The author is dairy nutritionist and technical services adviser with Vita Plus.
What a fall many of us had!
We approached fall harvest with wetter-than-normal fields and were prepared for that. We were not prepared for the heavy rains that occurred during harvest.
Corn matured quickly, resulting in drier-than-normal corn silage. Corn continued to dry down, very fast in many cases, as we waited to get back into the fields. We had to use dump carts and pull trucks through the fields, but at least we were chopping.
I give credit to the advent of shredlage for putting a lot of focus on kernel processing the past few years. Everyone has stepped up, putting greater emphasis on improved kernel processing. The advancements allow us to let corn mature longer, enhancing the starch content of corn silage. This year’s crop took that to the extreme, so we had to monitor kernel processing closely throughout harvest.
I will give up length of cut to ensure good kernel processing. Shortening length of cut allows the kernel processor to work easier. During most years, we stay close to 1 inch or longer theoretical length of cut (TLOC) and move closer to 0.75 inch as the corn dries. This year, we started close to 1 inch, but dry corn forced us to 0.5 inch TLOC for adequate kernel processing.
Another change we made on many farms was to chop higher to compensate for the decline in fiber digestibility that is associated with harvesting corn at a later stage of maturity. The lowest portion of the stalk contains the least digestible fiber. Traditional chopping heights have been in the 6- to 8-inch range.
This year, many of us chopped at heights of 12 inches and up to about 18 or 20 inches. We ended up with a silage that has less undigestible fiber and more starch. Research has shown 5 percent improvements in the amount of fiber digestibility and starch. This silage will be about 2 percentage points drier because it contains a higher percentage of ear, which is drier than stover.
In some cases, we decided to chop more acres of higher chop corn silage versus switching to snaplage or high-moisture corn. The corn was too dry to make good snaplage, and it was faster to continue chopping than switch to snapping or combining.
Pack, pack, pack!
We emphasize packing every year, but this year it was especially important. Drier corn silage is harder to pack and squeeze out air. This is true for any type of storage: uprights, bags, piles, and bunkers. We had the most opportunity to improve packing on piles and bunkers.
Time and weight are critical factors for proper packing. During ideal chopping conditions, we can overwhelm pack tractors with too much silage too fast. That was not as big of an issue this year. Field conditions made trucks and wagons wait for dump carts or to be pulled through the field. That allowed plenty of time for pushing and packing. Packing tractors were only stressed when more choppers were brought in to get the job done.
Can a shredlage-type of material be easier to pack?
Research has not proven it, but I believe it can, especially with drier corn silage because we have vertically shredded pieces of stalk instead of horizontally cut cylinder pieces of stalk.
Squeeze a stover cylinder between your fingers. It will go back to its original shape if it is dry and spongy. A shredded stalk does not have as much ability to expand after being compressed, resulting in less oxygen remaining in a shredlage-type of silage.
Keep fermentation in mind
The first phase of fermentation is the aerobic phase, which will continue until all of the oxygen is eliminated. The more oxygen present, the longer the aerobic phase continues and temperatures rise inside the silage.
The “bad” oxygen-loving organisms, including yeasts and molds, have more of a chance to thrive the longer this phase continues, creating an unstable pile of silage and contributing to a loss of feed quality. Thoroughly packing, eliminates as much oxygen from the silage as possible, before fermentation even begins and shortens this phase.
The second phase of fermentation is the anaerobic phase that begins once oxygen is depleted. Lactic acid-producing bacteria are active during this phase. Acids are produced, pH drops, and the silage is preserved.
Moisture is critical during this phase. We recommend adding a reputable lactic acid-producing inoculant regardless of the moisture; however, it is more critical with dry corn silage because fewer of these active, naturally occurring bacteria are present.
The problem with this year’s crop was that corn silage became so dry (between 45 and 50 percent dry matter) that we started to question the ability of inoculants to even help fermentation. We continued to apply inoculant because we needed to reduce as much risk as possible to give us the best opportunity for stable silage in storage.
How will it feed?
The answer depends on how you did with the discussion points in this article.
Are the mature kernels processed well? Processing improves surface area for rumen bacteria to access starch. Poorly processed kernels will go through the cows, having a better chance to feed turkeys than rumen bacteria. Do you have several months of carryover from the 2015 corn silage crop? It takes time for starch digestibility to improve because fermentation breaks the prolamin protein/starch linkages, giving rumen bacteria faster access to the starch.
Testing manure starch can help determine how much starch is passing through the cows, and we can make up for some of the starch. You will need room in the diet for extra corn or by-products, so the forage level will have to be reduced. Watch what manure is telling you. Corn passage to the intestines, combined with lowering forage, can lead to digestive upsets.
We will monitor molds, yeast, and mycotoxins in this year’s corn silage. The longer the crop stood in the field, the more opportunity yeasts and molds had to grow. These issues will be hard to fix. Test the silage and work with your nutritionist to determine the best strategy.
We may have challenges with the face and top surfaces of piles and bunkers. You have to take enough off the face of all storage structures. Dry corn silage could have stability issues and will heat due to yeast and molds if too little is removed from the face.
Ending with dry corn silage on the top of piles makes it difficult to remove oxygen from the top layers. Oxygen will be able to penetrate the top layers much quicker once the pile is opened. Do not remove excess plastic when opening more corn silage and maintain a line of tires or sand bags along the plastic edge to prevent as much oxygen as possible from getting under the plastic.
I have successfully fed well-processed, 45 to 50 percent dry matter corn silage in bags. The keys were that it was packed well, it had plenty of time to ferment, and we fed a large amount off the face every day. The total mixed ration will be drier, so watch for excessive sorting.
Lastly, stay safe. Be careful near silage faces. It was difficult to pack drier corn silage, especially in the top layers, so there may be more potential for face collapses. Regardless of the challenges this year’s crop brings, we want to make sure we are able to take them head on.