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Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 695
Title: Productivity of beef cows as influenced by pasture and winter supplement during growth
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Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00027095/00001
 Material Information
Title: Productivity of beef cows as influenced by pasture and winter supplement during growth
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 15 p. : ; 23 cm.
Language: English
Creator: Warnick, A. C ( Alvin C )
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1965
 Subjects
Subject: Heifers -- Feeding and feeds   ( lcsh )
Heifers -- Growth   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 15.
Statement of Responsibility: A.C. Warnick.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027095
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000929281
oclc - 18361517
notis - AEP0059

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AGRICULTURAL EXPERIMENT STATIONS
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA, GAINESVILLE
J. R. BECKENBACH, DIRECTOR












CONTENTS

Page

Introduction and Review of Literature_ ---_-- 3
Materials and Methods .. ---.---- -- 3
Pasture Management ..- ----- ----- ------- 4
Cattle Management .------------------- 5
Statistical Analysis .9.....--------- --------- 9
Results and Discussion .. ....----- 9
Reproduction ------------ 11
Weaning Data ..------ --------- 13
Summary ------------------------------- 13
Literature Cited ...--------------------- 15







PRODUCTIVITY OF BEEF COWS AS

INFLUENCED BY PASTURE AND WINTER
SUPPLEMENT DURING GROWTH

A. C. Warnick, M. Koger, A. Martinez, and T. J. Cunha1


INTRODUCTION AND REVIEW OF LITERATURE
The weight of many commercial beef heifers in Florida when
bred for the first time at two years of age is 100 to 200 pounds
less than the 800 pounds recommended by beef cattle specialists
(5)2. It is possible that the method of growing replacement
heifers will influence their subsequent production as they en-
ter the breeding herd. Nelson et al. (6) found in Oklahoma that
winter and yearly gains in beef heifers were proportional to
level of protein supplement given during the winter. Previous
research at the Beef Research Unit near Gainesville, Florida,
has shown 20 percent more calves at weaning in cows grazed on
clover-grass compared to those grazed on complete grass pas-
tures (4).
An experiment was designed to provide data on methods for
developing replacement heifers. Replacement heifers were
grown to two years of age on two types of pasture and on two
levels of protein supplementation during the winter months,
and the effects were determined on subsequent reproductive
rate and weaning weight of calves.

MATERIALS AND METHODS
The data used in this study were obtained at the Beef Re-
search Unit of the Florida Agricultural Experiment Station near
Gainesville3. Included in the data were records from all replace-

SWarnick: Animal Physiologist, Animal Science Department, Main
Station.
Koger: Animal Geneticist, Animal Science Department.
Martinez: Former Graduate Assistant. Present address: Animal Pro-
duction Department, Central University of Venezuela, Maracay, Venezuela.
Cunha: Animal Nutitionist and Head, Animal Science Department.
2 Numbers in parentheses refer to Literature Cited.
SAcknowledgement is made to the Coordinating Committee of the Beef
Research Unit for permission to use animals and facilities for this study.







Florida Agricultural Experiment Stations


ment heifers born at the Beef Research Unit from 1953 to 1956
from dams of approximately 1' Brahman and 1/, Native breeding
mated to Angus, Brahman, Hereford, or Shorthorn bulls. In-
cluded also were a few Angus x Hereford heifers purchased at
weaning time. The reproduction data include records of all
heifers and cows that entered the breeding herds. The produc-
tion data include records only from cows that weaned one or
more calves.


Pasture Management

The heifers were grazed year-around on two types of pas-
tures: 1) all-grass pasture which consisted of pangolagrass
(Digitaria decumbens) and Pensacola bahiagrass (Paspalum
notatum) and 2) clover-grass pasture which included pangola-
grass and Pensacola bahiagrass overplanted with Nolin's Louisi-
ana white clover (Trifollum repens).
The two grass species were planted in separate fenced pas-
tures and heifers were rotated between the different pastures.
It was not possible to separate the contribution of the two spe-
cies of grasses, but the same grass species were in both the
all-grass and clover-grass pastures. During the winter the
grasses were frosted and dormant, and heifers grazed the re-
serve frosted grass. There was variable growth of clover in
the clover-grass pastures during this period, depending on
temperature and moisture. Forage production started earlier
in the spring on the clover-grass pastures than on the all-grass
pastures because of earlier growth of clover. Chemical analyses
of forage from the grass pastures from February to September
showed an average protein content of 7.1 percent, while forage
from clover-grass pastures averaged 12.3 percent (4). The
average protein content of forage during the winter months
from the grass pastures was 2.52 percent, while forage from
clover-grass pastures averaged 9.14 percent.
Grass pastures received a total of 225 pounds of an 8-8-8
fertilizer mixture and 50 pounds of ammonium nitrate annually.
One-half of the area received the 8-8-8 fertilizer in the spring
and ammonium nitrate in late summer. The remaining half
received the ammonium nitrate in the spring and 8-8-8 in late
summer. Clover-grass pastures received a total of 600 pounds
of 0-12-12 fertilizer applied in October.







Productivity of Beef Cows


Cottle Management
The heifers born in 1953, 1954, and 1955 were divided into
four groups when feed supplementation began during their first
winter, and retained there until they entered the breeding herd
at two years of age (Tables 1, 2, and 3). Two of these groups
were maintained on grass pasture and the other two groups on
clover-grass pasture. During the winter months, one of the
groups of heifers on each of the two types of pasture regime was
supplemented with up to 2.5 pounds of protein supplement, while
the other group received minimum requirements (1.0 pound
maximum) or no protein supplement. Heifers fed the highest
level of protein supplement also were fed for a longer period.
Small amounts of energy feed were offered certain groups, as
shown in Tables 1, 2, and 3. After the end of the winter feeding
periods, the two groups on grass and the two groups on clover-
grass pastures were combined on their respective pasture until
the second winter feeding period began. Hereafter, the respec-
tive groups will be referred to as grass L.P. (low protein),
grass H.P. (high protein), clover-grass L.P., and clover-grass
H.P., depending on type of pasture and the amount of protein
supplement given.
The heifers born in 1956 were fed grass silage the first winter
and grazed clover-grass pastures until they entered the
breeding herd. All these heifers received 1 pound of 41 percent
protein cottonseed meal daily from December 1 to March 1 each
winter. One-half of these heifers received 3 pounds of corn
daily during the first winter feeding period and were classified
as clover-grass H.P., while the other received no corn and
were called clover-grass L.P.
The feed supplement was fed daily in troughs during the
morning. All animals had free access to fresh water and a salt-
mineral mixture throughout the year. All heifers were weighed
in August, November, March, and June.
After their second winter the heifers in each group were
distributed equally at random to breeding herds and all grazed
on similar type pasture. Angus, Brahman, and Hereford bulls
were used each year, and, in addition, Santa Gertrudis bulls
were used in 1958 and 1959. The breeding season began the
second of March and ended on June 1 (92 days) except that the
first breeding season for the 1953 heifers was from February 2
to June 4 in 1955. The cows grazed pastures year-around and









Table 1.-Winter Feeding Data of Heifers Born in 1953.

Pasture and Amount
Supplement No. of Days Fed Daily,
Level Heifers Supplement Fed Lbs. Period Fed Supplement


41% cottonseed
41% cottonseed


41% cottonseed
41% cottonseed


Clover-grass L.P.
Clover-grass H.P.


Grass L.P.


Grass H.P.


Clover-grass L.P.


Clover-grass H.P.


*L.P. = low protein
H.P. = high protein


10 Citrus pulp
Ground snapped

8 41% cottonseed



10 Citrus pulp
Ground snapped

9 41% cottonseed


First Winter
meal 80
meal 80
36

meal 80
meal 80
26


Second Winter
20
corn 20

meal 123
17
125

20
corn 20

meal 7
114


Nov. 17, 1953 to Feb. 4, 1954
Nov. 17, 1953 to Feb. 4, 1954
Feb. 5, 1954 to Mar. 12, 1954

Nov. 17, 1953 to Feb. 4, 1954
Nov. 17, 1953 to Feb. 4, 1954
Feb. 5, 1954 to Mar. 2, 1954



Feb. 10, 1955 to Mar. 1, 1955
Feb. 10, 1955 to Mar. 1, 1955

July 1, 1954 to Oct. 31, 1954
Nov. 1, 1954 to Nov. 17, 1954
Nov. 18, 1954 to Mar. 22, 1955

Feb. 10, 1955 to Mar. 1, 1955
Feb. 10, 1955 to Mar. 1, 1955

Nov. 11, 1954 to Nov. 17, 1954
Nov. 18, 1954 to Mar. 22, 1955


Grass L.P.*
Grass H.P.








Table 2.-Winter Feeding Data of Heifers Born in 1954.

Pasture and Amount
Supplement No. of Days Fed Daily,
Level Heifers Supplement Fed Lbs. Period Fed Supplement


Grass L.P.*

Grass H.P.


Clover-grass L.P.

Clover-grass H.P.


First Winter
9 Citrus pulp 91
Ground corn 91
10 41% cottonseed meal 61
17
125
8 Citrus pulp 70
Ground corn 70
9 41% cottonseed meal 61


Dec. 22, 1954 to Mar. 22, 1955
Dec. 22, 1954 to Mar. 22, 1955
Sept. 1, 1954 to Oct. 31, 1954
Nov. 1, 1954 to Nov. 17, 1954
Nov. 18, 1954 to Mar. 22, 1955
Dec. 22, 1954 to Mar. 1, 1955
Dec. 22, 1954 to Mar. 1, 1955
Sept. 1, 1954 to Oct. 31, 1954
Nov. 1, 1954 to Nov. 17, 1954
Nov. 18, 1954 to Mar. 1, 1955


Second Winter


Grass L.P.


Grass H.P.




Clover-grass L.P.
Clover-grass H.P.


8 Ground snapped corn
Citrus pulp
Molasses
6 41% cottonseed meal
41% cottonseed meal
Citrus pulp
Ground snapped corn
Molasses
7 None
7 41% cottonseed meal


26 1.0
26 1.0
26 1.0
121 1.0
26 2.0
26 1.0
26 1.0
26 1.0
0 0
127 1.0


Feb. 4,
Feb. 4,
Feb. 4,
Oct. 6,
Feb. 4,
Feb. 4,
Feb. 4,
Feb. 4,


Feb. 29, 1956
Feb. 29, 1956
Feb. 29, 1956
Feb. 3, 1956
Feb. 29, 1956
Feb. 29, 1956
Feb. 29, 1956
Feb. 29, 1956


Oct. 6, 1955 to Feb. 9, 1956


*L.P. = low protein
H.P. = high protein










Table 3.-Winter Feeding Data of Heifers Born in 1955.

Pasture and Amount
Supplement No. of Days Fed Daily,
Level Heifers Supplement Fed Lbs. Period Fed Supplement

First Winter
Grass L.P.* 8 Ground snapped corn 39 1 Feb. 4, 1956 to Mar. 13, 1956
Citrus pulp 39 1 Feb. 4, 1956 to Mar. 13, 1956
Molasses 39 1 Feb. 4, 1956 to Mar. 13, 1956
Grass H.P. 8 41% cottonseed meal 121 1 Oct. 6, 1955 to Feb. 3, 1956
41% cottonseed meal 39 2 Feb. 4, 1956 to Mar. 13, 1956
Citrus pulp 39 1 Feb. 4, 1956 to Mar. 13, 1956
Molasses 39 1 Feb. 4, 1956 to Mar. 13, 1956
Ground snapped corn 39 1 Feb. 4, 1956 to Mar. 13, 1956
Clover-grass L.P. 8 None 0 0
Clover-grass H.P. 8 41% cottonseed meal 127 1 Oct. 6, 1955 to Feb. 9, 1956
Second Winter
Grass L.P. 5 None 0 0
Grass H.P. 7 41% cottonseed meal 152 2 Oct. 1, 1956 to Mar. 1, 1957
Clover-grass L.P. 6 None 0 0
Clover-grass H.P. 7 41% cottonseed meal 93 1 Nov. 1, 1956 to Feb. 1, 1957

*L.P. = low protein
H.P. = high protein







Productivity of Beef Cows


received some supplemental feed during the winter if adequate
forage was not available.
Calves produced by these replacement females were grown
without creep-feed and were weighed and weaned at an average
age of 205 days on August 20. At this same time, cows were
weighed and palpated for pregnancy. All two-year-old heifers
not pregnant were culled. All three-year-old females sired by
Angus and Hereford bulls were culled the first time found
nonpregnant. In the Brahman and Shorthorn groups, a few of
the higher producing heifers were retained until nonpregnant
for the second time. Calves were graded at weaning by a com-
mittee of three people, and the average of the three slaughter
grades was used as the score for each calf.

Statistical Analysis
Data were analyzed by fitting constants for main effects only,
using the methods for disproportionate subclass numbers as
described by Anderson and Bancroft (1). The variables included
were winter programs, breed and age of cow, lactation status
during previous year, and year of record. Only the data on
winter programs are presented. The solutions of the equations
were obtained by matrix inversion utilizing the I.B.M. 650
computer.

RESULTS AND DISCUSSION
The average initial weights of heifers born in 1953, 1954, and
1955 in November at the beginning of the first winter feeding
program were approximately the same for all groups (Table 4).
At the end of the first year's wintering program in March, the
heifers on the grass L.P. program had lost an average of 7
pounds each, while those on the other three groups all had
gained weight. There was a significant effect (P<.05) of protein
level on weights of heifers in March, with those getting the high
protein level being 36 pounds heavier than those on low protein.
Although the heifers on the clover-grass pastures were 14 pounds
heavier than those on all grass, these differences were not sta-
tistically significant. In August the two grass groups weighed an
average of 63 pounds less than the two clover-grass groups.
The average weight of the heifers on the high protein supple-
mentation on both types of pasture was 32 pounds heavier than
those on the low protein supplementation.

















Table 4.-Average Weights of Heifers During Their First and Second Year of Growth.


Pasture and
Level of
Supplementation


No. Heifers
at End
Expt.


First
Nov. Mar.
lbs. lbs.


Year
June
lbs.


Second Year
Nov. Mar. June Aug.
lbs. lbs. lbs. lbs.


Grass L.P.* 21 420 413 501 572 640 584 700 782
Grass H.P. 19 420 454 526 593 690 663 749 818
Clover-grass L.P. 21 421 433 545 624 680 665 817 881
Clover-grass H.P. 20 424 463 586 667 729 692 865 926
PASTURE:
Grass 40 420 434 514 583 665 624 725 800
Clover-grass 41 423 448 566 646 705 679 841 904
Level of probability N.S. -- .01 -- .01
LEVEL OF
SUPPLEMENTATION:
L.P. 42 421 423 523 598 660 625 759 832
H.P. 39 422 459 551 630 710 678 807 872
Level of probability .05 -.01 N.S.

*L.P. = low protein
H.P. = high protein


----







Productivity of Beef Cows


During the second year of growth, similar trends due to
pasture and protein supplementation were observed. The heifers
on the clover-grass pastures were 55 pounds heavier than those
on all-grass pastures in March at the end of the wintering period.
Also, heifers receiving the high protein supplement were 53
pounds heavier than those on low protein in March. The weight
differences due to pasture and level of protein supplement were
both statistically significant at the 1 percent probability level.
The average weights when the heifers were approximately 30
months of age (August) showed that the heifers on the two
clover-grass groups were 104 pounds heavier than those on the
straight grass pastures. Heifers that had received the high pro-
tein supplement on both types of pasture were 40 pounds heavier
than the low protein groups. These differences in weight due
to type of pasture were significant (P<0.01), while differences
between the levels of protein were not statistically significant.
This same trend of heavier weights in heifers on better nutrition
has been observed by others at Oklahoma and Nevada (2, 6, 7).

Reproduction
Effects of Winter Program.-The heifers born in the years
1953 through 1956 were mated during five, four, three and two
breeding seasons, respectively, and the data on calving and wean-
ing were based on 295 cow breeding exposures. The different
winter programs studied had a significant effect (P<0.05) upon
percentage of calves born but showed no significant effect on
percentage weaned. The percentage of calves born was approxi-
mately 15 percent greater in the females raised on the clover-
grass pasture groups compared to those from grass pastures
(Table 5). The heifers raised on the clover-grass pasture H.P.
had a calving rate of 96 percent, compared with 95 percent for
the clover-grass L.P. heifers, 82 percent for the grass H.P., and
80 percent for the grass L.P. group. The heifers raised on high
protein had only 1 percent more calves than those raised on low
protein. Thus, type of pasture which the heifers were grown
on had a greater effect on subsequent reproduction than level
of protein supplement given during the winter. These data are
similar to that from cows grazing clover-grass pastures that
weaned 20 percent more calves than similar type cows on all-
grass pastures (7).
It was possible that the better year-around distribution of












Table 5.-Effects of Growing Heifers on Different Types of Pasture and Levels of Protein Supplement on Subsequent Production.


Pasture and Age of Daily Wt. of Cows
Level of No. of Calving Weaning Calves, Gain, Slaughter that Weaned
Supplementation Cows %* %* Days* Lbs.* Grade* Calves, Lbs.*

Grass L.P.t 63 80 74 216 1.75 9.2T 882
Grass H.P. 49 82 77 226 1.75 9.7 903
Clover-grass L.P. 89 95 86 225 1.74 9.1 921
Clover-grass H.P. 94 96 91 221 1.80 9.3 958
PASTURE
Grass 112 81 76 221 1.75 9.5 893
Clover-grass 183 96 89 223 1.77 9.2 940
Level of probability .05 .05 N.S N.S N.S .01
LEVEL OF SUPPLEMENTATION
L.P. 152 88 80 221 1.75 9.2 902
H.P. 143 89 84 224 1.77 9.5 931
Level of probability N.S. N.S. N.S. N.S. N.S. N.S.
TOTAL COWS AND
OVERALL MEAN 295 88 82 222 1.76 9.3 916

*Means from least square analysis
tL.P. = low protein
H.P. = high protein
$8 = high commercial, 9 = low good, and 10 = medium good







Productivity of Beef Cows


grazing and increased protein in the forage from the clover-grass
pastures were the explanation for increased reproduction. There
was also the possibility that some factors) other than protein
was responsible for increased reproduction. It is important to
remember that whatever the responsible factor it is one which
carries over into later reproduction, since all females were on
the same grazing program after two years of age. A carry-over
effect from the nutritional regime during the first winter on
subsequent reproduction in sheep has been shown by Esplin
et al. (3).
Winter program had a significant (P<0.01) influence on
weights of cows that weaned calves (Table 5). The lowest
cow weights were observed in the grass L.P. group with an
average of 882 pounds, while the clover-grass H.P. group had
an average weight of 958 pounds. The two clover-grass groups
of cows averaged 47 pounds heavier than the grass groups,
while the high protein groups averaged 29 pounds more than
the low protein group.
The increased weights of heifers and cows raised on the
clover-grass pastures were probably because their plane of
nutrition was better than for those on the all-grass pastures.
The increased body weights, resulting in a more mature repro-
ductive system in young cows, probably contributed to the higher
reproductive rate of heifers grown on the clover-grass pastures.

Weaning Data
Effects of Winter Program-Winter program had no signifi-
cant effect on age, adjusted daily gain, or slaughter grade of
calves at weaning (Table 5). However, the calves from the
grass L.P. group were approximately 10 days younger (Table 5)
than those from the grass H.P. group, suggesting a longer in-
terval to first estrus for cows in the former group.

SUMMARY
Crossbred heifers sired by Angus, Brahman, Hereford, and
Shorthorn bulls mated to Brahman-Native cows were assigned
to one of the following pasture and winter supplemental feeding
programs during their first two winters after weaning: 1)
grass pasture, low protein; 2) grass pasture, high protein; 3)
clover-grass pasture, low protein; and 4) clover-grass pasture,







Florida Agricultural Experiment Stations


high protein. The high protein group received 1 to 2.5 pounds
daily of protein supplement for approximately three to five
months, depending on forage production, while the low protein
groups received a minimum amount of protein which varied
from 0 to 1 pound daily. After the second winter period and
for the subsequent years, females were bred during a three-
month breeding season, and the calves were weaned at ap-
proximately seven months of age without creep feeding. All
cows were handled similarly after entering the breeding herd
and given supplement only during the winter, when forage pro-
duction was inadequate. Reproductive response was measured
by calving and weaning percentages. Weaning data included
age of calves, daily gain, and slaughter grade.
Heifers raised on clover-grass pastures were 104 pounds
heavier at 30 months of age than those on straight grass pas-
tures, while heifers receiving the high protein supplement were
40 pounds heavier than the low protein groups. The weight of
cows raised on clover-grass pastures was 47 pounds more than
for cows raised on grass pasture. Cows from the high protein
supplementation groups were 29 pounds heavier than those
from the low protein groups.
The different programs had a significant effect (P<0.05) on
calving percentage. The heifers raised on clover-grass pastures
had a 96 percent calving rate compared to 81 percent for heifers
raised on grass pastures. The weaning percentage for the
heifers raised on clover-grass was 89 versus 76 for those raised
on grass pastures. Heifers fed a high protein level had an 89
percent calving rate compared to 88 percent for those heifers
on a low protein level. Program under which replacement heifers
were grown had no significant effect on age, daily gain, or
slaughter grade of their calves at weaning.
It is recommended that heifers be raised on clover-grass
pasture rather than grass alone whenever soil and moisture
conditions permit in order to obtain higher calving rates and
increased body weight of cows. It appears that these traits
are affected more by type of pasture on which replacement
heifers are grown than by level of winter protein supplement
fed.








Productivity of Beef Cows 15


LITERATURE CITED

1. Anderson, R. L. and T. A. Bancroft. Statistical theory in research. 1st
Edition, McGraw-Hill Book Co., N.Y., N.Y. 1952.
2. Bohman, V. R., and C. Torell. Protein supplements for wintering beef
cattle. J. Animal Sci. 15:1253. 1956.
3. Esplin, A. C., M. A. Madsen, and R. W. Phillips. Effects of feeding ewe
lambs during their first winter. Utah Agri. Expt. Sta. Bul. 292. 1940.
4. Koger, M., W. G. Blue, G. B. Killinger, R. E. L. Greene, H. C. Harris,
J. M. Meyers, A. C. Warnick, and N. Gammon, Jr. Beef production, soil
and forage analysis, and economic returns from eight pasture programs
in North Central Florida. Fla. Agri. Expt. Sta. Bul. 631. 1961.
5. Lewis, L. H., T. J. Cunha, and G. N. Rhodes. Beef cattle in Florida. Fla.
Dept. of Agri. Bul. 28. 1961.
6. Nelson, A. B., R. MacVicar, J. P. Fontenot, and A. E. Darlow. Relative
value of supplements of varying protein content for wintering heifer
calves. J. Animal Sci. 11:786. 1952.
7. Pinney, D., L. S. Pope, K. Urban, and D. Stephens. Winter feeding
studies with beef heifers. Okla. Agri. Expt. Sta. M.P. 64. 1961.




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