• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Introduction
 Review of literature
 Method of procedure
 Results
 Discussion
 Summary and conclusions
 Acknowledgement
 Literature cited














Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 659
Title: Unirrigated and irrigated alfalfa-oat-clover pasture for dairy cattle
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 Material Information
Title: Unirrigated and irrigated alfalfa-oat-clover pasture for dairy cattle
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 659
Physical Description: Book
Language: English
Creator: Marshall, Sidney P.
Myers, J. Mostella
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1963
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Bibliographic ID: UF00027639
Volume ID: VID00001
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Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 3
    Method of procedure
        Page 4
        Page 5
        Page 6
    Results
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Discussion
        Page 13
        Page 14
    Summary and conclusions
        Page 15
    Acknowledgement
        Page 16
    Literature cited
        Page 16
Full Text
etin 659
1963






-? 2,







Unirrigated and Irrigated, .
Alfalfa -Oat- Clover Pasture

for Dairy Cattle

Sidney P. Marshall ', -Mostella Myers


University of Florida
Agricultural Experiment Stations
J. R. Beckenbach, Director


Gainesville






















CONTENTS

Page


INTRODUCTION .
IN TRODUCTION ....-...-.........--------......---.. ------- .....-...........-..- .....-....-..... 3

REVIEW OF LITERATURE ....................-.-.. ...... ..------ ...... .......- .. 3

M ETHOD OF PROCEDURE .................-.-- ...-- ----- .....-----...-.... ............ 4

R ESU LTS ... ..-..-...... ... ...... ... --- --.... ..-- .. -.- -- -- 7

D ISCUSSION .......... .. ........ .. .... 13

SUMMARY AND CONCLUSIONS ... .....-. .............. .......----------------. 15

A CKNOWLEDGMENTS ... .. .......... ................... -- -----------------. 16

LITERATURE CITED .................... ... .. .. ........ ... --.....----- .- 16


Cover: Alfalfa predominates in the pasture mixture being grazed in
strips to maximize production and usage.








UNIRRIGATED AND IRRIGATED
ALFALFA-OAT-CLOVER PASTURE
FOR DAIRY CATTLE

SIDNEY P. MARSHALL AND J. MOSTELLA MYERS 1

INTRODUCTION
Quality pastures are a desirable source of feed for dairy cat-
tle. They are palatable, help maintain proper functioning of the
ruminant digestive processes, stimulate high production, and
enhance the Vitamin-A potency of milk.
Legumes generally are best quality forages for livestock. The
quality of succulent temporary grasses is good but is below that
of legumes. Permanent pasture grasses generally have a lower
nutritive value in cattle feeding programs.
The acreage of legume pastures grown in Florida is relatively
small as compared with about 2.5 million acres of improved
permanent pasture grasses. Summer temporary grass pastures
total about 50,000 acres, and oats and rye grown for winter
pasture or cover crops were reported to be 140,000 acres (6).2
Clovers have been seeded on over 250,000 acres of the improved
permanent pasture land. Although clovers produce excellent
quality forage, their soil moisture and climatic requirements
impose limitations on the areas where and seasons when they
will produce grazing. A legume or legume-grass mixed pasture
that is adaptable for growth on a wide range of soil types and
that will provide high-quality forage over a long period would
be beneficial. Since alfalfa possesses these qualities and has been
grown with success in Florida as an annual, it was selected as
the principal plant to be grown in a pasture mixture along with
oats and clovers for evaluation in a dairy feeding program. Sup-
plemental irrigation water was applied to comparable plots of
the pasture mixture during two growing seasons.

REVIEW OF LITERATURE
An early report from the Everglades Station (3) showed that
an Indian strain of alfalfa produced 18 tons of green forage per

SDairy Husbandman and Agricultural Engineer, Florida Agricultural
Experiment Stations.
2 Figures in parentheses refer to Literature Cited.








UNIRRIGATED AND IRRIGATED
ALFALFA-OAT-CLOVER PASTURE
FOR DAIRY CATTLE

SIDNEY P. MARSHALL AND J. MOSTELLA MYERS 1

INTRODUCTION
Quality pastures are a desirable source of feed for dairy cat-
tle. They are palatable, help maintain proper functioning of the
ruminant digestive processes, stimulate high production, and
enhance the Vitamin-A potency of milk.
Legumes generally are best quality forages for livestock. The
quality of succulent temporary grasses is good but is below that
of legumes. Permanent pasture grasses generally have a lower
nutritive value in cattle feeding programs.
The acreage of legume pastures grown in Florida is relatively
small as compared with about 2.5 million acres of improved
permanent pasture grasses. Summer temporary grass pastures
total about 50,000 acres, and oats and rye grown for winter
pasture or cover crops were reported to be 140,000 acres (6).2
Clovers have been seeded on over 250,000 acres of the improved
permanent pasture land. Although clovers produce excellent
quality forage, their soil moisture and climatic requirements
impose limitations on the areas where and seasons when they
will produce grazing. A legume or legume-grass mixed pasture
that is adaptable for growth on a wide range of soil types and
that will provide high-quality forage over a long period would
be beneficial. Since alfalfa possesses these qualities and has been
grown with success in Florida as an annual, it was selected as
the principal plant to be grown in a pasture mixture along with
oats and clovers for evaluation in a dairy feeding program. Sup-
plemental irrigation water was applied to comparable plots of
the pasture mixture during two growing seasons.

REVIEW OF LITERATURE
An early report from the Everglades Station (3) showed that
an Indian strain of alfalfa produced 18 tons of green forage per

SDairy Husbandman and Agricultural Engineer, Florida Agricultural
Experiment Stations.
2 Figures in parentheses refer to Literature Cited.






Florida Agricultural Experiment Stations


acre in two cuttings within 120 days after planting. Hairy Pe-
ruvian alfalfa grew slower at first, but produced almost as much
forage as did the Indian strain at second cutting. Alfalfa has
since been grown in Florida as an annual.
Plant diseases have been a major factor in causing loss of
stand and the necessity for replanting alfalfa annually. How-
ever, work at the West Florida Station (4) indicated that stage
of growth at cutting influenced livability. Cutting at one-tenth
bloom or later as compared to cutting at the prebud stage in-
creased the percentage of plants overwintering from 10 percent
to 50 to 60 percent but reduced forage yield by about 1,000 pounds
per acre.
Recent work at the Florida Agricultural Experiment Station
(5) revealed that an experimental strain of alfalfa selected for
persistence was equal to the commonly grown commercial hairy
Peruvian in forage production the first year after seeding and
gave significantly higher yields the second and third year due
to better stands. Alfalfa, primarily hairy Peruvian and Chilean
varieties, grown in Florida in 1961, was estimated at 30,000
acres (7).
At Lewisburg, Tennessee (8), irrigated alfalfa-ladino-or-
chardgrass mixed pasture provided 49 percent more cow days
of grazing, and cows produced 4,302 pounds per acre, or 54
percent, more 4 percent fat-corrected milk on irrigated than
on unirrigated pasture.
Work at the Florida Station (9) indicated that returns per
acre inch of irrigation water applied were greater for legume
pasture than for permanent pasture grass. Since the experi-
mental pasture mixture to be tested would produce quality for-
age, and since alfalfa is a deep rooted plant, it was thought that
irrigation might produce favorable returns. Therefore, the
study was undertaken to determine the yield of total digestible
nutrients, quality, distribution of feed supply, and net returns
that may be realized from unirrigated and irrigated pasture
under an intensive grazing management program.

METHOD OF PROCEDURE

A pasture mixture of hairy Peruvian alfalfa, oats, and clovers
was seeded annually in September or October for four years on
Scranton loamy fine sand at Hague, Florida. During 1954-55,
a 2-acre unirrigated pasture was seeded and grazed. Beginning
in 1955, irrigation was included as a variable and during two






Alfalfa-Oat-Clover Pasture for Dairy Cattle


years (1955-56 and 1956-57) the effect of irrigation on the pas-
ture mixture was studied using two comparable 1.6-acre plots.
The area adjacent to the source of irrigation water proved to be
inadequately drained during prolonged periods of exceedingly
heavy rainfall as occurred in 1958 and 1959. Development of
needed drainage was precluded by property boundary, and the
pasture was planted on the same soil type in a better drained
area in 1960. Distance of this area from the irrigation well
made irrigation unfeasible in 1960. Seeding rates per acre used
to establish the pasture mixture each year and the planting
dates are shown in Table 1.

TABLE 1.-PLANTING DATES AND SEEDING RATES, BY YEARS.

Seed per Acre, Pounds
10/6/54 9/15/55 9/15/56 10/22/59:*

Oats* .................................... 47 24 24 32
A lfalfa --.. -------... ............. 11 12 12 16
Kenland red clover .......... 6 7 7 8
California bur clover ....... 5 5 5 -
White clover ......... 4 -
Ladino clover ..... .......... 1.5 1.5 -

Arlington was used in 1956 and Seminole during the other years.
** Date reseeded. Part of stand from September 25 planting wtas lost during a period
of heavy rainfall in October.

Prior to seeding, the land was limed to a pH of about 6.5,
and applications were made of superphosphate, muriate of pot-
ash, and agricultural borax. Top-dressings of muriate of potash
were applied during the grazing season. The amounts of plant
nutrients applied per acre are shown in Table 2. Seventy-two
pounds of nitrogen were applied per acre prior to grazing in
1954. The resulting accelerated growth of oats stimulated by
added nitrogen caused overshading of legumes, and nitrogen
fertilization was discontinued.
During the years when irrigation was a treatment, one plot
received only natural rainfall and served as the control. Sup-
plemental water was applied to the other plot when approxi-
mately 75 percent of the available moisture had been removed
from the top 12-inches of soil during the first two months after
seeding before a deep root system was established. Irrigation
water was applied when the same soil moisture level was reached
in the top 18 inches of soil during the remaining part of the
growing season. The amount of water applied was that calcu-






Florida Agricultural Experiment Stations


lated to be needed to bring the soil moisture of the top 24-inch
strata to field capacity. Soil samples were taken from 0 to 6-
inch, 6 to 12-inch, 12 to 18-inch, and 18 to 24-inch depths in
the irrigated and unirrigated plots at intervals of about one
week. The moisture content of samples from the irrigated plots
was used in determining the time to irrigate and the amount
of water to apply. Supplemental water was applied with a port-
able sprinkler system.

TABLE 2.-PHOSPHOROUS, POTASH, AND BORAX APPLIED PER ACRE EACH
PASTURE YEAR TO UNIRRIGATED AND IRRIGATED PLOTS.

Nutrients, Pounds per Acre
Number of
Year Prior to seeding As top-dressings Top-dressings
P20O K2O B,O, KO

1954-55*: ...... 136 136 8 150 3
1955-56 ......... 100 100 8 148 2
1956-57 ......... 100 100 8 74 1
1959-60 .......... 108 108 8 162 2

Seventy-two pounds of nitrogen applied per acre prior to grazing.

Grazing was begun when the forage was about 10 inches
tall and was continued either until the supply was inadequate
to justify pasturing or until mid-September when the land was
prepared for reseeding. During the first three years the pasture
was grazed when the alfalfa was in the prebud stage. How-
ever, in 1960 alfalfa frequently was in the bud stage, and oc-
casionally there were a few blossoms at grazing time. Except
for this difference, grazing management was uniform between
years and between pastures.
The pastures were dusted twice with parathion during the
1956-57 pasture season for control of the spotted alfalfa aphid
(Therioaphis maculata Buckton).
Open Jersey, Guernsey, and Holstein heifers were used to
graze the pasture. Each plot was grazed rotationally with sep-
arate groups of heifers by exposing narrow strips of forage to
the animals twice daily (10). The number of animals grazing
each pasture was adjusted in accordance with available supply
and anticipated growth of forage. Shade, drinking water, salt,
steamed bonemeal, and an iron-copper-cobalt mineral mixture
were provided in each pasture. Body weights were taken on
three consecutive days at the beginning, at the end, and at 28-
day intervals during the experiment.






Alfalfa-Oat-Clorer Pasture for Dairy Cattle


RESULTS
Rainfall and Irrigation Water Applied.-Precipitation was
subnormal during each of the first three pasture seasons, and
was quite deficient in some periods. Rainfall was 7 inches be-
low normal (1931-55 average) in the 1954-55 grazing season.
Low soil moisture influenced pasture yield particularly during
late spring and summer.
In the 1955-56 growing season precipitation totaled 31 inches,
which was 21 inches below normal. The irrigated pasture re-
ceived three applications of water prior to initiation of grazing
and 11 during the grazing season for a total of 15.1 inches. Rain-
fall was unusually low in late 1956 and early 1957. Nine irriga-
tions supplying 11.3 inches of water were made prior to initia-
tion of grazing, and 9 inches of water were applied in seven ir-
rigations during the 1957 grazing season.
Precipitation was 3 inches above normal for the 1959-60 sea-
son, and the pasture did not appear to suffer from insufficient
soil moisture. Heavy rains in June waterlogged the soil, and
this appeared to have retarded growth of the alfalfa. The
amounts and distribution of rainfall are shown in Figure 1.
Grazing Periods and Total Digestible Nutrients Obtained
per Acre.-Grazing was initiated on unirrigated pastures from
November 17 to January 12, except in 1956, when it was de-
layed until April 20 by drought, disease, and cold weather. The
intervals from plantings until grazing ranged from 56 to 82
days, except for 1955-56, when it was 147 days. Short inter-
vals between seeding and grazing were associated with mild
weather and adequate soil moisture.
The four grazing seasons on unirrigated pasture averaged
202 days in length and were continuous in 1957 and 1960. There
was a seven-day interruption due to dry weather and disease in
1954-55 and two interruptions totaling 90 days caused by cold
and/or dry weather in 1955-56. Grazing was concluded in mid-
September of two years in order to prepare the land for reseed-
ing. Termination of grazing in mid-August and mid-July the
other two years was caused by slow growth and a poor stand
of attenuated alfalfa plants due to diseases.
Calculated amounts of total digestible nutrients (1) obtained
per acre from unirrigated pasture averaged 4,585 pounds per
acre for four years and ranged from 1,670 to 7,098 pounds per
year.










TABLE 3.-VALUE OF UNIRRIGATED AND IRRIGATED ALFALFA-OAT-CLOVER PASTURES GRAZED BY DAIRY HEIFERS, BY YEARS.


1954-55 1955
Unirrigated Unirrigated


Grazing season began -..... .......... ..
Grazing season ended ............... ...
Length of grazing season, days ...................
Number of pasture rotations ..................

Av. initial weight of heifers, lbs .........
Av. daily gain per animal, lbs ..............
Gains expressed as percentage of
normal growth rate** .................
Av. gains per acre, lbs.......... ...............

T.D.N. obtained from pasture, per acre, lbs.
Alfalfa hay equivalent obtained from
pasture, per acre, tons ...........


Calculated feed replacement value of
forage, per acre ..........................
Calculated cost of pasture production
excluding irrigation, per acre ...............
Feed replacement value increase per
acre inch of water applied .................


-1-54
-20-55
286
9


-17-55
-17-56
215
9


453 459*


1.3

145
755

5,227

5.2


$247

$ 89


1.4

141
642

4,344

4.3


56
Irrigated

11-3-55
9-17-56
284
9

438


1956-
Unirrigated

4-12-57
7-12-57
91
3

511*


57
Irrig

2-20
7-12
14


1.3 1.3


3,68


5,547 1,670

5.5 1.7


ated


1959-60
Unirrigated


-57 1-12-60
-57 8-18-60 .
12 218
4 6

0 421
1.6 1.0

24 100
)1 917

87 7,098

3.7 7.1
'"-t


$288

$ 67


$ 3.64


$ 4.19


* Higher average initial weight of animals on unirrigated pasture was due to gains made subsequent to date grazing was begun on irrigated pasture.
** The standard growth curve for dairy heifers reported by Ragsdale (Mo. Agr. Exp. Sta. Bul. 336) was used for comparison.






Alfalfa-Oat-Clo er Pasture for Dairy Cattle


Grazing on irrigated pastures was begun 14 and 51 days
earlier during the respective two years (1955 and 1957) but
terminated on the same dates as the unirrigated. Irrigation in-
creased the number of calendar days the pasture was grazed by
69 in 1955-56 and by 51 in 1957. Increases in yield of total di-
gestible nutrients per acre by irrigation were 1,203 pounds in
1955-56 and 2,017 pounds in 1957. A summary of results of the
grazing experiments with unirrigated and irrigated alfalfa-oat-
clover pastures is shown in Table 3.
Distribution of Feed Supply and Carrying Capacity of the
Pasture.-In general, the amount of total digestible nutrients
obtained from the pasture was highest in spring and then de-
clined during the summer. The yield of nutrients usually was
low during the late fall and winter periods. In addition to sea-
sonal variations in feed supply, there were year to year fluctu-
ations in distribution. Soil moisture, temperature (cold weath-
er), and diseases were important factors influencing these vari-
ations. The amounts of total digestible nutrients obtained from
the pasture per acre biweekly are shown in Figure 1. The base
line in the figure represents a suggested uniform level of total
digestible nutrients per acre selected for the purpose of calcu-
lating the acreage of unirrigated pasture to plant for a herd.
Further discussion of the base line is presented later in this
section.
Dry weather was responsible for suspension of grazing on
unirrigated pasture for seven days in August 1955. Cold dam-
age to the pasture during the winter of 1955-56 necessitated re-
moval of animals from the irrigated plots for 35 days. Dry and
cold weather were responsible for a 62-day interruption in graz-
ing of the unirrigated pasture during the winter, and dry weath-
er caused a 28-day suspension in April 1956.
Severe freezes in December 1956 and January 1957 along
with an epidemic of Stemphylium leaf spot were responsible for
a delay in grazing on the irrigated pasture until February 20.
These factors plus dry weather delayed beginning of grazing
on the unirrigated pasture until April 1957.
In determining the acreage of pasture to grow, both the level
and uniformity of supply of total digestible nutrients it will
provide are important. These factors also will influence the
amounts of supplemental feeds the herd will need and the quanti-
ty of surplus forage likely to occur. Each person must assess
these factors in relationship to his resources in arriving at the
acreage of pasture to plant. To illustrate the principle involved








10 Florida Agricultural Experiment Stations


in such an assessment, a study was made of the data in Figure
1. Two hundred and seventy-five pounds of total digestible nu-
trients biweekly from the pasture (represented by the base
line) was considered to be a reasonable uniform level to employ
in calculating the approximate maximum acreage of unirrigated
pasture to grow. A level of 300 pounds of total digestible nu-
trients biweekly (not shown in the figure) appeared to be logi-


RAINFALL
IN.


1954-55


I- RRIGATED --BASE LINE
----- UNIRRIGATED "- k
11 I
RAINFALL I --
-- .V. 5.
\ ,, \

,.. I I I I 1 I I I


1955-56


1956-57


1959-60
900-
800- / \
oo-
700-
600 -
00-I
500 -
500 --
00 __. ._._._._. .. .. ...-.-
200- ---

NOV. I DEC. JAN. I FED. I MAR.I APR. I MAY I JUNE I JULY AUG. SEPT.


Fig. 1.-Total digestible nutrients obtained biweekly per acre from alfalfa-
oat-clover pasture. Rainfall is shown by three-day periods.






Alfalfa-Oat-Clover Pasture for Dairy Cattle


cal for the irrigated pastures. At these nutrient levels, a 1,000-
pound cow obtaining total digestible nutrients from pasture
needed to support body maintenance and 12 pounds of her daily
production of 4 percent milk would require 0.60 acre of unirri-
gated or 0.55 acre of irrigated pasture. To supply nutrients
required to support maintenance and to make normal growth,
a 700-pound heifer would require 0.49 acre of unirrigated or
0.45 acre of irrigated pasture.
Employing a total digestible nutrient level of 275 pounds
per acre biweekly (shown by base line in Figure 1) as the amount
needed for grazing purpose from unirrigated pasture, an annual
average of 3,378 pounds would have been utilized for grazing.
An average of 1,207 pounds of total digestible nutrients annually
in excess of grazing needs would have been available for preser-
vation and storage.
Using 300 pounds of total digestible nutrients biweekly as
the level needed for grazing from irrigated pasture, an annual
average of 3,623 pounds would have been grazed, and 985 pounds
would have been available for harvest. Comparable average
annual values calculated using a 275-pound biweekly level for
unirrigated pastures would have been 2,571 and 435 pounds,
respectively, for the same two years.
Body Weight Gains.-Annual body weight gains of heifers
on unirrigated pastures averaged 637 pounds per acre of pasture
grazed and ranged from 233 to 917 pounds for the different pas-
ture seasons. Daily gains averaged 1.2 pounds, which was 128
percent of the Missouri Standard (11). During the first three
years when alfalfa was grazed in the prebud stage, daily gains
averaged about 1.3 pounds; this growth rate was about 143
percent of the Missouri Standard. In 1960, alfalfa frequently
was in the bud stage and occasionally in early bloom when
grazed. Utilization at a later stage of growth was accom-
panied by a slower animal growth rate (1.0 pound daily) and
a higher yield of total digestible nutrients per acre.
Pasture irrigation increased yield of total digestible nutri-
ents, and this was accompanied by corresponding increases in
average weight gain per acre. Animals on irrigated pasture
gained an average of 159 pounds more per acre in 1955-56 and
368 pounds more per acre in 1956-57 than those on unirrigated
pasture. Growth rate, when expressed as percentage of the
Missouri Standard, was lower for animals grazing irrigated
pastures than for those on unirrigated during comparable years.
Higher average initial weight of animals on unirrigated pasture






Florida Agricultural Experiment Stations


was due to growth made during intervals between initiation
of grazing on the respective pastures.
Hay Equivalent and Feed Replacement Value of the Pasture.
-Since most of the forage consumed was alfalfa, and the qual-
ity of oats and clover forage was similar to that of alfalfa, this
hay was used as the reference roughage in evaluating the feed
obtained from the pasture. The average total digestible nutri-
ents obtained per acre from unirrigated pastures annually was
equivalent to 4.6 tons of hay. For 1955-56 and 1956-57 seasons
the annual average total digestible nutrients per acre from un-
irrigated pastures was equivalent to 3.0 tons of hay per acre
as compared to 4.6 tons for that from irrigated pastures.
In calculating feed replacement value of the pasture, consid-
eration was given to the fact that the roughage requirements
of a herd are rather uniform under practical conditions. The
total digestible nutrient level of the base line in Figure 1 was
used to represent the amount needed from unirrigated pasture,
and that above the base line was considered as surplus, which
could be preserved as stored forage. The hay equivalent that
could be utilized as grazed forage was valued at $52 per ton,
and that as surplus valued at $26 per ton.
The calculated annual feed replacement value of unirrigated
pasture per acre ranged from $83 to $288 and averaged $206
for the four years. During the two seasons when irrigation was
a variable, the calculated feed replacement value annually per
acre averaged $214 for the irrigated pasture and $144 for the
unirrigated.
Calculated Production Costs and Net Returns.-Prevailing
prices for fertilizers and land rent were employed in calculating
pasture production costs. Assessments for cultural practices
were in accordance with charges for local custom work where
pastures are 10 acres or larger. Fertilizer costs per ton were:
superphosphate, 20 percent, $30; muriate of potash, 60 percent,
$58; agricultural borax, $113; and ammonium nitrate, $80. Seed
cost per hundred-weight were: alfalfa, $35; Kenland red clover,
$55; bur clover, $50; white clover or Ladino clover, $105; and
oats, $5.50. Assessments per acre for cultural practices were
breaking land, $3.25; harrowing, $1.70; spreading fertilizer.
$1.50; applying topdressing, $1.25; seeding, $1.25; and mowing,
$1.25. Calcic limestone applied on pasture was $5 per ton, and
dolomite limestone $7 per ton. Land rent was $8 per acre, and
total cost of dusting pasture with parathion was $1.90 per acre.






Alflfa-Oat-Clo rer Pasture for Dairy Cattle


Calculated production costs of unirrigated pastures ranged
from $61 to $89 per acre for different years and averaged $70.50
per acre annually. Production costs of total digestible nutrients
derived from unirrigated pastures averaged 1.54 cents per pound.
Calculated annual feed replacement value of pasture per acre
averaged $206, and the net return $135.50 per acre.
Annual production costs per acre, excluding irrigation ex-
penses, averaged $63 for 1955-56 and 1956-57. Average annual
feed replacement value per acre of pasture for the two years was
$144 for the unirrigated and $214 for the irrigated. The in-
crease in feed replacement value averaged $3.95 per acre inch
of water applied.

DISCUSSION
Alfalfa in combination with oats and clovers provided ex-
cellent pasture with an average annual yield of 4,585 pounds of
total digestible nutrients per acre obtained from unirrigated pas-
tures in four seasons. During two years when comparable
pasture plots were irrigated, averages of 1,023 and 2,017 pounds
more total digestible nutrients were obtained per acre from the
irrigated pastures during the respective grazing seasons. Graz-
ing was begun 14 and 51 days earlier on irrigated pastures dur-
ing the respective seasons, and the supply of feed from them
was more uniform. Irrigation did not improve quality of for-
age as indicated by growth response of heifers grazing the pas-
tures. The increase in calculated feed replacement value of
feed produced per acre inch of water applied averaged $3.95.
This value exceeds the commonly employed irrigation cost range
figures of $2 to $3.50 per acre inch for sprinkler type irrigation
and of $0.25 to $0.75 for subirrigation. Rainfall was subnormal
during the two years when supplemental irrigation studies were
made.
Alfalfa furnished most of the forage during fall and winter
and practically all of the forage during spring and summer.
Oats furnished a significant but minor proportion of the graz-
ing in the fall and during mild winter. Oats usually grew more
rapidly than alfalfa, and stem joints frequently had formed by
the time animals were placed on the pasture. Grazing at this
growth stage impaired regrowth, and freezes following initial
grazings killed most of the oat stubbles during two seasons.
Stands of clovers were poor due to overshading by the taller
plants. They produced very little forage except along the bor-






Florida Agricultural Experiment Stations


ders and in spots where the alfalfa stand was thin. Inclusion
of a reseeding clover in the initial planting might be justified
as a measure to insure a good forage stand.
Seeding of the pasture mixture was delayed until the latter
part of September to avoid loss of oats by diseases during hot
weather. Under practical conditions alfalfa could be seeded
alone in August and thereby could provide earlier grazing. If
oats pasture is desired, it could be seeded separately and heavy
nitrogen application made early to stimulate early growth for
fall grazing. Land seeded to oats then could be used for pro-
duction of summer annual pastures such as millet.
Wide variability in distribution of feed supply from the
pasture in relationship to a rather constant level of need by a
herd is a major problem influencing the acreage to plant and
profitableness of the pasture. These variations (Figure 1) were
caused primarily by weather conditions and by plant diseases.
Some improvement in yield and distribution of feed supply was
accomplished by irrigation.
If acreage planted is adequate to meet herd needs for forage
only during periods of peak forage production, then large defi-
ciencies will occur most of the season. However, practically all
of the forage would be used for grazing purpose, and a high feed
replacement value would be realized for all produced. Con-
versely, if sufficient acreage is grown to provide forage needs
during periods of low production, then large surpluses would
occur during favorable growing seasons. The lower utilization
value of this surplus would reduce profitableness per acre. Fac-
tors important in determining the acreage of pasture to plant
include: acreage of land available; productivity of pasture; and
availability, quality, and costs of other roughages.
Plant diseases, including stemphylium leaf spot, root disease,
and crown disease, were responsible primarily for a decline in
amount of forage obtained from alfalfa during the summer and
for the necessity of replanting alfalfa each fall (2). A disease-
resistant, perennial alfalfa should increase both the annual yield
of nutrients and improve the seasonal distribution of feed supply.
Infestations of spotted alfalfa aphids necessitated dusting
for control in December 1956 and January 1957. Another aphid
population build-up occurred in February. However, the weather
turned warm and humid, and this infestation was reduced and
controlled primarily by fungi parasitism. Although spotted al-
falfa aphids were found occasionally during warm weather, their
control did not constitute a problem during these seasons.






Aalfalf-Oat-Clover Pasture for Dairy Cattle


SUMMARY AND CONCLUSIONS
Irrigated and unirrigated pasture mixtures of alfalfa, oats,
and clovers grown on Scranton loamy fine sand were grazed with
separate groups of dairy heifers during two years. Unirrigated
pasture mixtures were grazed during two additional years. Total
digestible nutrients obtained annually per acre averaged 4,617
pounds for the irrigated pasture, which was 1,520 pounds above
that obtained from the unirrigated. Total digestible nutrients
obtained per acre from the unirrigated pasture during four years
averaged 4,585 pounds and ranged from 1,670 to 7,098 pounds
per year.
Grazing was begun 14 and 51 days earlier on irrigated pas-
tures than unirrigated during the two years, but grazing ter-
minated on the same dates. Distribution of feed supply was
more uniform on irrigated pasture, but there was no improve-
ment in average daily gains of animals grazing this forage.
Annual body weight gains per acre for the two pasture sea-
sons averaged 701 pounds for heifers grazing irrigated pasture
and 438 pounds for those grazing unirrigated. Growth rate of
the animals, expressed as percentage of the Missouri Standard,
was 128 percent for those on irrigated pasture and 142 percent
for those on unirrigated. During the four grazing seasons on
unirrigated pasture the heifers made annual average gains of
637 pounds per acre, and their growth rate averaged 128 per-
cent of the Missouri Standard.
Feed replacement value of the unirrigated pasture was cal-
culated as $206 per acre and the net return as $135.50 per acre.
Total production cost was calculated at $70.50 per acre. Pro-
duction cost of total digestible nutrients from the unirrigated
pasture averaged 1.54 cents per pound.
Average annual applications of 17.7 inches of water during
two years, in which precipitation was subnormal, increased the
calculated feed replacement value of the pasture $70 per acre.
This average increase in value of $3.95 per acre inch of water
applied was considered to be in the profitable range for low-cost
sprinkler-type irrigation operations.
Alfalfa supplied most of the forage in the pasture mixture
during fall and winter and practically all during spring and sum-
mer. Oats furnished a minor portion of the forage during fall
and winter. Clovers produced very little forage due to over-
shading by alfalfa and oats. For pasture purpose, it is sug-
gested that alfalfa be grown alone or in combination with a re-






Florida Agricultural Experiment Stations


seeding clover. If oat pasture is desired, it could be seeded sep-
arately and fertilized heavily to stimulate early growth for fall
grazing.
Low alfalfa plant populations in late summer made annual
reseedings advisable. Reduction in stand of alfalfa plants ap-
parently was caused by diseases.


ACKNOWLEDGMENTS

D. E. McLeod and G. B. Killinger advised on agronomic and
fertilization procedures. A. N. Tissot identified insect pests and
advised on their control. Phares Decker identified plant dis-
eases. H. L. Somers assisted with management of cattle and
pastures, and T. A. Monday operated the irrigation system dur-
ing the experiment.


LITERATURE CITED
1. Amer. Soc. Agron., Amer. Dairy Sci. Assoc., Amer. Soc. Anim. Prod.,
and Amer. Soc. Range Mgmt. Joint Committee. Pasture and range
research techniques. Agron. J. 44:39-50. 1952.
2. Decker, Phares. Private communication. 1961.
3. Fla. Agr. Exp. Sta. Ann. Rept. 1930:197-98.
4. Fla. Agr. Exp. Sta. Ann. Rept. 1959: 377.
5. Fla. Agr. Exp. Sta. Ann. Rept. 1961: 51.
6. Killinger, Gordon B. Improved and temporary pastures. Fla. Agr.
Exp. Sta. Res. Rept. 8:1:33-35. 1963.
7. Killinger, Gordon B. Clover and alfalfa. Fla. Agr. Exp. Sta. Res.
Rept. 8:1: 41. 1963.
8. Lush, R. H., A. G. Van Horn, and E. J. Chapman. Pasture irrigation.
Proc. Assoc. Sou. Agr. Workers 50th Ann. Convention: 200. 1953.
9. Marshall, Sidney P., and J. Mostella Myers. Irrigation of white clover-
pangolagrass pasture for dairy cows. Fla. Agr. Exp. Sta. Bul. 607.
1959.
10. Mitchell, W. G. "Ribbon Grazing" brings more milk. Prog. Farmer.
Ga.-Ala.-Fla. Ed. 70:9: 28. 1955.
11. Ragsdale, A. C. Growth standards for dairy cattle. Mo. Agr. Exp.
Sta. Bul. 336. 1934.






Florida Agricultural Experiment Stations


seeding clover. If oat pasture is desired, it could be seeded sep-
arately and fertilized heavily to stimulate early growth for fall
grazing.
Low alfalfa plant populations in late summer made annual
reseedings advisable. Reduction in stand of alfalfa plants ap-
parently was caused by diseases.


ACKNOWLEDGMENTS

D. E. McLeod and G. B. Killinger advised on agronomic and
fertilization procedures. A. N. Tissot identified insect pests and
advised on their control. Phares Decker identified plant dis-
eases. H. L. Somers assisted with management of cattle and
pastures, and T. A. Monday operated the irrigation system dur-
ing the experiment.


LITERATURE CITED
1. Amer. Soc. Agron., Amer. Dairy Sci. Assoc., Amer. Soc. Anim. Prod.,
and Amer. Soc. Range Mgmt. Joint Committee. Pasture and range
research techniques. Agron. J. 44:39-50. 1952.
2. Decker, Phares. Private communication. 1961.
3. Fla. Agr. Exp. Sta. Ann. Rept. 1930:197-98.
4. Fla. Agr. Exp. Sta. Ann. Rept. 1959: 377.
5. Fla. Agr. Exp. Sta. Ann. Rept. 1961: 51.
6. Killinger, Gordon B. Improved and temporary pastures. Fla. Agr.
Exp. Sta. Res. Rept. 8:1:33-35. 1963.
7. Killinger, Gordon B. Clover and alfalfa. Fla. Agr. Exp. Sta. Res.
Rept. 8:1: 41. 1963.
8. Lush, R. H., A. G. Van Horn, and E. J. Chapman. Pasture irrigation.
Proc. Assoc. Sou. Agr. Workers 50th Ann. Convention: 200. 1953.
9. Marshall, Sidney P., and J. Mostella Myers. Irrigation of white clover-
pangolagrass pasture for dairy cows. Fla. Agr. Exp. Sta. Bul. 607.
1959.
10. Mitchell, W. G. "Ribbon Grazing" brings more milk. Prog. Farmer.
Ga.-Ala.-Fla. Ed. 70:9: 28. 1955.
11. Ragsdale, A. C. Growth standards for dairy cattle. Mo. Agr. Exp.
Sta. Bul. 336. 1934.




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