/ 6 )
SILAGE AS A FEED FOR
FATTENI M CATTLE
Herbert L. Chapman, Jr.
This report is made up from information ob-
tained from research and extension personnel
throughout the state of Florida and experi-
ments repeated elsewhere in the County. It
is presented as part of the program included
in the Beef Cattle Breeders' and Herdsmen's
Short Course held at the University of Florida
in Gainesville on April 12, 13 and 1l, 1956.
EVERGLADES STATION MIMEO REPORT 56-9
Belle Glade, Florida
April 10, 1956
JP1A P- 144 If Lt M ->'lp PIP-."^-'-^?
Silage as a Feed for Fattening Cattle
Herbert L. Chapman, Jr.
Assistant Animal Nutritionist
Two factors which are of major importance in determining the profit a
cattle feeder may or may not make are (1) the rate of gain of the cattle being
fed and (2) the amount and cost of feed required to produce a pound of gain. The
present day feeder must contend with the problem of producing the optimum rate of
gain which is most economically feasible. The maximum rate of gain will not neces-
sarily be the most profitable one. This is particularly true in Florida where the
larger percentage of cattle in the State do not possess the inherent ability to util-
ize efficiently a full feed of concentrates. On the other hand, the cattlemen who do
possess top quality feeders are also looking for ways to furnish their cattle a well-
balanced ration at a more economical cost. These factors have resulted in an in-
crease in the amount of roughage fed to fattening beef cattle, with the two major
possibilities for providing a year-around supply of roughage being either hay or
Dry roughage, or hay, has been used extensively, However, nutrients can be
better preserved in silage than in dry roughages. Nutritive value of silage is
greater than in an equal volume of hay and silage making has certain advantages in
the Southeastern States as compared to hay. Since it is not essential to the proper
nutrition of beef cattle that a dry roughage be supplied, provided the ration is pro-
perly balanced by other feeds, there has been an increased interest in the use of
silage for the fattening of cattle.
Much has been said concerning the value of the various silages as a means of
extending feed supplies for wintering cattle. A recent survey of the County Agents
in Florida indicated that many cattlemen in the State are utilizing silage for this
purpose. However, there is an interest as to how this roughage might be utilized for
fattening cattle-as evidenced by the report (Figure 1) that 55 cattlemen in the
state are using it to some degree in their fattening program. Of these 19 were em-
ploying corn silage and 36 grass, or grass-legume, silage. There was great diversi-
fication regarding the kind of supplemental ration used, ranging from the use of com-
plex cattle feed supplements to straight corn or protein meal.
Kinds of Silage
Cattle feeders have been using corn silage extensively for approximately h4
years. While the nutritional value of this silage varies according to stage of ma-
turity of the corn when cut, yield of corn per acre and method of ensiling, it is gen
erally quite palatable and high in nutrient quality. Many early experiments have
shown corn silage to produce more economical gains than corn grain and hay. It has
been demonstrated at the Ohio Station that more steer days of feed per acre and gain
per acre were obtained when corn silage was fed as compared to harvesting and feeding
corn stover and grain separately. Subsequent reports from the same station indicated
more beef was produced per acre from silage alone as compared with one-half as much
silage plus a full feed of corn. However, the gains on the steers receiving silage
alone were slower and the carcasses did not grade as high.
Talk presented to Beef Cattle Breeders' and Herdsmen's Short Course, University of
Florida, April 13, 1956.
Figure 1. Number of Cattlemen in Florida Using Silage to Fatten Beef Cattle.*
-., GRASS 5
Y x... / V
~ CORN 7
Corn Silage 19 CORN 2
Grass Silage 36RASS 9
As indicated by a 1956 survey of County Agents.
Information was not available from Alachua, Brevard,
Dade, Escambia, Gilchrist, Hendry, Jefferson, Nassau,
Santa Rosa and Seminole Counties.
While corn silage yield varies greatly, a 50 bushel crop will reportedly pro-
duce between 8-10 tons of silage per acre depending upon the quantity of leafy ma-
terial and the size of the corn stalk. In a recent study at the Everglades Station
75 bushel corn produced 19 tons of corn silage having 28 per cent of dry matter per
acre. The chemical composition of corn silage will vary according to the ratio of
grain and plant material in the silage. On the average, however, good quality corn
silage, harvested when the kernel is in the dent or glaze stage, is high in energy
content, vitamins A and D, contains approximately 20 per cent total digestible nutri-
ents and is somewhat low in mineral and protein content.
The cattleman is interested in producing the most economical gains. This has
led to extensive research during the past years to determine what type of supplement
is needed to best complement the nutritive inadequacies of corn silage. Workers at
the Purdue and Iowa Experiment Stations have offered rather complex feed supplements
such as Purdue Supplement A and B, and Iowa Supplement 1, 3 and 3a which are usually
fed at a rate of approximately 3.5 pounds per animal per day, along with a full feed
of silage. This type of ration has been demonstrated to produce quite satisfactory
More recent work at the Oklahoma and North Dakota stations indicate that a
simple protein supplement along with minerals will produce as satisfactory a rate of
gain as the more complex supplement, at a more economical cost. This would appear
very reasonable since the principle nutritional shortcomings of good quality corn
silage are inadequate protein and minerals.
It has also been conclusively demonstrated that if it is desired to obtain
the finish to qualify for the higher market grades sufficient grain must be available
to the cattle. High roughage rations will not produce as high a rate of gain or as
quick a finish as will high-concentrate rations, due to a lower daily intake of total
digestible nutrients. Longer feeding periods are needed when high roughage rations
are used. If steers are fed poor or average quality corn silage, extra corn in addi-
tion to the protein and mineral supplements, must be supplied during the last 50 or
60 days of the feeding period in order to place the desired finish on the individual
This term here-in is loosely used to include silages made of grasses, legume:
or grass-legume mixtures. Grass silage is not a new product but was first used ex-
tensively during the middle 1930's. Good quality grass silage provides a means of
preserving extra forage so that more nutrients are preserved than by any other man-
ner. While it is used extensively in Central and Southern Florida for wintering beef
cattle it offers potential possibilities as a feed for fattening beef cattle, if pro-
perly supplemented with the necessary nutrients to provide the finish desired in the
There have been conflicting results both experimentally and in the feed lot
concerning the value of grass silage for fattening cattle. Reasons for these vari-
ances apparently include differences in the kind of plant used, the stage of maturity
of the plants used and the method by which the silage was preserved. Sufficient ex-
perimentation has been done with grass silage to allow the drawing of certain con-
clusions regarding its value for fattening cattle and to allow suggestions for how it
should be used in a cattle fattening program.
The proximate analysis of grass silage used at the Everglades Experiment
Station is given in Table One. In order to produce good quality grass silage the
forage should be cut in the pre-full bloom stage and a preservative used. Good qual-
ity grass silage is high in carotene (a source of Vitamin A), contains more mineral
and protein but less energy than good quality corn silage and will have approximately
18 per cent of total digestible nutrients. A cubic foot of silage weighs approxi-
mately 60 pounds or 8-9 tines as much as a cubic foot of loose hay and contains about
3 times as much food value. There is a great deal of variance in the quality of
grass silage, however, and poor quality grass silage may be low in carotene, high in
moisture, possess undesirable odors and contain only 10-12 per cent of total digest-
ible nutrients. These factors are at least partially responsible for the variance in
results obtained from feeding grass silage.
Table 1. Chemical Analyses of Crass Silages used at the Everglades Experiment
Kind of Dry Protein Ether Fiber Ash N.F.E.
Grass Matter Extract
% (per cent, dry matter basis)
St. Augustine 25 11.6 3.5 32.5 7.6 44.8
Para 20 8.3 2.0 40.1 10.7 38.1
Carib 18 12.2 3.4 32.6 9.0 42.8
Pangola 25 13.2 14l 34.2 7.2 41.3
Experiments conducted at Purdue have demonstrated that cattle full fed good
quality grass silage plus 7 pounds of ground corn made as good a rate of gain as did
cattle full fed good quality corn silage plus 3.5 pounds daily of Purdue Supplement A
at a more economical cost. Earlier work at Michigan State also demonstrated that
similar rates of gain were obtained when steers were fed corn silage or grass silage
which was supplemented with an energy containing feed. The relative nutritive values
of corn and grass silage is shown in Table Two.
Table 2. Relative Nutritive Values of Good Quality Corn and Grass Silage.
Nutrient Silage Silage
Protein High Low
Energy Low High
Minerals High Low
Vitamins High High
In a recent experiment at the Everglades station medium grade feeder steers
reached the commercial slaughter grade when full-fed grass silage for 120 days plus
six pounds of a concentrate mixture daily which consisted of equal parts of ground
snapped corn, citrus pulp and cane molasses. Feed supplements to be used with grass
silage do not need to have excessive protein. The major shortcomings of good quality
grass silage, from the nutritional point of view, is that it lacks the energy to put
fast gains and finish on cattle. While it is not necessary to supplement good qual-
ity grass silage with protein meals it is necessary to supply extra energy in the
form of grain such as corn in order to obtain maximum rate of gain and finish from
the cattle. Grass silage and ground corn will apparently produce an adequate and
more economical rate of gain than when the silage is fed with a complex feed supple-
Early work at the Florida Experiment Station demonstrated that comparable rates
of gain were obtained when steers were fed fattening rations containing Sorghum
Silage or Peanut Hay. Work at other stations have further demonstrated that sorghum
silage can be well utilized by beef cattle,
Sorghum silage is similar to corn silage in composition except that it is some
lower in protein content, will have less total digestable nutrients than well eared
corn silage and less vitamin A than good quality corn silage. While there is danger
of prussic acid poisoning when young sorghum plants are eaten by cattle, the danger
apparently is not present in sorghum silage.
Recent work at the Oklahoma Station has failed to show the need of a complex
supplement when sorghum silage comprises the major portion of a fattening ration for
steers. The complex supplements failed to appreciably improve the rate of gain ob-
tained from a simple protein meal supplementation.
Why Do Cattle need energy feed Supplements
when being fattened on Grass Silage?
Cattle require a minimum amount of total digestible nutrients (T.D.N.) to main-
tain themselves. The amount required for this maintenance is affected by the size
and age of the animal as well as other factors. In order for cattle to gain they
must first meet their maintenance requirements, after which additional T.D.N. may be
converted into body weight gains.
For example, an eight hundred pound 2 year old steer requires approximately $.7
pounds of T.D.N. daily, merely to maintain its normal body functions. Approximately
3.5 pounds more of T.D.N. is required for each pound of gain per day this steer makes,
This means that in order for the steer to gain two pounds a day, approximately 12.7
pounds of T.D.N. must be eaten, daily. If good quality grass silage were available,
containing 18 per cent of T.D.N., the steer would have to consume 70 pounds of silage
a day to satisfy this amount of T.D.N. If poorer quality grass silage is fed, con-
taining around 12 per cent T.D.N., approximately 100 pounds would be needed.
It is doubtful that a two year old steer will consume more than 45-5O pounds
daily of grass silage. This points out the necessity of supplying an amount of sup-
plemental T.D.N. in order to obtain the rate of gain desired. Since good grass si-
lage is adequate in protein it appears that ground corn is satisfactory to supply the
additional T.D.N. required.
1. For most economical gains in fattening beef cattle with silage:
(a) Supplement good quality corn silage with a protein meal such as a cotton-
seed or soybean oil meal.
(b) Supplement good quality grass silage with ground corn or similar energy
2. When good quality silages are used complex feeding supplements apparently do not
improve rate of gain above that obtained by these simple supplements sufficient-
ly to offset increased costs.
3. When poor quality corn or grass silage is used additional concentrate feeds will
be needed if rates of gains similar to that possible with good silages are to be
4, Use more silage when fattening lower quality of cattle.
5. Longer feeding periods (approx. 180-200 days) may be required where high rough-
age rations are used as compared to high grain rations. High roughage rations
do not yield as high a rate gain or as quick a finish because the animals cannot
consume the necessary nutrients needed. This is particularly true if low quali-
ty silages are used.
6. The feasibility of using large amounts of silage in fattening beef cattle is de-
pendent upon the development of low-cost harvesting, storage and feeding facili-
ties, the relative cost of grain and roughage, the quality of cattle being fat-
tened, the margin available to the feeder and the time the feeder desires to
market the cattle.