• TABLE OF CONTENTS
HIDE
 Introduction
 Baleage-making systems
 Balers
 Stretch-plastic wrapping machi...
 Silage bale handling equipment
 Conclusions






Group Title: Florida Cooperative Extension Service circular 1071
Title: Equipment for preserving forage as round-bale silage
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00014570/00001
 Material Information
Title: Equipment for preserving forage as round-bale silage
Series Title: Circular
Physical Description: 7 p. : ill. ; 28 cm.
Language: English
Creator: Cromwell, Richard P
Kunkle, William, 1947-
Chambliss, C. G ( Carrol Gene )
Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
Publication Date: [1994]
 Subjects
Subject: Forage plants -- Silage -- Southern States   ( lcsh )
Forage plants -- Harvesting -- Southern States   ( lcsh )
Silage machinery   ( lcsh )
Silage -- Handling -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: R.P. Cromwell, W.E. Kunkle and C.G. Chambliss.
General Note: Title from caption.
General Note: "April 1994."
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00014570
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 001931446
oclc - 30845695
notis - AKA7501

Table of Contents
    Introduction
        Page 1
    Baleage-making systems
        Page 2
        Single-bale bags
            Page 2
        Multiple-bale plastic tubes
            Page 2
        Stretch-wrap plastic
            Page 3
    Balers
        Page 4
    Stretch-plastic wrapping machines
        Page 4
        Page 5
    Silage bale handling equipment
        Page 6
    Conclusions
        Page 6
        Page 7
Full Text
/0/


UNIVERSITY OF

SFLORIDA


Circular 1071
April 1994


Institute of Food and Agricultural Sciences




Equipment for Preserving Forage as Round-Bale Silage1


R.P. Cromwell, W.E. Kunkle and C. G. Chambliss2

Forage crops such as grasses and legumes grow
rapidly during the warm humid summer months in
Florida and throughout the southeast. Excess forage
produced during this peak growth period is often
preserved as hay to be fed to livestock during the
winter when forages are in short supply. Preserving
the forage as hay is made very difficult because the
chances are slim for having 2 to 4 days of weather
suitable for drying the forage to the 15 to 20 percent
moisture level needed for safe, long-term storage.

So, in many cases the crop is harvested when the
weather allows harvesting rather than when the forage
is at its nutritional peak and would make quality hay.
Because of the difficulty in consistently making quality
hay in humid climates, some forage producers store
their excess forage as silage because it can be
harvested when the crop is ready, not when the
weather permits. The longest time that a forage crop
must dry in the field before being harvested is
approximately 4 hours for grasses and 6 hours for
legumes. Therefore, silage can be harvested in all but
the worst weather conditions.

Preserving forage as silage is a process that has
been practiced for many years. Most silage is
preserved in upright or horizontal (bunker) silos. The
forage is usually chopped into small pieces so that it
will pack tightly in the silo. The packing process forces
most of the air from the forage mass so that the
anaerobic bacteria (microorganisms that live in an
oxygen free environment) can produce the organic


1. This document is Circular 1071, Florida Cooperative Extension
Publication date: April 1994.


acids needed to preserve silage. When enough acid is
produced to drop the pH of the silage into the 4+
range, the silage will remain a palatable feed for a
long time (years). Bulletin 240, Silage Harvesting
Equipment and Storage Structures, is a publication
offered by the Cooperative Extension Service of the
University of Florida that covers many aspects about
making silage from chopped forage.

The primary disadvantage of making silage from
chopped forage is the cost of the equipment used to
chop and haul the forage to the silo, and the cost of
the silo structure. These costs limit this type of silage
to relatively large cattle feeding and dairy operations.

In recent years considerable research has been
conducted to perfect a more economical system for
making silage from round bales of relatively wet grass
or legumes. In general, the quality of the silage thus
produced has been less consistent than that produced
from the conventional silage-making methods using
chopped forage. However, the results have been
encouraging enough to recommend the method to
cattlemen with some precaution.

Having the flexibility to make round-bale silage
when the weather will not allow harvesting the forage
as hay could enable cattlemen in the humid climate of
the southeast to produce quality feed more
consistently than is possible when producing dried hay
exclusively. The additional cost of the equipment
needed for making round-bale silage over the cost of


Service, Institute of Food and Agricultural Sciences, University of Florida.


2. Authors are Associate Professors of Agricultural Engineering, Animal Science, and Agronomy, Cooperative Extension Service, Institute of Food
and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national
origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean






Equipment for Preserving Forage as Round-Bale Silage

equipment for making round bale hay ranges from
virtually zero to approximately $15,000-- depending
on what system is used for making the silage.

All methods for making round-bale silage (or
baleage) require some type of airtight plastic envelope
for storing the bale so that anaerobic bacteria can
bring about the fermentation needed to preserve the
forage bale. What follows are descriptions of those
baleage-making systems researched at the University
of Florida.


Page 2


Multiple-Bale Plastic Tubes

Bales were stored in long tubes (Figure 2) holding
up to 20 bales, depending on bale width. This second
system was not as costly as the single-bag system, but
was dropped from the research program because any
undetected hole (often unavoidable) results in all of
the bales in the tube being spoiled, not just one bale
as would happen in the single-bag system.


BALEAGE-MAKING SYSTEMS


Single-Bale Bags

In the first system, rolls were individually stored
in plastic bags (Figure 1), gathered at their open end
and sealed with twine. This method was publicized in
many of the popular farm publications, but it was
eliminated from the research program after a few
years because the object of making silage with round
bales was to make relatively economical silage. Using
individual bags for storage proved to be a costly
system because it required a lot of labor, and plastic
bags used for storing the bale were expensive.

The bags, containing a single bale that weighed
approximately 1600 to 2000 pounds, cost $6 to $8
dollars apiece. Each bag was usually good for a year's
service, regardless of how careful workers were when
loading and unloading the bale into the bag. A forage
producer who stored more than a minimum number
of bales as baleage would find it more economical to
build a silo and buy the equipment for making silage
from chopped forage than to use the bag system.


Figure 1. Silage bales in individual bags.
I >\

7 \V
I 3D 7
107^


Figure 2. Silage bales in long plastic tube.
Both these systems had the advantage of not
requiring any costly equipment beyond that needed for
making round-bale hay. The single-bag system
required a spear mounted on a front- end loader
(Figure 3) or a three-point lift of the tractor (Figure
4) to lift the bale so the bag could be slipped over it.


Figure 3. Spear on a front-end loader loads bales in bags or
tubes.

The spear in Figure 3 is normally used to load
bales onto a truck or trailer, so it is not required
specifically for silage making. However, a spear used
for hay making may have to be reinforced to pick up
the heavier silage bales.






Equipment for Preserving Forage as Round-Bale Silage

equipment for making round bale hay ranges from
virtually zero to approximately $15,000-- depending
on what system is used for making the silage.

All methods for making round-bale silage (or
baleage) require some type of airtight plastic envelope
for storing the bale so that anaerobic bacteria can
bring about the fermentation needed to preserve the
forage bale. What follows are descriptions of those
baleage-making systems researched at the University
of Florida.


Page 2


Multiple-Bale Plastic Tubes

Bales were stored in long tubes (Figure 2) holding
up to 20 bales, depending on bale width. This second
system was not as costly as the single-bag system, but
was dropped from the research program because any
undetected hole (often unavoidable) results in all of
the bales in the tube being spoiled, not just one bale
as would happen in the single-bag system.


BALEAGE-MAKING SYSTEMS


Single-Bale Bags

In the first system, rolls were individually stored
in plastic bags (Figure 1), gathered at their open end
and sealed with twine. This method was publicized in
many of the popular farm publications, but it was
eliminated from the research program after a few
years because the object of making silage with round
bales was to make relatively economical silage. Using
individual bags for storage proved to be a costly
system because it required a lot of labor, and plastic
bags used for storing the bale were expensive.

The bags, containing a single bale that weighed
approximately 1600 to 2000 pounds, cost $6 to $8
dollars apiece. Each bag was usually good for a year's
service, regardless of how careful workers were when
loading and unloading the bale into the bag. A forage
producer who stored more than a minimum number
of bales as baleage would find it more economical to
build a silo and buy the equipment for making silage
from chopped forage than to use the bag system.


Figure 1. Silage bales in individual bags.
I >\

7 \V
I 3D 7
107^


Figure 2. Silage bales in long plastic tube.
Both these systems had the advantage of not
requiring any costly equipment beyond that needed for
making round-bale hay. The single-bag system
required a spear mounted on a front- end loader
(Figure 3) or a three-point lift of the tractor (Figure
4) to lift the bale so the bag could be slipped over it.


Figure 3. Spear on a front-end loader loads bales in bags or
tubes.

The spear in Figure 3 is normally used to load
bales onto a truck or trailer, so it is not required
specifically for silage making. However, a spear used
for hay making may have to be reinforced to pick up
the heavier silage bales.






Equipment for Preserving Forage as Round-Bale Silage

equipment for making round bale hay ranges from
virtually zero to approximately $15,000-- depending
on what system is used for making the silage.

All methods for making round-bale silage (or
baleage) require some type of airtight plastic envelope
for storing the bale so that anaerobic bacteria can
bring about the fermentation needed to preserve the
forage bale. What follows are descriptions of those
baleage-making systems researched at the University
of Florida.


Page 2


Multiple-Bale Plastic Tubes

Bales were stored in long tubes (Figure 2) holding
up to 20 bales, depending on bale width. This second
system was not as costly as the single-bag system, but
was dropped from the research program because any
undetected hole (often unavoidable) results in all of
the bales in the tube being spoiled, not just one bale
as would happen in the single-bag system.


BALEAGE-MAKING SYSTEMS


Single-Bale Bags

In the first system, rolls were individually stored
in plastic bags (Figure 1), gathered at their open end
and sealed with twine. This method was publicized in
many of the popular farm publications, but it was
eliminated from the research program after a few
years because the object of making silage with round
bales was to make relatively economical silage. Using
individual bags for storage proved to be a costly
system because it required a lot of labor, and plastic
bags used for storing the bale were expensive.

The bags, containing a single bale that weighed
approximately 1600 to 2000 pounds, cost $6 to $8
dollars apiece. Each bag was usually good for a year's
service, regardless of how careful workers were when
loading and unloading the bale into the bag. A forage
producer who stored more than a minimum number
of bales as baleage would find it more economical to
build a silo and buy the equipment for making silage
from chopped forage than to use the bag system.


Figure 1. Silage bales in individual bags.
I >\

7 \V
I 3D 7
107^


Figure 2. Silage bales in long plastic tube.
Both these systems had the advantage of not
requiring any costly equipment beyond that needed for
making round-bale hay. The single-bag system
required a spear mounted on a front- end loader
(Figure 3) or a three-point lift of the tractor (Figure
4) to lift the bale so the bag could be slipped over it.


Figure 3. Spear on a front-end loader loads bales in bags or
tubes.

The spear in Figure 3 is normally used to load
bales onto a truck or trailer, so it is not required
specifically for silage making. However, a spear used
for hay making may have to be reinforced to pick up
the heavier silage bales.






Equipment for Preserving Forage as Round-Bale Silage


Figure 4. Three-point lift-mounted tool for loading bales in
bags or tubes.

Systems that store bales in tubes used either an
inexpensive aluminum cylinder (Figure 5) that served
as a jig to aid in manually inserting the bales into the
tube or a piece of equipment that loaded the bales
into the tube with the aid of an hydraulic ram (Figure
6). The bale-loading equipment using the hydraulic
ram cost approximately $4000, which is a significant
amount, but not essential to the silage making process.


Figure 5. Aluminum cylinder used to hold plastic tubes.


Stretch-Wrap Plastic

The round-bale silage-making system that appears
to offer the most promise for success uses a stretch-
wrap plastic to encase the bale. The silage produced
from the stretch-wrapped bales was consistently better
than that produced with the bag and tube systems
described earlier. The stretch-wrap system applies four
overlapping layers of 20-inch-wide plastic 1 mil


Figure 6. Hydraulic ram-operated device for loading bales in
a tube.

(0.001") thick. This is done with a special piece of
equipment: a plastic-wrapping machine costing from
$8000 to $14000; a sizeable investment. In spite of
this, most forage producers considering round-bale
silage would probably be better off buying the
wrapping machine rather than using the bag or tube
systems described above.

The cost of the four layers of plastic is in the
range of $3 to $4 (1991 prices) per bale, but this is
considerably less than the average of $7 per bale for
the bag system and about the same as the plastic cost
per bale for long-tube storage. The greater initial cost
of the stretch-wrap system (due to the cost of the
machine) would be recaptured by the savings from
lower plastic costs and better quality silage when
compared to the individual bag system.

Compared to long-tube storage, the stretch-wrap
system has to recapture its greater cost from higher
silage quality alone, so the time it would take to
recapture the cost difference would be longer.

Financial focus aside, how does the stretch-plastic
system function? Stretch plastic is "tacky"to the touch,
so overlapping layers form a seal against air leakage
as long as the plastic stays free of holes. Holes in the
plastic cover are caused by many things: A common
cause is the breaking down of the plastic due to ultra-
violet radiation from the sun. This type of failure often
covers large areas and cannot be patched. So, the
plastic used must have sufficient ultraviolet inhibitor
to avoid having this type of plastic failure. (Eventually
this type of failure should not occur because forage
producers will soon learn which plastic manufacturer's
products last throughout the storage period.)


Page 3







Equipment for Preserving Forage as Round-Bale Silage

Small holes have different sources: birds walking
on the bale, and pecking the bale. Another source is
worms boring holes in the plastic after adult insects
have laid eggs on the bale awaiting wrapping. Round-
bale silage producers can avoid this last problem by
wrapping bales as soon as possible. This also keeps the
bale from overheating.

Small holes can be patched with tape and will not
cause a major failure if detected early. One of the
major advantages of the stretch-plastic system is that
a "pin" hole in the plastic that goes undetected and
unpatched will not result in total bale spoilage. A
spoilage zone in the immediate area of the hole will
develop, but the complete bale will not spoil as
happens when the bale is stored in the loose-fitting
bags and tubes.

BALERS

Making round-bale silage is not yet a common
practice in the United States, but many ranchers and
dairyman have at least heard about it. Many of these
producers may never try to make round-bale silage,
but if they wanted to try it they would want a baler
that could bale wet forage. Baler manufacturers are
aware of this interest, and most of the balers on the
market today are designed to bale wet forage.

Probably the easiest way to determine whether a
baler works satisfactorily in wet forage is to request a
demonstration of the baler. The forage should be
baled at various moisture levels, ranging from the level
immediately after cutting to the level after
approximately 3 hours of wilting during good drying
conditions. This will probably correspond to an 85 to
50 percent range of moisture in many forages,
depending on maturity and the prevailing drying
conditions.

It is probably more important that the baler
perform satisfactorily when baling wilted forage
because the silage resulting from wilted forage is
usually more desirable.

Research conducted at the University of Florida
indicates that the best round-bale silage is produced
from forage that has been wilted to the 50 to 60
percent moisture level before it is baled. More of the
wilted silage was eaten by the cattle, and the cattle
were in better condition after wintering on wilted
forage than were a similar group of cattle fed silage
made from forage that was baled immediately after
mowing.


Page 4


Another benefit from wilting was that comparably
sized bales contained more dry matter than the wetter
bales. The higher level of dry matter is an economic
advantage because more dry matter can be preserved
with a given amount of plastic when the forage is
wilted.

The bale chamber of a round baler is either of the
variable or fixed-chamber design. The difference in
how these two baler designs form a bale is important
to forage producers considering making round-bale
silage. Wet bales weigh approximately twice the weight
of a hay bale of comparable size; thus, a large wet bale
could present a handling problem.

Variable-chamber balers produce a bale with
relatively uniform bale density because the bale is
subjected to a "squeezing" force while the bale is being
formed. A bale formed in a variable-chamber baler
can be ejected from the baler at any desired diameter
and the bale will be dense and relatively free of
oxygen within the forage mass.

This design feature of variable-chamber balers
enables a producer to make round silage bales in a
smaller diameter than the hay bales normally formed
by the baler. This reduces bale weight.

Fixed-chamber balers produce a bale that has a
variable density. The density is relatively low at the
center of the bale and gets progressively higher near
the bale's outer edge. The initial forage conveyed into
the bale chamber of a fixed chamber baler is not
"squeezed" until the baler takes in enough forage to
fill the bale chamber. The "squeezing" force results
from the baler taking in more forage into a space
already filled with fluffy forage.

In order to form a relatively dense bale, a fixed-
chamber baler must be carried close to full size. A
forage producer considering making both silage and
hay with a fixed-chamber baler might choose a baler
that makes a smaller diameter bale than would
normally be chosen for making hay alone, in order to
avoid handling extremely heavy wet bales.

STRETCH-PLASTIC WRAPPING MACHINES

Machines for wrapping wet bales with stretch
plastic have been used in the United States since the
mid-1980s. They were developed in northern Europe
where round-bale silage making with these machines
is reportedly a relatively common practice.







Equipment for Preserving Forage as Round-Bale Silage

Small holes have different sources: birds walking
on the bale, and pecking the bale. Another source is
worms boring holes in the plastic after adult insects
have laid eggs on the bale awaiting wrapping. Round-
bale silage producers can avoid this last problem by
wrapping bales as soon as possible. This also keeps the
bale from overheating.

Small holes can be patched with tape and will not
cause a major failure if detected early. One of the
major advantages of the stretch-plastic system is that
a "pin" hole in the plastic that goes undetected and
unpatched will not result in total bale spoilage. A
spoilage zone in the immediate area of the hole will
develop, but the complete bale will not spoil as
happens when the bale is stored in the loose-fitting
bags and tubes.

BALERS

Making round-bale silage is not yet a common
practice in the United States, but many ranchers and
dairyman have at least heard about it. Many of these
producers may never try to make round-bale silage,
but if they wanted to try it they would want a baler
that could bale wet forage. Baler manufacturers are
aware of this interest, and most of the balers on the
market today are designed to bale wet forage.

Probably the easiest way to determine whether a
baler works satisfactorily in wet forage is to request a
demonstration of the baler. The forage should be
baled at various moisture levels, ranging from the level
immediately after cutting to the level after
approximately 3 hours of wilting during good drying
conditions. This will probably correspond to an 85 to
50 percent range of moisture in many forages,
depending on maturity and the prevailing drying
conditions.

It is probably more important that the baler
perform satisfactorily when baling wilted forage
because the silage resulting from wilted forage is
usually more desirable.

Research conducted at the University of Florida
indicates that the best round-bale silage is produced
from forage that has been wilted to the 50 to 60
percent moisture level before it is baled. More of the
wilted silage was eaten by the cattle, and the cattle
were in better condition after wintering on wilted
forage than were a similar group of cattle fed silage
made from forage that was baled immediately after
mowing.


Page 4


Another benefit from wilting was that comparably
sized bales contained more dry matter than the wetter
bales. The higher level of dry matter is an economic
advantage because more dry matter can be preserved
with a given amount of plastic when the forage is
wilted.

The bale chamber of a round baler is either of the
variable or fixed-chamber design. The difference in
how these two baler designs form a bale is important
to forage producers considering making round-bale
silage. Wet bales weigh approximately twice the weight
of a hay bale of comparable size; thus, a large wet bale
could present a handling problem.

Variable-chamber balers produce a bale with
relatively uniform bale density because the bale is
subjected to a "squeezing" force while the bale is being
formed. A bale formed in a variable-chamber baler
can be ejected from the baler at any desired diameter
and the bale will be dense and relatively free of
oxygen within the forage mass.

This design feature of variable-chamber balers
enables a producer to make round silage bales in a
smaller diameter than the hay bales normally formed
by the baler. This reduces bale weight.

Fixed-chamber balers produce a bale that has a
variable density. The density is relatively low at the
center of the bale and gets progressively higher near
the bale's outer edge. The initial forage conveyed into
the bale chamber of a fixed chamber baler is not
"squeezed" until the baler takes in enough forage to
fill the bale chamber. The "squeezing" force results
from the baler taking in more forage into a space
already filled with fluffy forage.

In order to form a relatively dense bale, a fixed-
chamber baler must be carried close to full size. A
forage producer considering making both silage and
hay with a fixed-chamber baler might choose a baler
that makes a smaller diameter bale than would
normally be chosen for making hay alone, in order to
avoid handling extremely heavy wet bales.

STRETCH-PLASTIC WRAPPING MACHINES

Machines for wrapping wet bales with stretch
plastic have been used in the United States since the
mid-1980s. They were developed in northern Europe
where round-bale silage making with these machines
is reportedly a relatively common practice.






Equipment for Preserving Forage as Round-Bale Silage

Four types of the machines are available from a
number of different manufacturers. There are two
three-point, lift-mounted models (Figures 7 and 8),
and two models that are mounted on a trailer (Figures
9 and 10). The machine shown in Figure 7 elevates
the bale, wraps it, and gently lowers the bale onto the
ground.

The second three-point mounted unit (Figure 8)
is the least costly of the four wrappers. The bale has
to be placed onto this machine's wrapping platform by
a tractor equipped with a front-end loader.


Page 5


Figure 9. Trailer-mounted bale wrapping machine without
integral bale-loading device.


Figure 7. Three-point lift-mounted balewrapping machine sets
wrapped bale on the ground.


Figure 8. Three-point lift-mounted
dumps bale using hydraulic ram.


bale-wrapping machine


The two trailer-mounted machines and the less
expensive three-point, lift-mounted unit (Figures 8, 9,
and 10) are similar in design. The trailer-mounted
machine in Figure 9 requires a front-end-loader-
equipped tractor to load the bale onto the wrapping
platform; the one in Figure 10 has a hydraulically
powered lift as an integral part of the machine to
place the bale onto the wrapping platform.


Figure 10. Trailer-mounted bale-wrapping machine with
integral bale-loading device.

The two wrapping machines that have their own
integral bale lifting device (Figures 7 and 10) are the
most expensive wrapping machines, costing about
$14000 each. The wrapping machines are powered by
a connection to the hydraulic system of a tractor or by
a small gasoline engine. Most models use tractor
hydraulic power.

The wrapper in Figure 7 turns the bale slowly on
its horizontal axis by rotating the lift arms used to
elevate the bale. The plastic wrap is mounted on an
arm that rotates about a vertical axis. The end of the
plastic is secured under the twine of the bale, and the
rotation of the plastic roll on the vertical axis causes
the plastic to be stripped from the roll and wrapped
around the bale.

The slow rotation of the bale is what makes the
plastic wrap cover the complete bale with the plastic.






Equipment for Preserving Forage as Round-Bale Silage

If the bale did not rotate on its horizontal axis, the
plastic would be applied as a single 20-inch-wide band
about the bale. The local band would thicken with
each revolution of the plastic around the bale, but the
bale would not be completely covered.

The relative rotational speed of the arm carrying
the plastic and the bale itself is what determines the
amount of overlap between layers of plastic. The
overlap is usually about 50 percent of the plastic
width. In other words, each layer is shifted 10 inches
over from the previous layer when 20-inch-wide plastic
is used.

All of the other wrappers (those in Figures 8
through 10) have the roll of plastic mounted on a
pedestal attached to the stationary frame of the
wrapping machine. The end of the plastic is secured
under the bale twine, but the plastic is stripped from
the plastic roll by the bale rotating about a vertical
axis. The bale is also slowly turned on its horizontal
axis in order to cover the bale as just described.

After wrapping the bale with 4 to 6 layers of the
plastic, the machine in Figure 7 cuts the plastic and
gently lowers the bale to the ground. On the other
machines the wrapping platform (or cradle) that the
bale sits in during the wrapping operation is tilted by
a hydraulic ram to drop the bale onto the ground or
onto a special mat designed to reduce the chances of
puncturing holes in the plastic when the bale is
dropped on grass stubble. The mats also appear to
reduce the stretching of the plastic wrap caused by the
shock loading that the bale endures when it is dropped
on the hard ground.

Descriptions aside, the best way to get an idea of
how the machines work is to watch a videotape
"Plastic Wrapped Round Bale Silage: An Alternative
System." This tape is available at the Cooperative
Extension Office in all Florida counties.

SILAGE BALE HANDLING EQUIPMENT

After the bales have been wrapped with the
stretch plastic and placed on the ground, they are
usually stored until they are fed to cattle. Bales can be
moved with a front-end loader-mounted spear as hay
bales are moved, but the hole made in the plastic by
the spear must be patched with a special type of tape
that sticks to the plastic wrap. Silage bales made
during the first few years of the roll-bale silage
research project conducted at the University of


Page 6


Florida's Pine Acres Research Farm were moved using
such a spear.

This method was abandoned because the tape used
to patch the hole caused by the spear came loose
causing considerable spoilage. The bales were then
handled using special equipment mounted on a front-
end loader that squeezed the bale tightly and was able
to move the bale without piercing the plastic cover
(Figures 11 and 12). This specialty equipment again
adds to the cost of producing bale silage, but it is felt
that it is worth the added investment in order to
improve silage quality.


Figure 11. Bale handler used to move plastic-wrapped bales.
Figure 11. Bale handler used to move plastic-wrapped bales.


Figure 12. Bale handler used to move plastic-wrapped bales.

CONCLUSIONS

Producing round-bale silage using stretch plastic,
and a special machine for wrapping bales with that
plastic, is a relatively low-cost method. The forage
producer equipped with only one additional piece of
equipment, the wrapping machine, is able to harvest
forage at its nutritional peak (4 to 6 weeks of






Equipment for Preserving Forage as Round-Bale Silage

If the bale did not rotate on its horizontal axis, the
plastic would be applied as a single 20-inch-wide band
about the bale. The local band would thicken with
each revolution of the plastic around the bale, but the
bale would not be completely covered.

The relative rotational speed of the arm carrying
the plastic and the bale itself is what determines the
amount of overlap between layers of plastic. The
overlap is usually about 50 percent of the plastic
width. In other words, each layer is shifted 10 inches
over from the previous layer when 20-inch-wide plastic
is used.

All of the other wrappers (those in Figures 8
through 10) have the roll of plastic mounted on a
pedestal attached to the stationary frame of the
wrapping machine. The end of the plastic is secured
under the bale twine, but the plastic is stripped from
the plastic roll by the bale rotating about a vertical
axis. The bale is also slowly turned on its horizontal
axis in order to cover the bale as just described.

After wrapping the bale with 4 to 6 layers of the
plastic, the machine in Figure 7 cuts the plastic and
gently lowers the bale to the ground. On the other
machines the wrapping platform (or cradle) that the
bale sits in during the wrapping operation is tilted by
a hydraulic ram to drop the bale onto the ground or
onto a special mat designed to reduce the chances of
puncturing holes in the plastic when the bale is
dropped on grass stubble. The mats also appear to
reduce the stretching of the plastic wrap caused by the
shock loading that the bale endures when it is dropped
on the hard ground.

Descriptions aside, the best way to get an idea of
how the machines work is to watch a videotape
"Plastic Wrapped Round Bale Silage: An Alternative
System." This tape is available at the Cooperative
Extension Office in all Florida counties.

SILAGE BALE HANDLING EQUIPMENT

After the bales have been wrapped with the
stretch plastic and placed on the ground, they are
usually stored until they are fed to cattle. Bales can be
moved with a front-end loader-mounted spear as hay
bales are moved, but the hole made in the plastic by
the spear must be patched with a special type of tape
that sticks to the plastic wrap. Silage bales made
during the first few years of the roll-bale silage
research project conducted at the University of


Page 6


Florida's Pine Acres Research Farm were moved using
such a spear.

This method was abandoned because the tape used
to patch the hole caused by the spear came loose
causing considerable spoilage. The bales were then
handled using special equipment mounted on a front-
end loader that squeezed the bale tightly and was able
to move the bale without piercing the plastic cover
(Figures 11 and 12). This specialty equipment again
adds to the cost of producing bale silage, but it is felt
that it is worth the added investment in order to
improve silage quality.


Figure 11. Bale handler used to move plastic-wrapped bales.
Figure 11. Bale handler used to move plastic-wrapped bales.


Figure 12. Bale handler used to move plastic-wrapped bales.

CONCLUSIONS

Producing round-bale silage using stretch plastic,
and a special machine for wrapping bales with that
plastic, is a relatively low-cost method. The forage
producer equipped with only one additional piece of
equipment, the wrapping machine, is able to harvest
forage at its nutritional peak (4 to 6 weeks of






Equipment for Preserving Forage as Round-Bale Silage

regrowth for many forages produced in Florida)
because this system makes silage even when hay
cannot be made under prevailing weather conditions.

Without the flexibility offered by the silage-making
option, the forage must be harvested when the
weather appears to offer a 2- to 3-day period of
reasonably good drying conditions. Forage will often
have to remain in the field until it is overly mature
and of poor quality during the peak growth months of
the summer in Florida and many other areas of the
southeast. Sometimes the forage is of such poor
quality when harvested that the primary reason for
harvesting it is to get it out of the way so that some
new high-quality forage can grow in its place.

Fortunately, poor-quality forage harvested as hay
is not a total loss because roughage is needed in cattle
diets. But delays caused by waiting on hay harvesting
weather often reduces the number of harvests and the
tonnage produced during the growing season.

The ability to harvest a forage as silage might
make growing high-quality legume forages such as
alfalfa and perennial peanut profitable for producers
who have difficulty getting all of their harvests put up
as hay. Alfalfa should be harvested when about 10
percent of the plants are in bloom (about 30 days of
regrowth). The interval between when alfalfa should
be harvested and when it sheds its leaves and is
nothing but stems is relatively short, so a producer of
alfalfa should plan to harvest part of his crop as silage
or by grazing.

The timely harvest of perennial peanut is not as
critical as it is for alfalfa because disease does not
cause the leaves to drop from the peanut plant as
soon as it does in alfalfa. However, a delay in
harvesting the peanut plant to be stored as hay means
the amount of forage to be dried to a safe storage
moisture level (15 to 20 percent) will be greater, and
the time the crop must lie in the field and be
subjected to possible rain showers will be longer.


Page 7


The chances of satisfactorily harvesting perennial
peanut as hay may be greater than that of alfalfa, but
the chance of successfully storing either of these
quality legumes would be increased with the ability to
make silage when the weather indicates little chance
of long-term drying in the field.

As mentioned earlier, machines for applying
stretch-wrap plastic to wet, round bales for making
silage were developed in northern Europe. The
potential for making good silage using a plastic
wrapper to exclude oxygen from the bale is probably
better in northern Europe than it is in the
southeastern United States as the plastic is less apt to
break down due to the sun's ultraviolet rays there.

In order to make quality silage it is absolutely
essential that plastic remain intact. The plastic used
for making round-bale silage in the southeastern
United States must have sufficient ultraviolet light
inhibitors mixed into the plastic resin so it can last for
6 to 8 months of outside storage. There are some
plastics that can stand up under the intense sun of the
southeast, but there are some that cannot. Fortunately,
many manufacturers of plastics that had insufficient
UV inhibitors in their stretch-wrap plastic have already
withdrawn their products from the market.




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs