Everglades Station Mimeo Report 62-26
Grazing Trial Results for One Year (1960-1961)
C. E. Haines and R. J. Allen, Jr.1
Determining the productivity of pasture forages, via grazing animals has
been used for many years by numerous investigators all over the world. However,
studies on forages must be continued so that systems may be developed to increase
the productivity of various forages. Ahlgren (1) estimates that the Southeastern
part of the United States could increase its livestock production by 475% through
the application of results of research and expanding research in forages. Forage
crops are extremely important to cattle producers on the organic soils of South
Florida where year around grazing is practiced.
A summary of five years work by Kidder et al (2), on organic soils, showed
that 1,004 Ibs. of weight gain per year was obtained from an acre of Roselawn
St. Augustinegrass and 920 Ibs. from paragrass and caribgrass pastures. Year-
ling cattle were used in the studies. A similar study by Haines and Chapman (3),
at the same location, did not include caribgrass but contained information on
pangolagrass and bahiagrass. Annual total gains in weight per acre were 1075
1070, 1055 and 860 Ibs. for bahiagrass, paragrass, Roselawn St. Augustinegrass
and pangolagrass, respectively. Last year, Haines and Allen (4) reported lower
annual gains from these same grasses and a variation in order of productivity.
Total gains per acre for the year were 915, 795, 625 and 600 pounds for Roselawn
St. Augustinegrass, paragrass, pangolagrass and bahiagrass, respectively.
This latter study was continued and the data reported herein was secured
during the following year. However, the pangolagrass plots were eliminated
from the trial on the basis of previous production and management problems.
Twelve lots, each two acres in size, were randomly located within a forty
acre field. Four of the lots were established in Roselawn St. Augustinegrass,
four in paragrass, two in Argentine bahiagrass and two in Pensacola bahiagrass.
Pastures were fertilized in the fall with mixtures based on annual soil analysis.
Yearling steer calves, of various breeding, were used to continuously graze the
blocks for a one year period. The animals were assigned to the test blocks on
the basis of initial weight and breeding and averaged approximately 425 pounds
at the beginning of the trial. The trial began on November 3, 1960 and ter-
minated on November 2, 1961.
A minimum stocking rate of two yearlings per acre was maintained throughout
the entire year on each test block. When forage production exceeded that con-
sumed by the "base" animals, other yearlings called "grazers" we the
particular block or blocks. These "grazers" were added or ren pa t
weigh dates which occurred every two weeks. The "grazers" we ept in a
group" when not grazing the extra forage in the test blocks. ',t
1 Assistant Animal Husbandman and Assistant Agronomist respectively, Everglades
Experiment Station, Belle Glade, Florida.
During the winter period, the base animals in one half of the blocks of
each grass were supplied chopped sugarcane as a pasture supplement. An average
of 20 pounds of sugarcane per head daily was provided for a 12 week period when
forage production was at a low level. The yearlings in the other half of the
test blocks (6 blocks) were given no additional supplemental feed during the
year. Each block contained an automatic water cup and mineral feeder. The
mineral consumption was recorded for each block.
Animals were individually weighed at 14 day intervals throughout the year
and their gains converted to total pounds of gain per acre of grass.
Providing chopped sugarcane during the winter was beneficial only to the
yearlings on paragrass pastures. The steers receiving the sugarcane on paragrass
pastures gained an average of approximately 19 pounds during the 12 week period
compared to an average loss of 21 pounds by steers not getting sugarcane. This
difference of about 40 pounds in favor of the sugarcane supplementation was
statistically significant. During this same period, the average gains of steers
with and without sugarcane on St. Augustinegrass pastures differed by 7 pounds
in favor of no supplementation. Steers, on both kinds of bahiagrass combined,
gained an average of 45 pounds when supplied sugarcane and 44 pounds without the
sugarcane supplementation. A summary of the responses to sugarcane supplement-
ation is shown in Table 1.
Table 1. Average Weight Changes of Yearlings in a 12 Week Period on Two Levels
of Sugarcane Supplementation (ibs.)
Kind of grass No sugarcane Chopped sugarcane from sugarcane
St. Augustine 83 76 7
Para -21 19 +40
Argentine Bahia 63 43 -20
Pensacola Bahia 25 48 +23
The supplementation of pastures with sugarcane failed to affect the total
annual productivity of the various grasses. Blocks that were not supplemented
produced just as much pounds of gain over the year, as those that were supple-
mented with sugarcane. The average body weights of the base animals on paragrass,
with and without sugarcane, were compared at the two-week weigh periods through-
out the year since animal gains during the winter period were significantly
affected by sugarcane supplementation. Although there was a response to sugar-
cane during the winter, this advantage diminished to some extent in the grazing
period following the supplementation period. Initially, the base animals on
paragrass that received sugarcane weighed an average of 7 pounds more than the
non-supplemented animals. This difference increased to 34 pounds by the end
of the sugarcane feeding period but then dropped to only a 25 pounds advantage
eight months later (termination of trial).
The actual pounds of live animal gains and carrying capacities per acre are
important measurements of forage productivity. These values from the various
test blocks were combined to obtain data for the different grasses involved.
Data were also combined for the two sugarcane treatments, within the respective
grass groups, since the sugarcane did not influence overall annual productivity.
A summary of the annual productivity per acre of each grass, is shown in the
Table 2. Average Weight Gains and Carrying Capacities Per Acre for One Year.
Kind of grass Grazing days Weight gains (lbs.) Daily gains (Ibs.)
St. Augustine 1,008 1,100 1.09
Para 945 970 1.02
Argentine Bahia 1,092 880 0.81
Pensacola Bahia 966 705 0.73
As expected, there was a great variation in total gains produced per acre
in different times of the year for all of the grasses. The poorest gains were
recorded in a twelve week period beginning on December slt and ending on
February 23rd. During this quarter of the year, the percentages of the annual
gains per acre from animals grazing St. Augustinegrass, paragrass, Argentine
Bahiagrass and Pensacola Bahiagrass were 6.8%, 1.7%, 4.1% and 4.3%, respectively.
Thus, St. Augustinegrass showed a higher rate of productivity in these twelve
weeks than did the other grasses. Since twelve weeks is approximately 25% of
the year, if annual productivity had been uniform throughout the year the per-
centage of total gains occurring during this period should have approached 25%.
Large gains per acre occurred in the twelve week period from May 4th
through July 27th. Slightly over one half or 52.7%, of the total annual gains
from paragrass were produced during this period. For St. Augustinegrass 37.8%,
or over one third of the annual gains, occurred in this period. The percentage
of annual gains during this same period, or quarter, from Argentine Bahiagrass
and Pensacola Bahiagrass were 40.6% and 33.6% respectively.
To illustrate the fluctuation in weight gains of the steers on the various
grasses the weight changes were plotted. These data are presented in figures 1
and 2. For these figures, the total gains recorded at a weight period were
adjusted by using data from adjacent periods and calculating "running averages".
The "running average" used for a particular weigh date was obtained by combining
the gains for this period with those of the previous and following weigh periods.
The average of these three values was used as the adjusted value or "running
average" for the middle weigh period. Although this procedure tends to minimize
the peaks of such constructed curves, the values indicated are considered more
realistic for productivity trends as related to seasonal fluctuations.
Figure 1 illustrates that paragrass has a shorter period of high producti-
vity, during the year, than St. Augustinegrass. However, during its short period
of maximum productivity, it was superior to St. Augustinegrass. The St. August-
inegrass was at a high rate of productivity over a longer period of the year than
paragrass. In figure 2, the duration of high productivity are similar for the
two kinds of Bahiagrass but the peaks are lower than those for the other two
grasses. This relationship is proven by the total annual gains previously
presented in table 2.
The average daily salt-trace mineral mixture consumption for all animals
for the entire year (23,856 animal grazing days) was 0.13 pounds. On a monthly
basis, the greatest intake of minerals per steer occurred in July and the
smallest in December and January. Although differences in mineral consumption
due to the kind of grass grazed were not large, animals on St. Augustinegrass
showed the highest rate of mineral consumption and those on paragrass.the
The productivity of Roselawn St. Augustinegrass, paragrass, Argentine
Bahiagrass and Pensacola Bahiagrass was compared by using yearling steers as
grazing animals in blocks of each kind of grass. During the winter, one half
of the steers on each kind of grass were provided chopped sugarcane. A minimum
stocking rate of two yearlings per acre was practiced, with additional yearlings
used during periods of excessive forage production. Animals were individually
weighed at 2-week intervals throughout a year period and live weight changes
used to determine the productivity of the forages.
The yearlings grazing paragrass were the only ones to show a response to
sugarcane supplementation during the winter. However, at the end of the study
this advantage had diminished considerably. The annual productivity of each
of the grasses was not affected by the use of the sugarcane during the 12 weeks
The total animal gains per acre for St. Augustinegrass, paragrass, Argentine
Bahiagrass and Pensacola Bahiagrass were 1100, 970, 880 and 705 pounds, res-
pectively. The annual number of grazing days, per acre, were 1008, 945, 1092
and 966 for these grasses in the same order. More than 50% of the annual gains
from paragrass were obtained during a 12 weeks period between May 4th and July
27th and less than 2% for the 12 weeks between December 1st and February 23rd.
The gains for the period between May 4th and July 27th from the other three
grasses ranged between 30 and 40 percent of their annual productivity. The
duration of high productivity was the longest for St. Augustinegrass and the
shortest for paragrass.
1. Ahlgren, Henry L. 1962. Livestock Breeder Journal. 5:2. p. 96.
2. Kidder, R. W., R. J. Allen, Jr., H. L. Chapman, Jr. and D. W. Beardsley.
1957. Yield of Everglades Pasture as Measured by Growth of Yearling
Cattle. Jour. An. Sci. 16:1058.
3. Haines, C. E. and H. L. Chapman, Jr. 1960. Results of Grazing Experiments
With Yearling Calves on Four Major Pasture Grasses of the Everglades for
One Year. E.E.S. Mimeo Rpt. 60-16.
4. Haines, C. E. and R. J. Allen, Jr. 1961. Grazing Trial Results for One
Year (1959-1960). E.E.S. Mimeo Rpt. 61-11.
EES Mimeo Rpt. 62-26
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