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not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
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Variety Grazing Trials
A grazing trial including six grasses and two annual legumes was begun
in 19b5 and continued for five years. Varieties included:
5. Argentine bahiagrass
6. Paraquay22 bahiagrass
7. Pensacola + Hairy indigo (late)
8. Pensacola + Aeschynomene
S. humilis (Townsville stylo) was seeded into Pensacola bahiagrass but the legume
made little growth and no grazing was obtained. The grass pastures were fertilize(
in spring and in fall, each time with 420 pounds per acre of 12-6-6 fertilizer.
The annual legumes were fertilized in spring with 250 pounds per acre of 0-8-24
with boron added. Each pasture trial unit included either 5 or 10 acres. In
case of the legume combination, one-half was legume-grass and one-half was pure
grass. The digitgrasses and stargrass units were divided into four parts and
used in rotation, one week of grazing and three weeks of regrowth. Bahiagrasses
were divided in halves and grazed one week and rested one week. The legumes
were allowed to grow in midsummer and then used in rotation with the grass part
cf the pasture unit.
Agricultural Research Center, Ona =lUME LIBRARY -*
Research Report RC-iq'6-4 Ma 1976
JUL 0 I1l8
.F.A.S.- Univ. of Florida
GRAZING RESEARCH AT ARC, ONA 19o5-1975
Elver M. Hodges (Agronomist), F. M. Peacock (Associate Animal
Husbandman) and H. L. Chapman, Jr. (Animal Nutritionist)
Grazing trials have been conducted at this location since 1942, beginning
with two groups of steers on fertilized carpetgrass, one pasture receiving a
mixture of minor elements and the other, none. Incidentally, that trial showed
a strong response to minor element fertilization.
Work done in the last ten years has had two parts: 1. Comparison of
different species with regard to adaptation, animal performance, and per acre
production; 2. Evaluation of various forage varieties and management systems
for cow-calf herds.
Weaned steer calves, "tester", were placed on the pastures (usually in
October) at one head per acre and stayed until the following October. They
received a concentrate supplement during late winter and spring when pastures
were depleted. Daily gain was calculated for two periods of the year:
"Winter" included the time from fall entry date to spring, (Usually March or
April) when feed supplement was no longer required. "Summer" gain was
calculated from the end of supplementation until cattle were removed.
Additional cattle were put on the pastures in spring and summer to utilize
available grass. These grazerr" cattle were not used to calculate daily gains
but were figured to make the same daily gains as the long-term steers. Daily
gain results are shown in Table I.1- No significant difference between
pastures was seen in winter daily gain. Summer daily gains were highest on the
digit and stargrasses and on Pensacola-Aeschynomene. The relatively high daily
gain on the grass-Aeschynomene pasture (a two year average) indicated the
possible value of that combination.
Table 1. Adjusted average daily gain per steer on grass and grass-legume
pastures, 1965-1970, Ona ARC.
Pasture Average Daily Gain, Ibs.
Winter Summer Yearl
Pangola 0.64 0.79ab* 0.75a*
Slenderstem 0.55 0.77abc 0.64ab
McCaleb 0.55 0.90a 0.73a
Pensacola 0.53 0.57bc 0.60bc
Paraguay 22 0.46 0.60bc 0.55bc
Argentine 1/ 0.40 0.55a 0.49c
Pensacola + HI- 0.53 0.60bc 0.57c
Pensacola + Aesch- 0.46 0.99a 0.75a
* Means within a column followed by different letters are significantly
different at the 5% level.
1/ three years
2/ two years
Supplement fed, grazing days per acre, gain per acre and final slaughter
grade (estimated)are shown in Table 2. It was apparent that the most feed
supplement was required on the bahiagrass. Low supplement use on the grass-
legume pastures was partially due to effect of the legume on spring grazing
1/ Hodges, E. M., F. M. Peacock, H. L. Chapman, Jr. and F. G. Martin. Grazing
trials with tropical grasses and legumes in peninsular Florida. 1976.
Proc. Soil and Crop Sci. Soc. Fla. in press.
Table 2. Yearly feed supplement, total grazing
and average final slaughter grade of
days per year, beef production per acre,
cattle on grass and grass-legume pastures,
Yearly feed Total Beef Adjusted
Pasture supplement grazing days production slaughter grade
Ibs./head per A lbs./A
Pangola 220 440 321 6.63/
Slenderstem 245 394 264 6.0
McCaleb 333 395 290 6.5
Pensacola 492 474 226 5.7
Paraguay 22 481 480 239 5.6
Argentine 520 458 193 5.1
Pensacola + HI1 139 355 186 6.1
Pensacola + Aesch2/ 64 386 259 5.5
1/ three years data
2/ two years data
3/ Estimated slaughter grade: 5-high utility; 6-low standard; 7-standard.
but also was affected by the shorter trial period which missed unfavorable
years. The graeing-days-per-acre record shows a similarity of stocking rate
among the different pasture types.
Beef production per acre for the year was highest on Pangola and lowest
on Argentine and the Pensacola-Hairy indigo. These figures showed the
desirability of Pangola, where a stand could be maintained. The relationship
between Pensacola and Paraguay 22 beef gains were variable, from year to year
and similar overall. Argentine consistently had the lowest yield of the
bahias, primarily because cold weather affected it more severely at Ona.
Slaughter grade data, estimated on live animals when removed from the trial
pasture in October of each year, showed no significant difference between
Pensacola Bahiagrass and Annual Legumes
Another grazing trial, was established to compare all-grass pastures with
others in which annual warm season legume'was grown.
This comparison covered the years 1971-1972-1973. Three groups of calves
were placed on the all-grass and three on the grass legume combination each
fall. Fertilization and management were similar to those described for the
earlier experiment except that grass fertilizer rate was increased from twice
annually to three times, with 420 pounds per acre 12-6-6 at each date. Calves
were shrunk overnight when placed on experiment and when weighed off the
Daily gains made on the two pasture types were quite similar, Table 3, but
total beef production was higher on the grass-legume combination.
Table 3. Results of three years grazing of Pensacola bahiagrass and
Pensacola bahiagrass combined with annual warm season legumes.
Pensacola Pensacola + Legume
Total feed per steer,
lbs annual 210 210
Daily gain, lbs.
Winter .42 .47
Summer .67 .72
Gain per acre, yearly, Ibs. 214 301
New Variety Grazing Trials.
Several grasses have been under trial with procedures essentially the
same as already described. Fertil.iation has been on a three times annually
basis, 420 pounds per acre in early spring, late spring, and in early to
mid-fall. All cattle have received the same amount of citrus pulp during
any year when those on the poorest pasture seemed to need additional
nutrition. No shrinkage was applied to at either initial or final date.
Table 4. Summer daily gain and yearlong beef production on grass pastures,
Summer Yearlong gain
Grass daily gains per acre, lbs.
1973 1974 1975 Av. 1973 1974 1975 Av.
Pangola .74 .94 -- .84 289 417 -- 353
U.F. 4 Stargrassq .80 1.16 .93 .96 376 550 592 506
Coastcross I -- 1.04 .85 .94 -- 490 492 491
Transvala .96 1.19 .81 .99 286 397 511 398
Common bermuda -- -- .98 -- -- 469 --
The purpose of these data is to show the reason for our interest in the
large-stemmed, non-rhizomatous Cynodon grasses that are being called "stargrass".
This name is being used in south and east Africa and in Latin American and it
seems a consistent thing to do the same in Florida.
The U. F. 4 stargrass has not been recommended because laboratory
analyses have shown this grass and other similar ones to have comparatively
high levels of prussic acid (HCN) potential in the fresh, highly fertilized
leaves and young stems. No problem has been found with extensive grazing
at Ona but cattle losses have been reported in Florida from the use of other
varieties of stargrass. Caution seems to be the best policy in this matter.
Management and Supplement Systems for Beef Cows-
The second phase of grazing trial research has been based on cow-calf
breeding herds managed on 40-acre units of pasture and given different mana-
gement patterns. Twenty-five mixed breed cows were kept year-round on the
same pasture units,,bred to calve January-April and culled in the fall if
they failed to conceive. Replacements consisted of open 2-year olds. Pasture
units were planned to be subdivided into four 10-acre blocks for rotation
purposes. Grazing was done on a basis of one week of use and three weeks of
regrowth. Many adjustments were required in the course of managing the pasture
variations. Hay was fed to each herd as needed in the spring months. Calves
were weighed and weaned in September. Weaning percentages were based on numbers
of cows in herd during breeding season. Eight systems were established, each
on 40 acres:
2/ Hodges, E. M., F. M. Peacock, H.L. Chapman, Jr. and R. E. L. Greene.
Forage and supplement systems for beef cows in south Central Florida.
Soil and Crop Sci. Soc. of Fla. Vol. 33:56-59.
1. Grass. All grass, fertilized spring and fall with 400 Ibs./A 12-6-6 at
2. Molasses. Same grass pasture plan with cows fed 5 pounds daily of forti-
fied blackstrap molasses during the mid winter period.
3. Hubam. 30 acres grass; 10 acres fall-seeded to Hubam sweetclover, this
area received only 0-8-24 fertilizer.
4. Aeschynomene "A". 20 acres grass; 20 acres managed for summer growth of
Aeschynomene, 0-8-24 fertilizer.
5. Aeschynomene "B". 20 acres grass; 20 acres managed for Aeschynomene,
6. Whiteclover. 30 acres grass; 10 acres irrigated whiteclover, 0-8-24
fertilizer with added potash.
7. Ryegrass. 30 acres grass; 10 acres fall-cultivated and seeded to rust-
resistant annual ryegrass, fertilized at planting with 400 lbs./A 16-8-8
and with extra nitrogen January and March, replanted to Pangola in summer.
8. Combination. 20 acres grass; 10 acres irrigated whiteclover; 10 acres
planted in spring to sorghuim-oudan hybrid and to ryegrass in following
The summary of performance on these treatments is shown in Table 5.
These treatments were labeled "systems" but they actually were too
simple to deserve being given this label. Hay was fed to fill in the gaps in
the forage supply. Quantity of hay fed on the treatments indicates the degree
of forage deficiency that came in the fall to spring period. It can be seen
that the most hay was fed on the legume treatments where a substantial period
of removal from grazing was a management necessity.
Weight increase per cow was a variable value but represented a plus factor
in considering pasture productivity. Replacement heifers made a great deal of
growth during the first year in the herd. Death losses were negligible in the
experiment, a fact to be considered in any extension of these data.
Weaning percentages showed large variations from year to year in the same
treatment. The whiteclover (Table 6) had 36 percent weaned calf crop during one
year, with no visible forage or other factor for explanation. This variation
emphasizes the difficulty inherent in pasture evaluations that are related to
Table 5. Production and supplementation
average, ARC, Ona, 1967-1972.
summary of herd management systems, yearly
Hay fed Weight increase Weaning Calf weaning Calf production Calf production
Systems per cow per cow percentage weight per cow per acre
--- -- -- ---
Table 6. Two years data on four forage management systems for cow-calf production,
Hay fed Weaned Calf Weaned calf
Treatment annually per cow calf weaning weight prod. per A
Ibs % ibs Ibs
Perennial Grass 479 81 450 227
Additional N 379 89 485 272
Ryegrass N 712 73 478 216
Clover + Reygrass 608 85 490 261
Calf weaning weight data show the relative strength of all the systems
as they were conducted in this trial. Variation in calf weight between the
two Aeschynomene treatments (Table 5) reveals the effect of soil and other
factors between pasture separated by no more than one-half mile.
Calf production per cow is presented as a matter of convenience and is
directly related to weaning weight and percentage.
The all-perennial grass system was the easiest to manage but did not
provide enough forage for winter and spring. Addition of fortified molasses
increased weaned calf production when substantial amounts of hay were
included in the diet. Hubam sweetclover was a-plus factor in three out of
five years. The shortages in forage supply were severe and require substant-
ial feeding of hay.
Both Aeschynomene units produced excellent summer-fall grazing in three
years and very little in two others. It seems that this legume, as well as
Hubam, should be viewed as special quality practices to be used in a forage
program on a relatively small percentage of the total pasture. The production
record on the whiteclover treatment was slowed by variations in clover growth
(in spite of seepage irrigation) and by low calving percentages apparently not
related to pasture condition.
Ryegrass growth was more consistent from year to year than the other
species brought into the perennial grass sods. This did not prevent a high
degree of year to year variation in production data of the ryegrass herd.
All factors considered, production was highest and most consistent in the
diverse ryegrass-sorghum-whiteclover treatment. The sorghum-sudan hybrid
practice did not fit into the system and was discontinued after three years.
Pastures for Cow-Calf Herds 1973-1975
The herds reported in the 1967-1972 experiment were continued with four
treatments, each repeated twice:
1. Grass. Perennial grass only (bermuda, Pangola, Bahia, star), fertilized
twice annually with 400 pounds per acre 16-8-8, 25 commercial-type on
40 acres, divided into four equal areas, grazed one week, three weeks
regrowth, hay as needed in winter and spring.
2. Extra nitrogen. Perennial grass as in #1 plus an additional 64 pounds per
acre nitrogen (N) annually.
3. Ryegrass. Perennial grass on 30 acres, 10 acres rust-resistant ryegrass
fertilized with 400 lbs./A 16-8-8 in fall plus 200 lbs./A ammonium nitrate
at each of two dates.
4. Combination. Perennial grass on 20 acres,10 acres ryegrass as in #3, 10
acres irrigated whiteclover with 300 Ibs./A 0-8-24 + 0.5% B203 and added
K20 when needed.
Two years of data are shown in Table 6. The current period of high costs'and
low returns makes it hard to build a case for heavy fertilizer rates, but there
was a response in weaning percentage, calf weight and calf production per acre.
No explanation is offered for the lower performance of the two herds of cattle
on the ryegrass treatment.
These cow-calf trials show that perennial grass pastures are the firm base
beneath our beef enterprise. They do not prove that any one forage plant.or
management system is the answer to everyone need. To the contrary, it is apparent
that a number of workable components are available for use in different situations
to upgrade animal nutrition and production efficiency. The relatively short term
data are presented here because they relate to our presentation. No effort will
be made in this discussion to interpret.