Many regions of the country had a challenging silage growing season that included record amounts of rainfall. Getting the crop planted, growing it to maturity and getting the crop harvested in a timely manner have all been challenging for many farmers. Whenever less-than-ideal conditions occur for crop quality or for timing to move the silage crop into storage, it creates the potential to significantly impact fermentation.
“Forage fermentation preserves material, but it is also a process that consumes digestible organic matter. If the forage fermentation has not proceeded correctly, valuable dry matter is lost, and the end product of fermentation is less than desirable for promoting dry matter intake and cow health,” said Ralph Ward, CEO at Cumberland Valley Analytical Services.
When it comes to fermentation, harvesting at the right moisture level is critical. Moisture levels that are too high, which may be the issue with much of this year's crop, can cause prolonged fermentation where the pH does not drop quickly, resulting in excessive protein breakdown. Clostridial fermentation with the production of butyric acid and histamines can occur, impacting dry matter intake and affecting animal health and performance.
Another challenge with adverse weather is that it can deter photosynthesis prior to crop harvest. This results in less sugar content in the crop as it’s harvested or cut and wilted. Sugar content is very important because it drives the fermentation process.
“An evaluation of forages coming out of storage is almost like getting a report card on all of those circumstances that came into the process of making the silage – everything from growing conditions to rainfall to harvest management,” he noted. “Some things are under management’s control and certainly some are not. But by looking at the fermentation analysis, we’re looking for high levels of lactic acid, moderate levels of acetic acid and little to no butyric acid, and we hope to conserve higher levels of dry matter and protein.”
To critically evaluate fermentation and relate it back to management practices for decisions in the future, Ward recommends investing in a chemistry analysis for fermentation data.
“Often, laboratories report fermentation data by NIR. However, NIR evaluation of fermentation constituents is not as accurate as for other constituents like protein, ADF and NDF starch,” he explained.
Ready to Open the Silo?
It’s important to recognize that each area within a region is its own microclimate. While some areas are very challenged, others may not be. Also, varying soil conditions and harvest windows can be vastly different.
“Where forages have been put up wetter, there’s a good potential to see lower sugar levels going in and higher maturity, so do not expect as good of a fermentation,” said Ward. “With corn silage, the primary driver is moisture, and if corn silage went in at 30% to 35% dry matter, there will be a good and significant fermentation, and we’ll get relatively quick rumen starch accessibility as we feed that material out.”
A key part of managing stored crops is to allow time for material to fully stabilize for feeding. Haylage should ferment for at least four to six weeks, he noted. In corn silage, wait at least eight to 10 weeks, but 14 to 16 weeks is ideal and will offer better starch accessibility, which is significant in feed utilization.
Monitor Feedout and Cows Closely
Given the unusual season, now is a good time to evaluate silage inventory closely and ensure you either have enough or determine what supplies are available locally to purchase.
“As you are changing over to begin feedout of your new silage, be sure to start gradually with a step-up program,” said Dr. Renato Schmidt, Lallemand Animal Nutrition Forage Products Specialist. “I recommend adding about 20% to 25% to the ration and then slowly increase. Be sure to monitor cow intake very closely.”
Corn silage will likely be lower energy due to fewer kernels developing on the plant. Also, fungal infestations may have developed while plants were standing in fields waiting to dry out. Molds can lead to mycotoxin production, which can lower feed intake and cause fiber digestibility issues.
“Expect inconsistency in corn silage on top of the lower yields we’ve seen,” said Schmidt. “Consider an additive to help keep the microbial population in the rumen balanced and stable.”