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How to pick a hybrid for silage

Art Graves Published on 30 October 2009

Production of high-quality corn silage depends on many factors – ranging from optimum growing conditions to ideal moisture levels at harvest to proper packing in the storage structure. However, one factor that dairy producers often overlook is selecting the appropriate hybrid for corn silage production.

The goal for most top dairy producers is to produce the most milk at the most economical cost possible. This is especially true given today’s economic challenges.

Making an informed corn hybrid choice will not only help maximize the feeding value of your silage but will help you take full advantage of your herd’s milk production potential. For years, many producers believed the best grain corn hybrids also produced the best corn silage.

However, with changes in technology and the availability of various analytical tools, we now know this is not the case. That’s why it is so important to select a corn hybrid that is specifically bred for silage production – providing high neutral detergent fiber digestibility (NDFD), as well as yield, for maximum feed value and milk per acre.

Selecting a hybrid with a high NDFD can improve dry matter intake, allowing for more forage and less supplemental grain in the ration, which can in turn lower feed costs.

The accompanying table illustrates the main differences between specialized silage hybrids and conventional or dual-purpose hybrids, which are bred primarily for high grain yield (see Table 1*).

Grain yield
Unlike grain corn hybrids, maximizing bushels per acre shouldn’t be the primary consideration when selecting hybrids for corn silage production. However, adequate grain yield is still needed to ensure the silage delivers high energy and nutrient value to the cow.

Forage yield
While forage yield is not important when selecting a hybrid for grain corn production, it is a key factor when selecting a hybrid for corn silage. High tonnage yield provides increased dry matter and nutrients for the herd.

Stalks
A corn hybrid bred for grain usually features a stalk that stays green with high lignin content to strengthen the stalk and help it stand through the fall. But standability is not a crucial factor for hybrids bred for corn silage because the plant does not have to stand in the field through grain harvest. In fact, it’s important to select a hybrid with lower lignin content in the stalk, since lignin is less digestible by the cow.

Brown mid-rib (BMR) corn silage hybrids are examples of hybrids with low lignin content, making the silage more digestible and resulting in increased dry matter intake and improved milk production.

Leaves
Long, wide leaves capture sunlight that benefits all corn crops, but extra leaf area is even more important for silage corn because of the additional tonnage it provides. Leafy hybrids are popular varieties with a greater number of leaves above the ear – as many as eight or nine compared with only five or fewer for a nonleafy variety.

Also, some leafy hybrids have a slightly longer harvest window, which can be an advantage in some situations. Although leafy hybrids may add to high forage yield, they may not add significantly to NDFD.

Kernel characteristics
Hybrids bred for grain corn production should have hard kernels and be fast-drying to withstand harvesting and shipping. But hard, dry kernels resist digestion, making them a poor fit for silage. So when selecting hybrids for silage, a softer, high-moisture kernel is preferred. This results in better starch digestibility, increasing energy content and milk production.

Plant drydown
Grain corn hybrids are bred for very fast ear drydown while the stalk stays wet for staygreen. When selecting a hybrid for silage, look for uniform plant drydown from the ear to the stalk. This will ensure consistent moisture levels at harvest.

Relative maturity
One method that is commonly used to select the appropriate maturity for silage hybrids is to first determine the full-season relative maturity for grain hybrids planted in a given geography. Then add five to 10 days to the maturity and choose a silage hybrid that is rated for that relative maturity.

As an example, in a zone with a 95-day relative maturity for corn grain, an appropriate range of maturity for a silage hybrid would be in the range of 100 to 105 days.

Tools for selecting a silage corn hybrid
When selecting a specific hybrid for silage production, the best places to start are seed company catalogs or websites. Look for hybrids that are specified as silage products, and don’t be afraid to ask your seed supplier for trial data or quality tests to back up claims that a hybrid is suited to silage production.

Regardless of the hybrid selection you make, it is important to do your research and consult independent performance data before making a purchase. There are several ways producers can access this type of information. In addition to reviewing independent and university research, there also are several online tools available.

CornPicker for silage is available through Michigan State University and can help producers select hybrids that will work best on their farms. It is a spreadsheet that can help you compare hybrids by calculating partial budgets based on information you input. You can find a sample of the CornPicker spreadsheet at www.msu.edu/~mdr/cornpicker1.05.xls

Another tool is the Milk2006 equation available through the University of Wisconsin – Madison. Milk2006 can help you evaluate hybrids for quality and milk production. You can find a sample of Milk2006 at www.uwex.edu/ces/dairynutrition/documents/milk2006cornsilagev.xls

Another thought to consider is to simply ask other producers in your area what they’ve had success with.

Impact of hybrid selection
To illustrate some differences in selection criteria, let’s look at an example from a previous year’s harvest to show how a producer could have benefited by selecting a hybrid that was specifically bred for silage production versus one that was bred for grain. If we look at the economics of the 2008 growing season in the northeastern U.S., we had a tremendous crop of corn silage.

However, producers were paying up to $7 a bushel for grain. A grower producing a lot of corn silage – from a hybrid not selected for silage – would have wanted to make the most out of it and purchase less high-value grain. But even if yields were excellent, if that silage was not highly digestible, the producer would still require a large amount of $7-per-bushel grain to meet the herd’s energy needs.

Highly digestible, high-yielding corn silage could have saved on purchased grain expense, resulting in a much more economical diet. Hybrid selection is one of the most important management decisions a producer makes – even more so this year given the current economic situation.  PD

*References and tables omitted but are available upon request at

Art Graves
Agronomist
Mycogen Seeds

See more articles like this at www.progressivedairy.com

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