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NC Indiana | This info was forwarded to me last night and I thought I would share it with all the questions about what to do with drought corn. Hope it helps!
Recent information on feeding drought stressed corn stalks:
Back in ’88 we did a study with some corn silage made from a field that yielded 6 tons/a of silage and had a corn yield of 6 bu/a. We compared it to the previous year’s silage that we estimated was 175 bu/a. We fed this to a set of steers during a growing phase (silage plus supplemental protein, vitamins and minerals), followed by a finishing phase (silage plus corn and supplement). Cattle during the growing phase on the drought silage ate more and gained faster than the normal silage, but had poorer feed efficiency. BOTTOM LINE: drought stressed corn silage is pretty good feed. Expect drought stressed corn silage to be higher in crude protein (probably because of higher nitrate values) and slightly less energy than normal corn silage.
There are always caveats to everything.
1) We didn’t do this for dairy cows, but I think the growing steer model should be a pretty good indicator of how they will perform.
2) This assumes that the silage is made in the correct moisture range for good fermentation (30-45% DM). Higher moisture can lead to a butyric acid fermentation (sour) and can result in some clostridial growth and maybe listeria – all bad.
3) Nitrates can be a problem, even in silage. I’d like producers to spend a few bucks to get a nitrate analysis before cutting to determine if the cutter bar should be raised or not. Fermentation will remove 40-60% if made correctly. If the plants were high in nitrates before harvest, a second sample before feeding is justified so we can decide how much diluting with other feeds needs to take place to make a safe ration.
4) Small producers that have limited experience with silage probably need to consider having someone in to make an ag bag. If they make a bunker or pile, small producers will not be able to feed fast enough to keep the silage fresh. An ag bag is about 8 foot in diameter and has about 1 ton of silage per foot. When they use a front end loader of skid steer to get it out of the structure, they will disrupt the face and allow air to penetrate deeper into the silage. A pile or bunker will have more exposed surface and it will heat and rot – probably faster than they can feed it. The ag bag only has an 8 foot face and has a much higher probability of staying fresh, especially in small operations.
I have heard, but do not have confirmation of a producer in southern Indiana that made corn hay and killed some cows. That has been my fear (and Bob Nielsen that keeps me awake at night). For those that were in Indy last week for the media event and drought discussion, I raised this issue to the livestock discussion group. Making corn as a hay crop is risky business. Think about a corn bale fed to a set of cows to extend pastures. If cows are hungry, they will eat a big meal when feed is placed in front of them. Also think about the fact that areas of the field will have higher nitrate levels than other areas. If a bale is made in one of the “hot” nitrate areas of the field and fed to hungry cows that are not adapted slowly to a high nitrate feed, you could have a pretty good number of dead cows. Producers might think that the cow will go and graze some weeds or even a bale of old hay they put out, but a hungry cow will probably not think about the fact that she needs to eat a low nitrate feed to dilute the nitrate concentration down. If a producer is going to make corn plant hay, I think it is imperative that they 1) stay away from cutting any corn following a recovery rains (nitrates go up after a recovery rain and then come back down over the next 7+ days). 2) take samples from 3 areas in the field (poorest, next poorest and best) and submit 3 samples for a nitrate test. They have the option of delaying harvest or going around what are the potential “hot” spots. 3) Nitrates do not dissipate during hay dry down – what you start with is what you end up with.
It is imperative for all producers that feed this year’s corn crop as a forage resource to introduce any feed that has the potential of having elevated nitrate concentration slowly. Cows should be filled up on hay and fed a small quanty of suspect feed on day 1. Each day the amount can be increased (over a 10-14 day period) to adapt the rumen to nitrate utilization. Feeds with less than 5000 ppm NO3 can be introduced slowly and become the primary feed resource. Between 5000-10,000 ppm the feed becomes more risky and must be diluted. Over 10,000 the feed is considered toxic and can only be used as a small portion of the diet.
Green chop is also dangerous. Chop only what will be fed immediately. NEVER let it sit on a wagon overnight. The plant tissues are still alive and there will be conversion of nitrate to nitrite which is about 10X more deadly than the original nitrate. Green chop is a tick safer than making hay because it will be layered in the wagon during harvest and it will get mixed with the silage wagon beaters when offloaded. By nature, we would expect some blending and some dilution to take place before it id fed. Again, the operative word is transition. Start by introducing small quantities to cows that are full and keep cows full as the amounts of high nitrate feeds are gradually increased over a 10-14 day period.
The sorghum family of forages and the millets can also accumulate nitrates. The same rules apply as drought stressed corn.
Ron
Ronald P. Lemenager, PhD, PAS
Beef Nutrition and Management
Charter Diplomate, American College of Animal Nutrition
Department of Animal Sciences
915 W. State Street
Purdue University
W. Lafayette, IN 47907-2054
Cell: 765-427-5972
Office: 765-494-4817
Email: [email protected]
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Info on drought corn for silage and hay
