| W. P. Weiss, Department of Dairy Science, Ohio Agricultural Research and Development
Center, Wooster, and W. L. Shockey, Center
for Agriculture, Natural Resources, and Community Development, WVU Extension Service,
Preston County 8/1999
Corn Plants
- Ensiled drought-stressed corn silage is a good feed if supplemented properly.
- Dry matter yield and energy yield per acre will be lower than that of normal corn
silage.
- Drought-stressed corn is usually higher in crude protein and lower in energy.
- Type of crude protein is also different. Normal corn silage has about 5% true protein
and 3% nonprotein nitrogen on a dry matter basis (DMB). Drought-stressed corn silage may
have about 5% true protein and 7% nonprotein nitrogen, DMB. This may limit the amount of
added nonprotein nitrogen (NPN) the cow can use efficiently.
- The biggest concern is energy. You must feed more grain with drought-stressed corn
silage because of its low energy value. A general rule--12 parts wet drought-stressed
silage plus 1 part corn grain is equal to normal corn silage. Energy content of
drought-stressed corn may vary tremendously so first have it analyzed and then determine
how much grain is needed.
Example:
A test shows that drought-stressed corn silage has an energy value of 60% total
digestible nutrients (TDN). Normal corn silage has an energy value of 70% TDN. Corn grain
has an energy value of 87% TDN. If your ration had 50 pounds of non-drought-stressed corn
silage and the corn silage was 40% dry matter, you would be supplying 14 pounds of TDN.
Drought-stressed corn silage would provide only 12 pounds of TDN. To make up the
additional 2 pounds of TDN, you would need to feed 46.5 pounds of corn silage and 3.5
pounds of corn grain.
- Because drought-stress conditions can vary from farm to farm, it is recommended that you
test all drought-stressed corn silage so that feed is used most efficiently.
Alfalfa
- Drought-stressed alfalfa yields are lower, but quality is higher compared to
non-drought-stressed alfalfa harvested at the same stage of maturity.
- Let alfalfa stand until mid- to full-bloom stage to gain maximum dry matter yields. Once
the plant has reached full bloom, dry matter yield will not increase, even if rain occurs.
Harvest no later than full-bloom stage of growth.
Grasses
- Like drought-stressed alfalfa, yields are lower.
- Drought-stressed grasses contain higher levels of fiber and lower levels of protein and
energy. To maximize dry matter yields, drought-stressed grasses should be harvested at the
head stage of growth. Little dry matter increase is observed after the heading stage, but
quality begins to decrease rapidly.
- As with all drought-stressed forages, analyze grasses before feeding.
Programs and activities offered by the West Virginia University
Extension Service are available to all persons without regard to race, color, sex,
disability, religion, age, veteran status, political beliefs, sexual orientation, national
origin, and marital or family status. Issued in furtherance of Cooperative Extension work,
Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture.
Director, Cooperative Extension Service, West Virginia University. |
