A3O-Lancaster Farming, Saturday, September 12, 1992
Foraging
Around fl
John E. Baylor
Forage Specialist (Retired)
Penn State University
SILO FILLING TIME -
IT’S HERE
Silage that nice smelling,
succulent forage preserved by a
controlled anaerobic (in the ab
sence of air) fermentation of green
forages. It can be made from al
most any forage crop including
perennial legumes and grasses,
sorghums and small grains. Even
crops such as sunflowers, soy
beans and peanut and pea vines
have been ensiled successfully.
But com is the leading crop
used for silage. And based on all
of the knowledge we have, when
the land and climate are suited for
com, whole plant com silage pro
duces more digestible energy per
acre than any other feed crop.
What makes com such a big hit
for silage? Here are just a few rea
sons:
• Ensiling the entire com plant
increases the amount of energy
per acre from 40 to 50% compared
to harvesting only the grain.
• Com is high in sugar and
starch which makes it relatively
easy to preserve by ensiling.
• It’s a relatively high energy
feed, and while it is low in protein,
it’s an excellent complement for
high protein but lower energy al
falfa and other legume forages.
• Com silage production, har
vesting, storage and feeding can
be highly mechanized and because
of its good ensiling characteristics
it can be stored in a variety of
structures with relatively low loss
es when properly harvested and
processed.
Silo filling starts in late spring
with winter grains. It gets a big
boost in mid to late May with first
cutting of alfalfa and alfalfa-grass
mixtures. It continues all summer
with later cuttings of alfalfa, other
legumes and grasses, oats, sum
mer annuals and other crops in
cluding sorghums.
BUT silo filling is in full swing
right now when one out of every
three to four acres of com grown
in Pennsylvania will be ensiled.
HYBRIDS FOR SILAGE
At this time of year there’s no
need to spend much time talking
about hybrids for silage. Suffice it
to say that as com breeders and
animal nutritionists take a closer
look they now know that when it
comes to nutritional value for live
stock all com hybrids are not
alike. And it’s true that several re
search studies suggest that the
feed value or quality of whole
plant com silage may not be as
closely related to grain content as
we have always assumed.
Nevertheless until researchers
can zero in closer on their findings
we can still say with confidence
that a hybrid well suited for grain
production in your area will also
be excellent for com silage.
CULTURAL PRACTICES
Now isn’t the time to go into
detail on cultural practices for
com grown for silage either. But
we can, and should say that if com
harvested for silage is to be a high
quality forage in your livestock ra
tion it must receive top manage
ment during production, harvest
ing and storage.
For example, many studies
have shown that increasing your
plant populations improved both
grain and forage yields with no
change in silage quality. Thus, the'
thumb rule that populations for
silage in your area should be 2000
to 4000 plants per acre higher than
for grain is still a good one.
Also, we know the importance
of a "balanced” soil fertility pro
gram for top production. But fer
tilization can also affect the fer
mentation process. In fact, recent
Wisconsin studies indicate that
even greater attention must be
paid to nutrient balance when
crops are to be ensiled.
MATURITY AT HARVEST
Now is the time to talk about
when to harvest your com crop for
silage. Because stage of maturity
or moisture at harvest time does
have a significant influence on sil
age yield and quality.
I won’t go into all of the details,
but based on neutral detergent fib
er (NDF) and acid detergent fiber
(ADF) values, as well as whole
plant yields, for best quality silage
stored in conventional silos har
vesting when com is 62 - 68%
moisture is a good choice. It
should be slightly higher when
stored in horizontal silos and
slightly lower for limited oxygen
silos. This stage, approximately
full dent, say Penn State workers,
is reached at a minimum of 40 to
50 days after com has silked. The
kernel milk line should be near
50%, and the kernel black layer
will not have formed. Frequently
when com reaches physiological
maturity total dry matter content is
too high, proper fermentation may
be a problem and feed quality may
be sacrificed.
LENGTH OF CHOP
Now is also the time to talk
about fineness of chop. And while
researchers may not agree on de
tails a good compromise on chop
ping seems to be 3/8 to 3/4 inch
theoretical length of cut for com
harvested at the recommended
stage of maturity. This will assure
adequate packing and best use of
silo space without sacrificing fi
ber. If com is harvested at more
mature stages, or when the whole
g MAK.IT DOESABODY GOOD.
MIDDLE ATLANTIC MILK MARKETING ASSOCIATION. INC
plant contains more than 40% dry
matter, a finer cut may be desir
able.
And don’t ignore the other rules
of good silage making. Fill your
silo as rapidly as possible. Distri
bute the ensiled material as uni
formly as possible. And do what is
necessary to insure a good pack
and keep oxygen out to reduce
mold damage and spoilage losses.
Compared to most forages com
is considered a natural silage crop.
And researchers can’t agree on the
value of silage additives for this
crop. Nevertheless many now feel
that treating com silage with a
proven silage additive may be
beneficial, especially if conditions
at ensiling are less than ideal.
SORGHUM FOR SILAGE
Because of our enthusiasm for
com as a silage crop, little is said
about when to harvest forage sor
ghums for silage. It’s generally
true that under the best growing
conditions the yield of feed nutri
ents per acre of forage sorghum is
only 90 to 95% that of com. And
the feed value of sorghum silage is
only 85% or so of that of com sil
age. Still forage sorghums are
known to be more drought tolerant
than com. And growing forage
sorghums on droughty soils may
be preferable to com.
If you are growing sorghums
for silage this year and hope to
maximize production and quality,
harvesting at the soft to medium
dough stage is your best bet. And
follow the same silage-make rules
for sorghum as you do for com.