants For Cattle by Bill Wiess, Ohio State University and Soybeans for Hay or Silage By Rob Kallenbach, Craig Roberts, and Bill Wiebold, University of Missouri, Columbia

Read More

Prussic Acid (cyanide) Poisoning of Livestock in Drought

Sudangrass, sorghum, and sorghum-sudangrass hybrids are among a group of plants that produce prussic acid (cyanide), which can poison livestock under certain conditions. Also included in this group of plants are johnsongrass, chokecherry, and black cherry.

Certain conditions involving climate, fertility, stage of growth, and anything that retards plant growth and development may increase cyanogenetic glycosides in the plants (the production of cyanide).

In periods of drought, when sudangrass is less than 18 inches tall or sorghum-sudangrass hybrids are less than 24 inches tall, a high prussic acid content may persist because the grass is unable to grow out of the high prussic acid stage. Drought keeps the plants small at the stage with higher prussic acid concentration. Also, drought can reduce the availability of phosphorus to plants, resulting in a high nitrogen-low phosphorus situation that favors higher prussic acid contents.

Risks are greatest with grazing. Greenchop can also contain elevated levels, but since livestock do not graze preferentially, it should be lower in prussic acid (cyanide). Haylage from these crops, once fermented, will not be dangerous as the cyanide is converted and released as silo gas. Dry hay is also not dangerous generally because prussic acid (cyanide) levels will be reduced by 75% or more.

If you are considering pasturing or greenchopping sudangrass or sorghum sudangrass crosses, have your forage tested for prussic acid before you feed or graze. The Delaware Department of Agriculture can perform these tests for you (free of charge, contact their laboratory). Grain sorghums should not be grazed or greenchopped but can be used to make silage.

For more information, read this factsheet from the University of Maryland:
Title: Causes and Prevention: Prussic Acid Poisoning of Livestock. By Kim E. Cassel

Parts of this article were exerpted from this factsheet.

Read More

Pricing Droughted Corn For Silage

With much corn in the county being severly hurt by the drought there may be opportunities to sell the droughted corn to be taken off for silage for use by dairy and beef farms. A question often asked is how should I price this corn to be taken off as silage.

There are several good fact sheets on this subject that can be accessed at these web sites:

Determining the Value of Drought-Stressed Corn from the University of Maryland

Pricing Standing Corn for Silage from Ohio State

Pricing Drought Stressed Corn Silage from the University of Wisconsin

Read More