For Release July 23, 2002
Drought Stressed Forages
by Chuck Otte, Geary County Extension Agent
The dry hot weather continues, and even if it has rained, or soon does rain, the damage is already done for many of our crops. We are at the critical time for haying out native grass meadows. That needs to be wrapped up by the end of July. Much of the corn is being harvested for silage or hay and there are concerns about that as well. Additionally, many alternative emergency forages are being considered. Letís just start down the laundry list and touch them all!
Native grass is best cut by mid to late July. Cutting later than August 1st will certainly give you slightly more tonnage, but the quality goes to heck in a handcart and you start to cause long term damage to the grass stand as well. Under the best of conditions, that native grass needs 6 to 8 weeks of regrowth to get it into good shape for the winter and following spring. This assumes that we have decent rainfall after cutting.
If you havenít cut your native hay yet you also need to be leaving a little bit longer than normal stubble when you cut. We generally encourage a 5 to 8 inch cut height to protect plant crowns and the soil. Once the seed stalks start to come up, the plant starts moving valuable nutrients into seed head and seed development. From July 1st to August 1st, crude protein of prairie hay drops from 5 - 6% down to 3 - 4%. At the same time you gain about 400 pounds of yield. Hay that is in that 5 to 6% crude protein will make a minimal foodstuff for cattle. Hay that is below 5% makes good bedding and thatís about it! Cut they hay in a timely fashion so you have something worth feeding!
Drought stressed corn has been the hot topic (so to speak) of late. A lot of corn obviously isnít going to make enough grain to make it worthwhile to leave for grain. Even droughty corn with little or no grain can make good feed. We generally feel that droughty corn silage has about 80% the feed value of good corn silage and we price it about that way. It can have surprisingly good protein. Some tests this year have come in at 10 to 13% crude protein. A lot better than some of this prairie hay weíre putting up.
Of course the one big drawback is high nitrates. Virtually all of the drought stricken corn weíve been testing has had high enough nitrate levels to be of concern. Ensiling will reduce nitrates 40 to 60%. Interestingly, this reduction occurs in the first few days of the ensiling process. Various sources indicate that the nitrate reduction will occur somewhere between 2 and 21 days. It is important not to feed green chop corn directly. It needs to be ensiled.
Feeds with less than 5,000 parts per million (ppm) of nitrates are generally safe for most cattle. Between 5,000 and 9,000 ppm can cause problems and over 9,000 ppm is potentially lethal. There is apparently a bolus or gel available that will inoculate the rumen with bacteria to protect cows up to 20,000 ppm nitrate diets. Iím still trying to find some supportive information on this. Test, feed with caution and dilute high feed sources.
For an emergency forage source you can treat wheat straw with anhydrous ammonia to increase protein and cattle performance. For more reasons than I have time to explain here, this should only be done with wheat straw. I have some excellent handout materials on this process so contact me for that information. This is the kind of year that causes us to value each and every forage source. Letís not panic however, but go into this situation with eyes open and aware of potential problems and potential opportunities.
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