• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Introduction
 Review of literature
 Whiteclover-pangolagrass pastu...
 Whiteclover-coastal bermudagrass...
 General discussion
 Summary and conclusions
 Literature cited














Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 613
Title: Whiteclover-pangolagrass and whiteclover-coastal Bermudagrass pastures for dairy heifers
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Title: Whiteclover-pangolagrass and whiteclover-coastal Bermudagrass pastures for dairy heifers
Series Title: Bulletin - University of Florida Agricultural Experiment Station ; 613
Physical Description: Book
Language: English
Creator: Marshall, Sidney P.
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1959
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Table of Contents
    Front Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Review of literature
        Page 3
    Whiteclover-pangolagrass pasture
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
    Whiteclover-coastal bermudagrass pasture
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
    General discussion
        Page 18
        Page 19
    Summary and conclusions
        Page 20
    Literature cited
        Page 21
        Page 22
Full Text


November 1959


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
JOSEPH R. BECKENBACH, Director
GAINESVILLE, FLORIDA






Whiteclover-Pangolagrass and

Whiteclover-Coastal Bermudagrass

Pastures for Dairy Heifers

SIDNEY P. MARSHALL
Dairy Husbandman, Florida Agricultural Experiment Station


Fig. 1.-Whiteclover is one of the most nutritious forages for dairy cattle.


Bulletin 613


















CONTENTS
Page
IN TRODUCTION .... .... ... .................. ....... ...... 3
REVIEW OF LITERATURE ..........................................
WHITECLOVER-PANGOLAGRASS PASTURE ........................................ 4
P procedure .. ......... ... ... .... .. ... .. .. .. .. ... ..... 4
R esu lts ..... ......... ... ........ .... ... ... .......... ........... ....... .. 7
Grazing Periods and Total Digestible Nutrients Obtained per
A cre .......................... ......... .... .. 7
Composition of Forage Samples .................................... 7
Distribution of Feed Supply and Carrying Capacity of the
Pasture .... .. ...... ... ....... 8
Body W eight Gains ....................... ... ....... ..... 11
Hay Equivalents and Feed Replacement Value of the Pasture.. 11
Calculated Production Costs and Net Returns ........................ 12
WHITECLOVER-COASTAL BERMUDAGRASS PASTURE ................................... 12
P procedure ... .. ....... ........... ........ ... .. 12
R results .......... ... .. ....... ...... .. .. .. .. .. .. .............- 13
Grazing Periods and Total Digestible Nutrients Obtained per
A cre ...... .. .... .. .... ............ 13
Composition of Forage Samples ~..... .... ...... 13
Distribution of Feed Supply and Carrying Capacity of the
Pasture ....................... .....--- 15
Body W eight Gains ...... .... ..... ... ----- --.. -- ---..... 17
Hay Equivalents and Feed Replacement Value of the Pasture ... 18
Calculated Production Costs and Net Returns ................. 18
GENERAL DISCUSSION .. ..- .. ..... ...... ..--..... ....-. 18
SUMMARY AND CONCLUSIONS ............. ..- ...-- ....-.....--..----- 20
ACKNOWLEDGMENT .... ..... ..-. ....--. ... -.. 21
LITERATURE CITED ...-... ........ ....-...... .. .........--.-. 21








Whiteclover-Pangolagrass and

Whiteclover-Coastal Bermudagrass

Pastures for Dairy Heifers

SIDNEY P. MARSHALL

INTRODUCTION

The objective in raising animals for dairy herd replacements
is to grow well-bred calves into healthy cows of adequate size
at a low cost. A satisfactory, economical replacement program
is dependent upon the utilization of relatively inexpensive feed-
stuffs and upon the animals growing continuously and rapidly.
Studies showed that well-developed heifers ready to calve at an
early age (22 to 25 months) produced more milk through 7
years of age than did others calving at later ages (2).1
Pastures generally are the cheapest source of feed for cattle.
Animals between the ages of 6 months and calving are able to
obtain most of their nutritive requirements from high quality
roughages. Yet when permanent pasture grasses have been
the sole source of feed, dairy heifers generally have made sub-
normal growth. Therefore, this study was undertaken to de-
termine the rate of growth that heifers would make on white-
clover-pangolagrass and on whiteclover-Coastal bermudagrass
pastures under programs of intensive grazing management and
liberal fertilization. The yield of total digestible nutrients.
quality of forage, distribution of feed supply and net returns
also were determined for each pasture.

REVIEW OF LITERATURE
Reports of grazing experiments with dairy heifers on pan-
golagrass or Coastal bermudagrass alone or in combination with
whiteclover have not been observed in the literature.
Coastal bermudagrass fertilized with 600 pounds of 6-6-6
plus 200 pounds of nitrogen per acre was grazed 1 year with
lactating cows at the Clemson station (14). The cows produced
an average of 31.5 pounds of milk daily, which was 96 percent


'Italic figures in parentheses refer to Literature Cited.








Whiteclover-Pangolagrass and

Whiteclover-Coastal Bermudagrass

Pastures for Dairy Heifers

SIDNEY P. MARSHALL

INTRODUCTION

The objective in raising animals for dairy herd replacements
is to grow well-bred calves into healthy cows of adequate size
at a low cost. A satisfactory, economical replacement program
is dependent upon the utilization of relatively inexpensive feed-
stuffs and upon the animals growing continuously and rapidly.
Studies showed that well-developed heifers ready to calve at an
early age (22 to 25 months) produced more milk through 7
years of age than did others calving at later ages (2).1
Pastures generally are the cheapest source of feed for cattle.
Animals between the ages of 6 months and calving are able to
obtain most of their nutritive requirements from high quality
roughages. Yet when permanent pasture grasses have been
the sole source of feed, dairy heifers generally have made sub-
normal growth. Therefore, this study was undertaken to de-
termine the rate of growth that heifers would make on white-
clover-pangolagrass and on whiteclover-Coastal bermudagrass
pastures under programs of intensive grazing management and
liberal fertilization. The yield of total digestible nutrients.
quality of forage, distribution of feed supply and net returns
also were determined for each pasture.

REVIEW OF LITERATURE
Reports of grazing experiments with dairy heifers on pan-
golagrass or Coastal bermudagrass alone or in combination with
whiteclover have not been observed in the literature.
Coastal bermudagrass fertilized with 600 pounds of 6-6-6
plus 200 pounds of nitrogen per acre was grazed 1 year with
lactating cows at the Clemson station (14). The cows produced
an average of 31.5 pounds of milk daily, which was 96 percent


'Italic figures in parentheses refer to Literature Cited.






Florida Agricultural E.periment Stations


of their expected production. They obtained 2,663 pounds of
total digestible nutrients per acre from the pasture.
At the Georgia Coastal Plain Station (10), 4 plots of Coastal
bermudagrass were fertilized with 350 pounds of 0-14-12 per
acre. Two of these plots were top-dressed with 50 pounds of
nitrogen per acre and the other 2 with 300 pounds per acre.
Carrying capacity of the pastures averaged 1.1 and 1.7 cows
per acre, respectively. There was no significant difference in
milk production by cows grazing the plots receiving the different
levels of nitrogen fertilization.
Coastal bermudagrass pasture was grazed an average of 256
cow days per acre at the Mississippi station (4). Milk pro-
duction per cow overaged 36.1 pounds daily.
Pangolagrass and Coastal bermudagrass pastures fertilized
annually with 900 pounds per acre of 9-6-6 fertilizer were grazed
during 3 years with beef cattle at the Range Cattle Station (5,
6, 7). Annual body weight gains per acre averaged 339 pounds
on pangolagrass and 200 pounds on Coastal bermudagrass.
In another trial at the Range Cattle Station (8, 9), pangola-
grass pastures received 90, 180 and 270 pounds of nitrogen per
acre. A complete fertilizer with a 2:1:1 ratio of N, P ,05 and
K.,O was applied in amounts to supply these levels of nitrogen.
Annual weight gains by beef cattle grazing these respective
pastures averaged 301, 462 and 626 pounds during 2 grazing
seasons. Average daily gains on these pastures were 1.3, 1.4
and 1.4 pounds, respectively.

WHITECLOVER-PANGOLAGRASS PASTURE
PROCEDURE
Whiteclover-pangolagrass pasture established on Scranton
loamy fine sand was divided into 2 2-acre pastures for grazing
in 1952. Three 1-acre plots of this pasture were used in 1953.
In February 1954 2 acres of the pasture were subdivided into
3 plots and in August these 3 plots were subdivided into 6.
Prior to establishing the pasture in 1950, 2 tons per acre of
ground agricultural limestone were spread on the area. The
pH of soil samples was 6.4 in 1952, 6.2 in 1953 and 5.9 in 1954.
Superphosphate was applied each fall; muriate of potash in the
fall, winter and spring; and nitrogen topdressings were made
during the spring, summer and fall. The amounts of phosphorus,
potash and nitrogen applied per acre for each pasture season
are shown in Table 1.






Pastures for Dairy Heifers


TABLE 1.-PHOSPHORUS, POTASH AND NITROGEN APPLIED PER ACRE TO
WHITECLOVER-PANGOLAGRASS FOR EACH PASTURE YEAR.

Nutrients, Pounds per Acre __ Average Number of N
Year Topdressings per Plot
P0:- KGO N

1952 ..... 108 168 144 5
1953 ..... 90 180 190 6
1954 ..... 100 210 201 5


Grazing was started in March each year when the clover was
about 7 inches high and was continued into the fall until frost
or until forage growth was inadequate to justify pasturing the
heifers. Plots were grazed rotationally and heifers were kept
on the pasture continuously except when removed for weighing.
Grass was grazed when length of shoots averaged about 6 inches
in 1952 and 5 inches the following 2 years. Body weights were
taken on 3 consecutive days at the beginning, the end and at
28-day intervals during the experiment. The number of ani-
mals grazing the pasture was adjusted in accordance with the
available supply and anticipated growth of forage. Shade,
drinking water, salt, steamed bonemeal and an iron-copper-cobalt
mineral mixture were provided in each plot.
Pastures were mowed when needed to cut clumps of forage
that had been grazed inadequately and to control weeds. Cattle
droppings were scattered following most rotations in order to
minimize forage refusal in areas of heavy manure accumulation.
Clover and pangolagrass forage samples comparable to the
plant portions consumed by the heifers were taken periodically
in 1953. Moisture and crude protein (N x 6.25) analyses were
made on these samples by A. O. A. C. methods (3).
Whiteclover was the principal forage in the pasture from the
beginning of each grazing season through May. As clover
growth declined in May, grass spread to cover the ground com-
pletely and then began a dense upward growth. By early June
pangolagrass was the primary forage and clover was contribut-
ing a very small amount of forage by the middle of the month.
Since the different periods of forage predominance were well
defined, the period from initiation of grazing through May is
referred to as the clover grazing season, and that from June 1
to discontinuation of grazing as the grass season.












TABLE 2.-VALUE OF WHITECLOVER-PANGOLAGRASS PASTURE FOR DAIRY HEIFERS, BY YEARS AND THE AVERAGE FOR 3 YEARS.


Clover Grazing Season
Year


Beginning of grazing seasons ....
End of grazing seasons .............
Number of rotations ...... ............


Av. gain per acre, Ib. ....................
Av. daily gain per animal, lb. ..
Gains expressed as percentage of
normal growth rate* ..............


T. D. N. obtained from pasture
per acre, b. ................................
Alfalfa hay equivalent of clover
forage per acre, tons .............
Grass hay equivalent of grass
fo, age per acre. tons ...............
Calculated feed replacement
value of forage, per acre ........


1952

3-11
5-31
2


1953

3-6
5-31
2


1954

3-3
5-31
2


238 310 322
1.3 1.3 1.5

154 152 170



1,645 2,236 2,155

1.63 2.22 2.1


$81.00 $110.00 $102.00


Average
for
3 Years


3-7
5-31
2


19


Grass Grazing Season
Year

52 1953 19


6


6-1
10-29
8


290 387 371
1.4 0.6 0.6

160 72 81


54

-1


579
0.9

102


Aver
fo
3 Ye


6-
11-
10


44


9


2,012 5,108 4,262 5,130 4,83

2.00

5.03 4.19 5.05

$98.00 $121.00 1 $112.00 $126.00 $12


age
r F
ars


1
3



6
0.7

0



3



4.76

0.00


*The standard growth curve for dairy heifers reported by Rasidale (Mo. Agr. Exp. Sta. Bul. 336) was used for comparison.


4







Pastures for Dairy Heifers


RESULTS

Grazing Periods and Total Digestible Nutrients Obtained per
Acre.-Grazing began from March 3 to 11 during the different
years and terminated from October 29 to November 9. Grazing
periods averaged 242 days and grazing was continuous each
season except for 2 interruptions totaling 17 days in 1954.
The calculated (1) amounts of total digestible nutrients ob-
tained from the pasture per acre during the clover grazing season
ranged from 1,645 to 2,236 pounds and averaged 2,012 pounds.
During the period of June 1 until termination of grazing when
pangolagrass was the primary source of nutrients, production
of total digestible nutrients ranged from 4,262 to 5,130 pounds
per acre and averaged 4,833 pounds per acre. Total yield per
acre for the entire pasture season averaged 6,845 pounds. Graz-
ing periods, total digestible nutrients obtained per acre and other
data from the experiment are shown for each grazing season in
Table 2.
Composition of Forage Samples.-Samples of whiteclover for-
age and of pangolagrass shoots comparable to that consumed
by the heifers were taken at about monthly intervals from
March to October, 1953. Sampling dates, dry matter, crude pro-
tein content and description of the forage samples are presented
in Table 3.
TABLE 3.--COMPOSITION OF WHITECLOVER AND PANGOLAGRASS
FORAGE SAMPLES.

Type of Date Dry Crude Protein_ Forage Sample
Forage Sampled Matter Fresh Dry Description
Forage Forage

Whiteclover 3/27 16.4 4.5 27.7 Clover 7 in. tall
Whiteclover 5/ 5 16.8 4.6 27.5 Clover 7 in. tall
Pangolagrass 6/30 15.6 3.6 22.9 Shoots av. 5 in.
Pangolagrass 7/23 15.1 3.2 21.1 Shoots av. 4 in.
Pangolagrass 8/22 15.4 3.3 21.6 Shoots av. 5 in.
Pangolagrass 10/ 5 16.6 3.1 18.5 Shoots av. 5 in.

Crude protein and dry matter content of whiteclover samples
were similar to those reported by Morrison (12). Pangolagrass
samples were low in dry matter, containing from 15.1 to 16.6
percent, and relatively high in crude protein, containing from






Florida Agricultural Experiment Stations


3.1 to 3.6 percent. The pangolagrass was more succulent and
higher in crude protein content than values reported for crab-
grass (12), which is similar to pangola.
Distribution of Feed Supply and Carrying Capacity of the
Pasture.-The distribution of total digestible nutrients obtained
from the pasture was more uniform during the clover grazing
periods of March, April and May than during subsequent grass
seasons. After the clover season the level of total digestible
nutrients increased and was highest during summer months of
lush grass growth. This was followed by a decline in the amount
of feed provided by the pasture in the fall as days became shorter
and weather cooler.
The amount of feed supplied by the pasture also was affected
by soil moisture. Surface water frequently stood on low areas
of the poorly drained soil during periods of heavy rainfall in
August 1953. This condition was accompanied by a decline in
the amount of total digestible nutrients obtained from pangola-
grass. Dry weather caused 2 brief interruptions of grazing in
1954 and affected forage growth adversely at times during the
other years. Total digestible nutrients obtained from the pas-
ture biweekly per acre and total rainfall for 3-day periods are
shown in Figure 2. The base line in this figure represents a
suggested uniform level of total digestible nutrients per acre
that one may use in calculating pasture acreage needed for the
herd.
Since the feed requirements of a herd are rather constant
throughout the year, the uniformity of supply as well as total
yield of nutrients are important factors in determining the acre-
age of pasture to grow. A study of these factors was made in
resolving a uniform level of total digestible nutrients for the
entire grazing season to suggest as a basis for calculating the
needed pasture acreage.
Under grazing management and growing conditions of 1952,
where 2 plots were used in rotation and 144 pounds of nitrogen
applied per acre, an average of 266 pounds of total digestible
nutrients per acre biweekly is suggested as a uniform level to
rely on from pasture grown under similar conditions. With
heavier nitrogen fertilization and more intensive grazing pro-
grams the following 2 years, a higher level of 325 pounds of
total digestible nutrients weekly per acre is the suggested amount
to rely on from pasture under comparable conditions. These
suggested levels are shown by the base lines in Figure 2.












TON O 954

600

400 0
200.


TDN FROM PASTURE RAINFALL
-- ASE LINE IN.
RAINFALL



42
I 2


Fig. 2. --Total digestible nutrients obtained bi-weekly per acre from whiteclover-panagolaglrass pasture. Rainfall is
shown by 3-day periods.


--


.






Florida Agricultural Experiment Stations


Using this basis for calculating the pasture acreage needed
by growing dairy heifers (12) reveals that an animal weighing
500 pounds would require 0.43 acre under conditions comparable
to 1952 and 0.35 acre under those of the subsequent 2 years.
For a larger heifer weighing 800 pounds, 0.56 acre would be
needed under 1952 conditions and 0.46 acre under those of the
other years.
Using total digestible nutrient level per acre shown by the
base line in Figure 2 as the amount needed for grazing purposes,
then an annual average of 4,775 pounds would have been grazed
by the heifers, and an average of 2,070 pounds of total digestible
nutrients annually would have been available above grazing
needs. Forage represented by the latter figure would have been
available for preservation and storage. During the clover graz-
ing season, 88 percent of the total digestible nutrients would
have been used for grazing purposes, while during the grass
season 62 percent of the total digestible nutrients would have
been used for this purpose.
From initiation of grazing through October 14 the level of
total digestible nutrients supplied by the pasture generally was
above that of the base line in Figure 2. After the middle of
October it was below the base line. Total digestible nutrients
supplied by the pasture fell below that of the base line an aver-
age of 17 days annually during the clover grazing season and an

Fig. 3.-Fertilized pangolagrass should be grazed when shoots are short
and forage tender for heifers to make satisfactory growth on pasture alone.



.J.A


` /'. iU






Pastures for Dairy Heifers


average of 32 days from June 1 through October 14 of the grass
season. There would have been an average deficiency of total
digestible nutrients of only 86 pounds annually during the clover
season and 181 pounds during this portion of the grass season.
Body Weight Gains.-Weight gains by heifers averaged 290
pounds annually per acre during the 76-day clover grazing sea-
sons and 446 pounds per acre for the 160-day pangolagrass graz-
ing periods. Average annual gains were 736 pounds per acre
with 39 percent of it being made during the clover season.
While the heifers were grazing clover, daily gains per animal
averaged 1.4 pounds, which was 160 percent of their normal
growth rate (13). During the grass season weight gains aver-
aged 0.7 pound daily, which was 90 percent of their normal
growth rate.
Growth was subnormal during the grass season of 1952 when
2 pasture plots were grazed in rotation and 144 pounds of nitro-
gen was applied per acre. In 1953 growth remained subnormal
during the grass season even though the number of pasture
plots was increased to 3, 190 pounds of nitrogen was applied
per acre and the rotation rate was increased. In August of
1954 the pasture was subdivided into 6 plots so that the animals
would remain on each plot for a shorter period and the grass
could be grazed in the growth stage when it was more palatable
and nutritious. This change in grazing management is believed
to be an important factor in improving the growth rate of the
heifers on grass pasture.
Hay Equivalents and Feed Replacement Value of the Pasture.
-Since whiteclover is similar in composition to alfalfa, this hay
was used as the reference roughage in evaluating the feed ob-
tained from the pasture during the clover grazing season. Pub-
lished information on the nutritive value of pangolagrass hay
has not been observed and that for well-fertilized Coastal ber-
mudagrass hay is believed to be most comparable to the value
of the pangolagrass pasture. Total digestible nutrients equiva-
lent to that in 2 tons of alfalfa hay were obtained per acre an-
nually from the pasture during the clover season. Total digestible
nutrients contained in the forage grazed annually during the
grass seasons were equivalent to that in 4.76 tons of Coastal
bermudagrass hay.
In calculating the feed replacement value of the pasture,
consideration was given to the fact that the roughage require-
ment of a herd is rather constant under practical management.






Florida A,;' i;,l -tral Experiment Stations


Therefore the total digestible nutrient level represented by the
base line in Figure 2 was used as the amount needed from the
pasture by the herd. The quantity above this line was con-
sidered as surplus which could be converted into stored rough-
age. The alfalfa hay equivalent of clover forage that could be
utilized as grazed forage was valued at $52 per ton and the hay
equivalent of the excess forage at $26 per ton. The Coastal ber-
mudagrass hay equivalent of the pangolagrass forage that could
be grazed was valued at $31 per ton and the excess at $15.50
per ton.
The annual feed replacement value per acre of the pasture
averaged $98 during the clover grazing season and $119 during
the grass grazing season, or $217 per year.
Calculated Production Costs and Net Returns.-Production
costs of the pastures were calculated by using prevailing prices
for fertilizers and land rent. Cultural practices were assessed
according to charges made for local custom work when pastures
are 10 acres or larger. Land rent was $8 per acre and the cost
of $15 per acre for sprigging grass and seeding clover was
amortized over a 10-year period. Fertilizer costs per ton were:
ground limestone, applied, $5; 18 percent superphosphate, $22;
20 percent superphosphate, $24; muriate of potash (60 percent
KO), $54; and ammonium nitrate, $85. Assessments for cul-
tural practices per acre were: spreading superphosphate, $1.50;
applying muriate of potash, $1.35; topdressing with nitrogen,
$1.35; mowing, $1.35; scattering droppings, $1.25; mowing and
scattering droppings, combined, $1.45; and raking grass, $1.35.
Calculated production cost of the pasture averaged $74 per
year. Production cost of total digestible nutrients obtained from
the pasture averaged 1.08 cents per pound. The calculated aver-
age annual feed replacement value of the pasture was $217 and
the net return $143 per acre.

WHITECLOVER-COASTAL BURMUDAGRASS PASTURE
PROCEDURE
Whiteclover-Coastal bermudgrass pastures were established
on Scranton loamy fine sand adjacent to the experimental white-
clover-pangolagrass pastures. Fertilization and grazing-man-
agement practices in 1952 and 1954 were as described for
whiteclover-pangolagrass during the respective years except the
bermudagrass shoots averaged about 7 inches in length when






Pastures for Dairb I Heifes


grazed in 1952. These practices during 1953 were comparable
to that of the clover-pangolagrass pastures on the 2 acres of
clover-bermudagrass pasture that were grazed experimentally
in 1954 and 1955. However, in 1953 1 of the 3 plots grazed was
not considered comparable to the other 2 nor to clover-pangola-
grass plots and grazing data for this year are not presented.
In 1955 the 2 acres of whiteclover-Coastal bermudagrass pasture
were grazed rotationally by narrow strips using electric fences
(11). One hundred pounds of P0-,, 180 pounds of K20, and
251 pounds of N were applied per acre during the pasture season.
Forage samples were taken in July, August, September and
October, 1953, from the 2 1-acre plots of pasture that were
comparable to the 2 plots of pangolagrass sampled. Moisture
and crude protein (N x 6.25) analyses were made on these sam-
ples by A. O. A. C. methods (3).

RESULTS
Grazing Periods and Total Digestible Nutrients Obtained per
Acre.-The average date grazing began during the 3 years was
March 5, and the average termination date was November 4.
Grazing season averaged 246 days and grazing was continuous
during the first 2 years, but was interrupted by dry weather
for an 11-day period in 1955.
From initiation of grazing through May, when clover was
the primary forage, the amount of total digestible nutrients ob-
tained from the pasture ranged from 1,218 to 2,759 pounds and
averaged 1,833 pounds for the 3 years. During the period of
June 1 to termination of grazing, when bermudagrass was the
principal forage, total digestible nutrients supplied by the pas-
ture ranged from 3,839 to 4,332 pounds and averaged 4,108
pounds. An average of 5,941 pounds of total digestible nutrients
was obtained from the pasture per year. Grazing periods and
total digestible nutrients obtained from the whiteclover-Coastal
bermudagrass pasture per acre are shown in Table 4.
Composition of Forage Samples.-Samples of Coastal ber-
mudagrass forage comparable to that consumed by the heifers
were taken at about monthly intervals from early July to Octo-
ber, 1953. The crude protein content of 4.5 to 5.7 percent is
higher than that reported for fertilized Coastal bermudagrass
by Morrison (12). Sampling dates, dry matter, crude protein
content and description of the forage samples are shown in
Table 5.











TABLE 4.-VALUE OF WHITECLOVER-COASTAL BERMUDAGRASS PASTURE FOR DAIRY HEIFERS BY YEARS AND THE AVERAGE
FOR 3 YEARS.


Clover Grazing Season
Year


1952 1954


1955


Average
for
3 Years


Grass Grazing Season
Year


Average
for
3 Years
- a


Beginning of grazing seasons ..
End of grazing seasons ........
Number of rotations ..............


Av. gain per acre, Ib. ............
Av. daily gain per animal, lb.
Gaines expressed as percentage
of normal growth rate ....


T. D. N. obtained from pasture
per acre, lb......... .. .........
Alfalfa hay equivalent of forage
predominantly clover per acre,
ton s ..... .............
Grass hay equivalent of forage
predominantly grass per acre,
ton s ..................... .......
Calculated feed replacement
value of forage, per acre ......


2-24 3-9
5-31 5-31
2 2


223 395 197
1.3 1.4 1.6


3-5 6-1 6-1 6-1 6-1
5-31 11-5 11-1 11-5 11-4
2 7 6 6 6


272 211 411 518 380
1.4 0.3 0.9 1.0 0.8


141 177 177 167 44 109 108 96



1,521 2,759 1,218 1,833 4,332 3,839 4,154 4,108


4.26
$76.00 $123.00 $61.00 $87.00 $108.00


3.78

$105.00


4.09

$110.00


4.04

$108.00


The standard growth curve for dairy heifers reported by Razsdale IMo. Agr. Exp. Sta. Bul. 336) was used for comparison.






Pastures for Dair.i Heifers


TABLE 5.-COMPOSITION OF COASTAL BERMUDAGRASS FORAGE SAMPLES.

Type of Date Dry Crude Protein Forage Sample
Forage Sampled Matter Fresh Dry Description
Forage Forage


Coastal
bermudagrass 7/ 6 31.0 5.0 16.2 Shoots av. 5 in.
Coastal
bermudagrass 8/12 28.4 4.6 16.2 Shoots av. 5 in.
Coastal
bermudagrass 9/ 3 27.8 4.5 16.2 Shoots av. 5 in.
Coastal
bermudagrass 10/ 3 31.4 5.7 18.1 Shoots av. 5 in.


Distribution of Feed Supply and Carrying Capacity of the
Pasture.-The level of total digestible nutrients obtained from
the pasture in 1952 was uniform and rather low during the
clover season but was high during the summer period of the
grass season. Lush clover growth early in the 1954 grazing sea-
son was favored by heavy rainfall totalling 56 inches during the
9-month period preceding initiation of grazing. However, rain-
fall totalled only 6 inches during the grazing season and low
soil moisture retarded growth of clover in May and of grass in
early June.
Dry weather through June 22, 1955, caused a low feed yield
by clover through May and by grass through June. The high
yield peak attained in July apparently was influenced by usage
made of accumulated plant food when the soil moisture became
adequate. The total digestible nutrients obtained from the pas-
ture biweekly per acre and total rainfall for 3-day periods are
shown in Figure 4. The base line represents a suggested uni-
form level of total digestible nutrients per acre that may be
used in determining needed pasture acreage.
Under growing and grazing management conditions of 1952,
266 pounds of total digestible nutrients biweekly per acre is
the suggested level to rely on for grazing purpose from pasture
under similar conditions. A higher level of 325 pounds of total
digestible nutrients biweekly per acre is the suggested level to
rely on from pastures under the more intensive grazing manage-
ment and fertilization programs employed in 1954 and 1955.
Using these levels as the amounts needed for grazing, an average




























1952



44, - - -- ^ -- T- -+- -y

PEhRUARY MARCH APRtL MAY JUNE JULY AUUST SEPTEMBER OCTOBER NOVEMBER
CLOVER SEASON GRASS SEASON
MONTHS
Fig. 4.-Total digestible nutrients obtained bi-weekly per acre from whiteclover-coastal bermudagrass pasture. Rainfall is
shown by 3-day periods.







Pastures for Dairy Heifers


of 4,485 pounds of total digestible nutrients would have been
utilized annually for this purpose and forage representing an
average 1,456 pounds of total digestible nutrients would have
been available for other purposes such as hay production. An
average of 84 percent of the total digestible nutrients produced
during the clover grazing season and 72 percent of that obtained
during the grass season would have been utilized for grazing
purpose.
The level of total digestible nutrients supplied by the pasture
generally was above that represented by the base line in Figure 2
during 1952 and 1954, but was below 111 days in 1955. The
total digestible nutrients furnished by the pasture fell below
the base line an average of 34 days during the clover grazing
season and an average of 39 days through October 14 of the
grass season. The pasture would have been deficient an average
of 374 pounds of total digestible nutrients annually during the
clover season and 333 pounds through October 14 of the grass
season.
Body Weight Gains.-Annual weight gains by the heifers
averaged 652 pounds per acre. During the 90-day clover graz-
ing season, gains averaged 272 pounds per acre, and for the
157-day grass season they averaged 380 pounds per acre. Forty-
two percent of the total gain was made while grazing clover.

Fig. 5.-When Coastal bermudagrass was grazed intensively and fertilized
liberally, heifers made satisfactory growth on pasture alone.






Florida Agricultural Experiment Stations


During the clover grazing season, daily gain per heifer aver-
aged 1.4 pounds, which was 167 percent of their normal growth
rate (13). Gains averaged only 0.3 pound daily per animal, or
44 percent of their normal growth rate, during the grass season
of 1952. Daily gains averaged 0.9 pound, which was 109 percent
of the normal growth rate, during the grass season of 1954.
Subdivision of the 3 plots into 6 in August to increase pasture
rotation rate and raising the nitrogen fertilization to 190 pounds
per acre contributed to this higher gain rate. Rotational grazing
by narrow strips (11) was responsible primarily for a further
increase in gain rate to 1.0 pound daily in 1955. Improvements
in grazing management and fertilization rates were accompanied
by higher total gains per acre during the grass season.
Hay Equivalents and Feed Replacement Value of the Pasture.
-The average amount of total digestible nutrients per acre ob-
tained from the pasture during the clover grazing seasons was
equivalent to that in 1.82 tons of alfalfa hay. The amount ob-
tained from the forage grazed during the grass season was
equivalent to the total digestible nutrients in 4.04 tons of fertil-
ized Coastal bermudagrass hay.
Feed replacement value of the pasture was calculated accord-
ing to the procedure described for whiteclover-pangolagrass pas-
ture. The annual feed replacement value of the pasture per acre
averaged $87 during the clover season and $108 during the grass
season, or $195 per year.
Calculated Production Costs and Net Returns.-Pasture pro-
duction cost and net returns were calculated by the methods
described for whiteclover-pangolagrass pasture. The average
annual cost of producing the pasture was calculated to be $75
per acre. The annual feed replacement value of the pasture was
$195 and the net return $120 per acre. Average production cost
per pound of total digestible nutrients obtained from the pasture
was calculated to be 1.08 cents.

GENERAL DISCUSSION
The length of grazing season was about the same for the
2 pastures during 1952 and 1954 when they were compared. Two
rotations were made during the clover season each year. Eight
rotations were made on pangolagrass each of these years, as
compared with 7 on bermudagrass in 1952 and 6 in 1954.
Total digestible nutrients obtained annually per acre from
the pastures in 1952 and 1954 averaged 7,019 pounds for white-







Pastures for Dairy Heifers


clover-pangolagrass and 6,225 pounds for whiteclover-Coastal
bermudagrass. An average of 1,033 pounds more total digestible
nutrients was obtained from pangola during the grass grazing
seasons than from Coastal bermuda. Pangolagrass appeared to
grow more rapidly than did the Coastal bermuda. This observa-
tion is supported by the greater number of rotations and larger
yield of total digestible nutrients obtained.
Gain in body weight per acre in 1952 averaged 625 pounds
on whiteclover-pangolagrass and only 434 pounds on whiteclover-
Coastal bermudagrass. This difference in gain was due to slower
growth made by heifers on the coarser bermudagrass and a lower
yield of total digestible nutrients by this pasture during the
grass season. In 1954, the daily gain rate averaged 0.9 pound
for heifers on each pasture during the grass season. The ani-
mals gained an average of 901 pounds on clover-pangola pasture
and 806 pounds on clover-berumudagrass. This larger gain on
clover-pangolagrass was due primarily to the higher yield of
total digestible nutrients by this pasture.
During the grass season of 1952, the animals remained on
each plot for rather long periods (10 or more days) and the
grass, particularly Coastal bermuda, became somewhat coarse.
Increase in coarseness was accompanied by decline in quality and
the heifers made poor gains during this grass season. In 1953
the whiteclover-pangolagrass pasture was divided into 3 plots
and the rotations were increased to 13 during the grass season.
The animals were not on each plot long enough to graze the
forage closely, and some coarse shoots developed. Average daily
gains during the grass season remained at 0.6 pound.
After each pasture was subdivided into 6 plots in 1954, the
forage in each area could be grazed down in a short period during
the growth stage while it was tender, palatable and nutritious.
Average daily gain during the grass season was 0.9 pound on
each pasture. Using an electric fence to expose new strips of
bermudagrass forage to the animals twice daily in 1955 was
accompanied by an increase in average gain to 1.0 pound daily.
Quality of forage probably was influenced also by the levels of
nitrogen fertilization employed. The amounts of nitrogen applied
per acre were 144 pounds in 1952, 190 in 1953, 201 in 1954, and
251 pounds in 1955.
Growth rate of the animals probably was limited by intake
of energy. The ratio of dry matter to the crude or digestible
protein calculated on the basis of the 1953 Coastal bermudagrass






Florida Agricultural Experiment Stations


samples analyzed was narrower than that recommended for
growing dairy heifers by Morrison (12). The crude protein con-
tent of pangolagrass samples was higher than that of bermuda-
grass samples on the dry matter basis. Therefore, the ratio of
dry matter to digestible crude protein in pangolagrass was nar-
rower than that recommended for growing heifers.
Improvement in quality of pangola forage increased weight
gains during the grass season from 387 pounds per acre in
1952 to 579 pounds in 1954, even though the amounts of total
digestible nutrients obtained from the pasture were almost
identical for the 2 years. Body weight gains on Coastal bermuda-
grass rose from 211 pounds in 1952 to 518 in 1955, although
278 pounds less of total digestible nutrients were obtained per
acre during the latter grass season. Forty percent of the total
gains were made during the clover grazing seasons, while this
forage supplied only 30 percent of the total digestible nutrient
intake.
SUMMARY AND CONCLUSIONS
Whiteclover-pangolagrass and whiteclover-Coastal bermuda-
grass pastures grown on Scranton loamy fine sand were grazed
intensively with separate groups of dairy heifers for 3 years.
Whiteclover was the principal forage each year from beginning
of grazing through May and grass supplied practically all of the
forage after June 1.
A comparison between the pastures was made during 2 years.
Total digestible nutrients obtained per acre from the pastures
during the 2 years averaged 7,019 pounds for whiteclover-pan-
golagrass and 6,255 pounds for whiteclover-Coastal bermuda-
grass. Most of this difference in yield occurred during the grass
grazing season.
Body weight gains per acre in 1952 averaged 625 pounds on
whiteclover-pangolagrass and 434 pounds on whiteclover-Coastal
bermudagrass. Most of this difference occurred during the grass
grazing season and was due to the lower total digestible nutrient
yield and slower growth made by the bermudagrass. The higher
gain per acre in 1954 of 901 pounds by the animals on clover-
pangolagrass as compared to 806 pounds by those on clover
bermudagrass was due principally to the larger yield of total
digestible nutrients obtained from the clover-pangolagrass pas-
ture. Growth rates the latter year were the same on both
pastures.







Pastures for Dairy Heifers


Mean daily gains of 1.4 pounds made by heifers on the pas-
tures during the clover grazing season were 163 percent of their
normal growth rate. Subnormal growth was made during the
grass seasons when only 2 plots were grazed rotationally in
1952 and 3 were grazed rotationally in 1953. Subdivision of
each pasture into 6 plots in August 1954 and employment of the
strip grazing technique on the whiteclover-bermudagrass pas-
ture in 1955 was accompanied by gains slightly above normal
during these grass seasons. Lack of energy appeared to be the
factor limiting growth.
As growth rate of the heifers increased, the amount of total
digestible nutrients required to produce a pound gain in weight
decreased. An average of 6.8 pounds of total digestible nutrients
was consumed per pound increase in body weight while the ani-
mals were gaining 1.4 pounds daily on whiteclover. The pounds
of total digestible nutrients consumed per pound of gain made
during the grass seasons ranged from 20.5 on bermudagrass in
1952 when daily gains averaged 0.3 pound to 7.8 pounds of total
digestible nutrients in 1955 when gains averaged 1.0 pound
daily. Gain in body weight per acre of pasture grazed is de-
pendent upon quality of forage as well as the amount of total
digestible nutrients produced.
Gains above the normal growth rate were made on grass
where grazing was begun when shoots averaged about 5 inches
in length and each new area was grazed down in 3 days or less.
Since increase in shoot length is accompanied by decrease in
forage quality, these grasses would be less adaptable to a field
chopping program if a quality forage is desired.

ACKNOWLEDGMENT
Appreciation is expressed to Hermon L. Somers for his assistance with
management of cattle and pastures during 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. Jour. 44: 39-50. 1952.
2. Anon. Findings in Farm Science. Wis. Agr. Exp. Sta. Bul. 438:
45-46. 1937.
3. Association of Official Agricultural Chemists. Official and tentative
methods of analysis. 7th ed. 1950.







Florida Agricultural Experiment Stations


4. CRAFT, W. D., J. R. OWEN, W. C. COWSERT and J. T. MILES. A John-
songrass-sorghum hybrid, Coastal bermudagrass and Tift sudan for
milk production. Proc. Assoc. Sou. Agr. Workers 55th Ann. Con-
vention: 104-5. 1958.

5. Fla. Agr. Exp. Sta. Ann. Rept. 1953: 308-9.

6. Fla. Agr. Exp. Sta. Ann. Rept. 1954: 278.

7. Fla. Agr. Exp. Sta. Ann. Rept. 1955: 300.

8. Fla. Agr. Exp. Sta. Ann. Rept. 1956: 291-92.

9. Fla. Agr. Exp. Sta. Ann Rept 1957: 332.

10. JOHNSON, J. C., JR., G. J. JONES and B. L. SOUTHWELL. High and low
nitrogen applications on Coastal bermudagrass as it effects milk
production. Proc. Assoc. Sou. Agr. Workers 50th Ann. Convention:
83-4. 1953.

11. MITCHELL, W. G. "Ribbon grazing" brings more milk. Prog. Farmer.
(Ga.-Ala.-Fla. Ed.) 70 (9): 28. 1955.

12. MORRISON, F. B. Feeds and Feeding. 22nd ed. The Morrison Pub-
lishing Co. 1957.

13. RAGSDALE, A. C. Growth standards for dairy cattle. Mo. Agr. Exp.
Sta. Bul. 336. 1934.

14. S. C. Agr. Exp. Sta. 69th Ann. Rept.: 37. 1957.




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