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It’s been a wet, cool spring, but one thing you shouldn’t do is use Roundup to increase dry matter.

May 11, 2021

4 Min Read
Tractor tedding winter forage
TAKE TIME TO TED: Tedding your winter forage is an important part of getting it dried the same day. Make sure you use a wide swath to get as much sun as possible. Farm Progress photo

There has been much concern and questions over harvesting winter forage — rye or triticale — this spring. 

If you’re in Pennsylvania or Ohio, your crop is likely already harvested or is well past dairy forage potential. For New York; much of New England; and Michigan, Wisconsin, Minnesota and lower eastern Canada, rye is at or approaching peak quality or yield. Triticale is about a week behind. 

If a sunny day opens, you need to grab it if the forage is close to flag leaf.

The good news is that cool-to-cold temperatures will help maintain the high digestibility of the forage. The cloudy weather also keeps it from growing and maturing.  

Even if cold temperatures continue past flag leaf stage, we have found that the digestibility of the forage is maintained through early head emergence. So, if the head is out, not all is lost because of cold temperatures.

You need to use all the techniques of wide-swath, same-day haylage to get some harvested as each of the drying windows opens and closes rapidly. You probably won’t get everything done in a day; what you mow today goes in today.

Here are four tips to ensure success:

1. Mow early with a swath greater than 80% of cutter bar. Give it two hours of sun and then ted it to bring the lower layers into the sun. If it’s a partly cloudy day, you may need a second tedding before windrowing and chopping. If it’s an overcast, damp day, this will not dry, and you are stuck.  

Cool temperatures reduce the rate of photosynthetic drying and slow the process. That said, we have measured much higher temperatures in wide swath than in narrow for the same weather conditions.

2. Use a homolactic inoculant. You need everything in your favor to get it to ferment properly. Part of the challenge is that the lack of sunlight will also leave the forage in a sugar deficit stage. Thus, you are already limited on the substrate for rapid fermentation. 

Don’t further compromise it by just letting whatever garbage is floating in the air do the fermentation. With enough plant sugar and homolactic bacteria, we were able to ferment forages (sorghum) as wet as 17% dry matter with no butyric and a silage pH of 3.6. We don’t want to harvest that wet a forage, but this year we may not have a choice.

The question comes if there is a week of very cloudy weather and you mow on the first nice day, will there be enough substrate or will the plant be in a sugar deficit? A full-width swath can help offset some of that.

3. Don’t chop fine. With the cool and cold temperatures, the forage has very high neutral detergent fiber digestibility. If you chop it fine, you will make low-effective fiber soup out of it, have a huge amount of leachate and nutrients running out of the silo, and will have very rapid rumen passage before you get the full extent of digestion. 

We have chopped a similar wet product (sorghum) at three-quarters to 1 inch and dry matters below 25% and did not have any leachate issues.

This is a tough year for winter forage harvest. You are farming and no matter what crop you grow, at some point you will get some adverse weather.  

4. Don’t use Roundup to increase dry matter. There are stories going around about spraying Roundup before harvest to increase dry matter and stop quality loss. 

I tested this idea back in 2011 and again in 2012. I went back and dug out the data. It did not stop the plant from maturing. It took a week before it showed a dry matter difference, and at that point, it was not a significant difference, but the crop was a week older.

It also lodged significantly while the untreated control did not. 

The biggest issue with this is that it is not legal to do as it is not on the label. If you’re caught, your forage supply could be condemned, and your milk might not be shipped. Even worse, if word got out to consumers about this, it can have an adverse effect on all dairy sales. 

Don’t use Roundup. It is stupid, counterproductive and illegal.

Kilcer is a certified crop adviser in Kinderhook, N.Y.

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