There are many choices when it comes to silage hybrids. G. W. Roth, associate professor of agronomy at Penn State, and A. J. Heinrichs, professor of dairy science at Penn State, share four popular silage hybrid types, describing the pros and cons of each.
Conventional hybrids exhibit variation in dry matter and fiber digestibility. Many seed companies have evaluated their existing conventional hybrids for dry matter and fiber digestibility and have developed a list of hybrids recommended for silage production. It is possible to find high-yielding lines with above-average dry matter digestibility and fiber digestibility. The challenge is that little independent testing data is available. Use research-based seed company recommendations to identify the best conventional hybrids, and follow up by monitoring the dry matter digestibility and fiber digestibility of your silage.
Leafy hybrids contain a gene that results in an increase in the leaf content of the silage. In one trial, the leaf content of the silage was 12% for a normal hybrid and 13% to 16% for the leafy hybrids. Leafy hybrids vary in their characteristics somewhat, but they tend to yield close to, or better than, the level of yield for conventional hybrids and have softer kernels that dry down more slowly.
Some leafy hybrids may have less starch and more fiber than conventional hybrids. Digestibility and fiber digestibility ratings of the leafy hybrids have shown mixed results compared to conventional hybrids. There is considerable variation among the leafy genotype, so be sure to check with your seed supplier regarding specific management recommendations. Some leafy hybrids are designed for silage-only use; some have a relatively faster stover drydown rate.
Brown midrib (BMR) hybrids have superior fiber digestibility, and some feeding trials have shown that use of these hybrids can increase milk production by several lb. per cow. However, BMR hybrids also have yielded about 10% to 40% less silage than conventional hybrids in our trials. This lower yield, in conjunction with the high price of the seed, has limited the adoption of these hybrids. If consistent 2 lb. to 3 lb. per cow increases in milk production could be achieved, this would offset costs associated with the lower silage yields of this material. The economic benefits of the BMR hybrids are maximized when this silage is stored separately and the ration is carefully balanced to take advantage of the increased fiber digestibility.
Waxy corn also can be grown for silage. The grain of waxy corn contains 100% amylopectin starch (branched chain glucose molecules) rather than the 75% amylopectin starch in normal dent corn. Feeding trial results have been inconsistent. Some results have suggested slightly greater feed efficiencies with waxy corn and corn silage, while other trial results have not shown any differences between waxy corn and regular dent corn. Waxy hybrids can produce yields similar to, or slightly lower than, conventional dent hybrids.
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