R. S. Adams, Emeritus, Professor
of Dairy Science
Penn State University
Drought stricken soybean plants can be used as a forage crop.
Allow plants to mature as much as possible before harvesting.
Some pod or bean development enhances feeding value of plants
harvested either as hay or silage. Soybean forages are high
in calcium (about 1.3% on a DM basis). For this reason it
should be avoided as the major forage for dry cows.
If ensiling, it is important to ensile
before plant moisture drops below 60-65%. If possible, mix
soybeans with other forages, preferably during ensiling, to
enhance their palatability. If plants are high in moisture
and lack pod or bean development, add 100-200 lb of ground
grain per ton when direct-cutting rather than wilting to 60-65%
moisture.
Stems are not very palatable, and if animals
have the opportunity, they will sort them out. Chopping hay
and feeding it in a total mixed ration (TMR) will help prevent
sorting, and stretch forage supplies.
If soybean forage contains substantial
amounts of developed beans, reduce the amounts of other fats
and oils in the ration, or the ration may be too laxative.
Also, it may be difficult to dry down pods for hay if beans
are too well developed. Soybeans can be pastured. If cows
are removed before all stems are eaten, there may be regrowth.
The table below gives some estimates of
the nutrient content of soybean forage on a dry matter basis:
Expected Nutrient Content of Soybean Forage
| Stage
of Maturity |
CP
% |
ADF
% |
Nel
|
Ca
% |
P
% |
Mg
% |
| avg silage, hay |
17.7 |
35 |
.54 |
1.25 |
.49 |
.34 |
| avg hay |
16.5 |
35 |
.55 |
1.20
|
.47
|
.32 |
| mid bloom |
17.8 |
35 |
.57 |
1.25 |
.49 |
.34 |
| seed developing |
17.5 |
35 |
.59 |
1.20 |
.47 |
.32 |
| seed dough
stage |
16.8 |
35 |
.61 |
1.15
|
.45
|
.30 |
The dry matter content for average silage
is 28%, while that for hay is 88%. Test soybean forage or
mixed forages containing soybeans to enable proper ration
balancing.
Precautionary note:
You need to consider some of the herbicide restrictions. If
you look on page 118 in the 1995-1996 Agronomy Guide, you
will fine Table 6-17. Feeding restrictions on soybean forage
and grain. Unfortunately with few exceptions, most soybean
herbicides do not allow feeding the soybean plant as forage.
The exceptions are Basagran, Lexone, or Sencor, and Lasso/MicroTech.
I suspect that the reason that most of the newer herbicides
donUt allow this use is because the ingredients simply never
received a forage tolerance. Soybeans are not typically harvested
as forage and it costs the manufacturer a great deal of money
to conduct tolerance/residue studies. Think about how few
product we have labeled on alfalfa. Although this explanation
may not help, its what on the product use label.
Bill Curran, Asst. Prof. of Weed Science
Agronomy Dept. Penn State
Author: Richard S. Adams, Emeritus, Professor of Dairy Science
Virginia Ishler, Program Assistant of Dairy and Animal Science
324 Henning Building, University Park, PA 16802
(814) 863-3912 |
