HARLEYSVILLE, Pa. – This year is not the year to be a poor crop manager.
If you’re harvesting wet corn for silage, there’s a chance poor quality feed will come out of the silo unless you work hard now.
Weather-damaged crops could have enhanced plant disease susceptibility, says Pioneer Livestock Account Manager Rich Lutz, and an increased probability of mycotoxins.
Ensiling at higher-than-normal moisture may lead to prolonged fermentation, excessive protein breakdown, and energy loss.
Problems lurk. Incomplete fermentation and increased likelihood of secondary clostridial fermentation often result when crop managers make hasty decisions to harvest and ensile corn before moisture levels drop into recommended levels.
Lutz said this is because fermentation bacteria deplete soluble sugars that are available for the production of silage acids.
Large amounts of silage acids may be produced, however they will be diluted out in the wet forage mass and not be able to achieve a desirable low pH. An environment conducive to Clostridial activity develops if pH doesn’t fall below 4.5.
Prolonged silo filling time of damaged corn contributes to aerobic instability because of the accelerated dry down.
Crop managers sometimes are forced to ensile wet corn silage. One option is to add dry grain by-products such as beet pulp to lower moisture levels or molasses to add substrate to wet forage. Lutz said this will help lessen the probability of secondary clostridial fermentation.
Try separating forages. Large structures that are filled with forages of several qualities may cause good silage to become contaminated with poor silage.
Segregation of stressed forages into separate silos is advisable, such as using bagged silos. Dairy managers who detect health and production problems from feeding the stressed silage then have the option of allocating the feed to other livestock groups or else disposed back into the field.
Old vs. new. Be sure to compare the nutritional value of last year’s corn silage to new crop corn silage.
Lutz warns, however, that routine NIRS analysis does not provide enough information about energy availability regarding how the damaged corn silage will feed, since energy predictions are based upon ADF driven regression equation.
Running comparison corn silage samples through laboratories that offer starch analysis and digestibility testing will predict how the newly ensiled crop will differ from the old crop.
Don’t rush fermentation. Maintaining diets with fermented silages minimizes the chances of ruminal acidosis. Existing forage inventories should be fed at higher inclusion levels until this year’s corn is properly fermented.
Producers facing forage shortages usually feed the new silage crop before fermentation is complete.
Forages require two to three weeks after ensiling to properly ferment, regardless of the storage structure.
The only way to speed up fermentation is to incorporate a well-researched inoculant that contains bacterial strains proven to promote fast fermentation efficiency.
Usually forages treated with quality inoculants are completely fermented in one week.
Post-harvest management. Before deciding to dispose of damaged silage, managers should utilize laboratories that offer fermentation testing services to determine silage quality in more detail, Lutz recommends.
Silages that are ensiled with aerobic instability can be identified by poor bunklife (hot forages), less total energy availability, production of molds, animal intake and production problems, and mycotoxin production.
Silages that undergo clostridial secondary fermentation display green, slimy, unpalatable silage and lose up to 50 percent in dry matter and nutrients.
pH is key. pH is a key criterion to evaluate silage fermentation, Lutz said.
Generally, the lower the pH, the better preserved and more stable is the silage.
However pH alone is not a totally accurate monitor of silage fermentation.
Determination of silage acid levels that contribute to lowering pH is needed for further forage analysis.
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