Early Corn Silage and Late HCSAs
At the beginning of my dairy/field crops Extension career, in 1973, I learned that ag educators can’t expect to have answers to all questions farmers might ask – but with some effort they can usually find experts to answer those questions for them. That said, I contacted Sarah Fessenden, forage business development manager at Dairy One Laboratory in Ithaca. On Sept. 9, I wrote, “In the past you have answered many of my forage testing questions. And I’ve taken your answers and incorporated them into my weekly Crop Comments column in Country Folks. I receive your newsletter routinely but would like your earliest possible assessment of the ongoing corn silage – and fresh corn forage – harvest based on Dairy One Lab results. Look forward to hearing from you.”
On Sept. 13, Sarah replied, “Great to hear from you. We haven’t pulled any trends yet for the corn silage coming in; sometimes the customers don’t label it and we aren’t able to distinguish the fresh from fermented. I’ve been doing some dry downs across NY and gathering dry matter and starch data. A lot of the corn in NY is looking affected by drought – short and lower starch levels due to less water during growing. Some areas have had to harvest early with whole plant dry matter increasing. There has been a bit more rain in other areas, raising the whole plant dry matter; however, I think this is a little bit of a red herring and the cobs won’t have much more space to fill out. Overall, likely lower yields and lower starch/energy values. I have one final location scheduled for next week. I can send you some of the data from next week once them get it compiled.”
As I get more information from her, I will share it, since I believe she (perhaps better than anyone else) has her “finger on the pulse” of the late summer/autumn forage harvest situation in the Northeast.
Switching gears, let me tap into Tom Kilcer’s online newsletter for September. Kilcer is a Certified Crop Advisor who I met during our shared county agent days back in the 1970s. His newsletter is “Advanced Ag Systems”; his website (where one finds his monthly newsletters) is advancedagsys.com. His motto is “It is the crops that feed the cows that make the milk which creates the money.”
I’ll hit high spots of what Tom wrote, dealing primarily with ripening sorghums. (Sorghums can be classified as hot climate summer annuals (HCSAs), along with sudangrass, sorghum/sudangrass hybrids and millets. All HCSAs are in the C-4 grouping, along with corn and sugarcane. C-4 means that their “body” tissues consist of four-carbon modules. This trait – without me getting too technical – means that member plants are much more efficient at conserving moisture than is the case with non-C-4 species.)
Kilcer said that more farms are growing sorghum or sorghum species for the first time. Its proper harvest timing is very different from that of corn silage. Sorghums can be a wetter, high-sugar, low-starch forage. In a properly balanced ration, sorghum can produce the same milk at potentially less cost than corn. Chopping sorghum with a short length of cut, and worse, processing, will produce forage the consistency of applesauce – not beneficial to good fermentation, high milk components or preserving nutrients (lost leachate is 100% digestible). The good news is that there are steps to take to maximize results and minimize potential problems.
He stated that their replicated research supported by the New York Farm Viability Institute examined various harvest stages of brown mid-rib (BMR) sorghum. The results were analyzed by Dr. Larry Chase using the Cornell Net Carbohydrate and Protein Systems model. They discovered that for seeded type sorghum, the potential milk increases from the boot stage as the fertilized seed heads started filling. The milk potential decreased as they compared parts of the seed head, going from the tip of the seed head, just starting soft dough, to soft dough halfway down the head. This is because at the soft dough stage there are significant decreases in fiber digestibility of the whole plant where a lot of energy is stored. This, in turn, is compounded by the loss of energy in hard, undigestible seeds. Thus, waiting for matured grain can decrease milk production.
For sorghum species, the length of cut the chopper is set at is critical. Miner Institute research on effective fiber and feed quality found that as forage quality decreases, the shorter the length of cut, the greater milk production from poorer forages. They found that the reverse is true for highly digestible forages such as flag leaf triticale and BMR sorghum species. The smaller they’re chopped, the faster they’re flushed out of the rumen before the cow “enjoys” the full extent of digestion.
Quoting Kilcer again: “Larger particles will stay entrained in the rumen mat until the rumen bacteria extract the majority of the nutrient components. The other problem with chopping these silages fine is it increases the number of plant cells cut open and, especially if processed, will release hundreds of gallons of leachate. Leachate, besides making a smelly mess, removes the most digestible part of the plant. Each additional cut – shorter chop length – opens more plant cells for the liquid to run out. We harvested at 1/2-, 3/4- and 1.14-inch length of cut, with no processing. As long as we did not process, we had excessive liquid (leachate) from the 1/2- – but not the 3/4- and 1.14-inch (cut setting).”
Kilcer and I firmly believe that 2022 was a particularly good year for growing sorghum, sudangrasses and their hybrids because there were so many days in our region with temperatures peaking in the 90s; corn does not benefit from temperatures over 85º. Sorghum has been shown to keep performing with heat pushing 105º. It’s not surprising since the crop originated in sub-Saharan Africa.