The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
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site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Bulletin 410 April, 1945
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
in cooperation with
Bureau of Animal Industry, United States Department
COMPARISON OF PUREBRED AND
CROSSBRED COCKERELS WITH
RESPECT TO FATTENING AND
N. R. MEHRHOF, W. F. WARD and 0. K. MOORE
Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
BOARD OF CONTROL ECONOMICS, AGRICULTURAL
H. P. Adair, Chairman, Jacksonville C. V. Noble, Ph.D., Agr. Economist' 3
N. B. Jordan, Quincy Zach Savage, M.S.A., Associates
ST S L O A. H. Spurlock, M.S.A., Associate
. akMax E. Brunk, M.S., Associate
Thos. W. Bryant, Lakeland
M. L. Mershon, Miami
J. T. Diamond, Secretary, Tallahassee ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.1
EXECUTIVE STAFF R. B. French, Ph.D., Biochemist
John J. Tigert, M.A., LL.D., President of the ENTOMOLOGY
H. Harold Hume, D.Sc., Provost for Agricul- J. R. Watson, A.M., Entomologist'
ture A. N. Tissot, Ph.D., Associate3
Harold Mowry, M.S.A., Director H. E. Bratley, M.S.A., Assistant
L. O. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifield, M.S., Asst. Dir., Admin.4 HORTICULTURE
J. Francis Cooper, M.S.A., Editor3
Clyde Beale, A.B.J., Assistant Editor3 G. H. Blackmon, M.S.A., Horticulturist'
Jefferson Thomas, Assistant Editors
Ida eeling Cresap, Librarian A. L. Stahl, Ph.D., Asso. Horticulturist
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager' F.S. Jamison, Ph.D., Truck Hort.
K. H. Graham, LL.D., Business Managers R. J. Wilmot, M.S.A., Asst. Hort.
Claranelle Alderman, Accountants R. D. Dickey, M.S.A., Asst. Hort.'
Victor F. Nettles, M.S.A., Asst. Hort.'
J. Carlton Cain, B.S.A., Asst. Hort.'
MAIN STATION, GAINESVILLE Byron E. Janes, Ph.D., Asst. Hort.
F. S. Lagasse, Ph.D., Asso. Hort.2
W. E. Stokes, M.S., Agronomist' PLANT PATHOLOGY
Fred H. Hull, Ph.D., Agronomist
G. E. Ritchey, M.S., Agronomist3 W. B. Tisdale, Ph.D., Plant Pathologist'
G. B. Killinger, Ph.D., Agronomist Phares Decker, Ph.D., Asso. Plant Path.
W. A. Carver, Ph.D., Associate Erdman West, M.S., Mycologist
Roy E. Blaser, M.S., Associate Lillian E. Arnold, M.S., Asst. Botanist
H. C. Harris, Ph.D., Associate
R. W. Bledsoe, Ph.D., Associate SOILS
Fred A. Clark, B.S., Assistant
F. B. Smith, Ph.D., Chemist1 3
ANIMAL INDUSTRY Gaylord M. Volk, M.S., Chemist
J. R. Henderson, M.S.A., Soil Technologist
A. L. Shealy, D.V.M., An. Industrialist' 3 J. R. Neller, Ph.D., Soils Chemist
R. B. Becker, Ph.D., Dairy Husbandman3 C. E. Bell, Ph.D., Associate Chemist
E. L. Fouts, Ph.D., Dairy Technologist3 L. H. Rogers, Ph.D., Associate Biochemist'
D. A. Sanders, D.V.M., Veterinarian R. A. Carrigan, B.S., Asso. Biochemist
M. W. Emmel, D.V.M., Veterinarian3 G. T. Sims, M.S.A., Associate Chemist
L. E. Swanson, D.V.M., Parasitologist4 T. C. Erwin, Assistant Chemist
N. R. Mehrhof, M.Agr., Poultry Husb.3 H. W. Winsor, B.S.A., Assistant Chemist
T. R. Freeman, Ph.D., Asso. in Dairy Mfg. Geo. D. Thornton, M.S., Asst. Microbiologist
R. S. Glasscock, Ph.D., An. Husbandman R. E. Caldwell, M.S.A., Asst. Soil Surveyor'
D. J. Smith, B.S.A.. Asst. An. Husb.4
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.s Olaf C. Olson, B.S., Asst. Soil Surveyor
G. K. Davis, Ph.D., Animal Nutritionist
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.4 I Head of Department.
J. E. Pace, B.S., Asst. An. Husbandman 2 In cooperation with U. S.
S. P. Marshall, M.S, Asst. in An. Nutrition C o d
C. B. Reeves, B.S., Asst. Dairy Tech. Cooperative, other divisions, U. of F.
Katherine Boney, B.S., Asst. Chem. In Military Service.
Ruth Faulds, A.B., Asst. Biochemist 8 On leave.
Peggy R. Lockwood, B.S., Asst. in Dairy Mfs.
BRANCH STATIONS SUB-TROPICAL STA., HOMESTEAD
NORTH FLORIDA STATION, QUINCY Geo. D. Ruehle, Ph.D., Vice-Director in
J. D. Warner, M.S., Vice-irector in Charge P. Westgate, Ph.D., Asso. Horticulturist
R. R. Kincaid, Ph.D., Plant Pathologist H. I. Borders, M.S., Asso. Plant Path.
V. E. Whitehurst, Jr., B.S.A., Asst. Animal
Hush.4 W. CENT. FLA. STA., BROOKSVILLE
Jesse Reeves, Asst. Agron., Tobacco
W. H. Chapman, M.S., Asst. Agron.* Clement D. Gordon, Ph.D., Asso. Poultry
W. C. Bond M.S.A., Asst. Agronomist Geneticist in Charge.
R. C. Bond, M.S.A., Asat. Agronomist Geneticist in Charge"
RANGE CATTLE STA., ONA
Mobile Unit, Monticello
W. G. Kirk, Ph.D., Vice-Director in Charge
R. W. Wallace, B.S., Associate Agronomist E. M. Hodges, Ph.D., Asso. Agron., Wauchula
Gilbert A. Tucker, B.S.A., Asst. An. Husb.4
Mobile Unit, Milton
Ralph L. Smith, M.S., Associate Agronomist FIELD STATIONS
Mobile Unit, Marianna G. K. Parris, Ph.D., Plant Path. in Charge
R. W. Lipscomb, M.S., Associate Agronomist
Mobile Unit, Wewahitchka A. N. Brooks, Ph.D., Plant Pathologist
J. B. White, B.S.A., Associate Agronomist Hastings
A. H. Eddins, Ph.D., Plant Pathologist
CITRUS STATION, LAKE ALFRED E. N. MeCubbin, Ph.D., Truck Horticulturist
A. F. Camp, Ph.D., Vice-Director in Charge Monticello
V. C. Jamison, Ph.D., Soils Chemist
B. R. Fudge, Ph.D., Associate Chemist S. 0. Hill, B.S., Asst. Entomologist2 4
W. L. Thompson, B.S., Entomologist A. M. Phillips, B.S., Asst. Entomologist2
W. W. Lawless, B.S., Asst. Horticulturist'
C. R. Stearns, Jr., B.S.A., Asso. Chemist Bradenton
H. O. Sterling, B.S., Asst. Horticulturist J. R. Beckenbach, Ph.D., Horticulturist in
T. W. Young, Ph.D., Asso. Horticulturist Charge
J. W. Sites, M.S.A., Asso. Horticulturist" E. G. Kelsheimer, Ph.D., Entomologist
Ross F. Suit, Ph.D., Plant Pathologist D. B. Creager, Ph.D., Plant Path., Gladiolus
A. L. Harrison, Ph.D., Plant Pathologist
EVERGLADES STA., BELLE GLADE David G. Kelbert, Asst. Plant Pathologist
E. L. Spencer, Ph.D., Soils Chemist
R. V. Allison, Ph.D., Vice-Director in Charge
J. W. Wilson, Sc.D., Entomologist' Sanord
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane R. W. Ruprecht, Ph.D., Chemist in Charge
Physiologist J. C. Russell, M.S., Asst. Entomologist6
G. R. Townsend, Ph.D., Plant Pathologist
R. W. Kidder, M.S., Asst. An. Hush. Lakeland
W. T. Forsee, Jr., Ph.D., Asso. Chemist E. S. Ellison, Meteorologist 2 5
B. S. Clayton, B.S.C.E., Drainage Eng.2 Warren O. Johnson, Meteorologist-
F. S. Andrews, Ph.D., Asso. Truck Hort.'
R. A. Bair, Ph.D., Asst. Agronomist 1 Head of Department.
E. C. Minnum, M.S., Asst. Truck Hort. 'In cooperation with U. S.
N. C. Hayslip, B.S.A., Asst. Entomologist 3 Cooperative, other divisions, U. of F.
Earl L. Felix, Ph.D., Asst. Plant Path. In Military Service.
C. L. Serrano, B.S.A., Asst. Chemist 6 On leave.
INTRODUCTION ............. ... ............-...-..--.... ... -................ 5
REVIEW OF LITERATURE ......... ....... ..... .......... .. ................................. 5
EXPERIMENTAL PROCEDURE ..... --..............--.... ..................--............ 7
Birds U sed ................................. ..... ............ .. .......... ...... 7
Housing and Equipm ent ............................. ............ ....................... 8
Feeding and Management ......................... ......-------------.......-..... 8
RESULTS AND DISCUSSION ...---....-............. ---------- ---.......--....--.... 10
Rate of Growth ......................... ....................................... 10
Feed Utilization -...................------------.. ....... ..........-...-..-- .... 11
Shrinkage in Transit ......---.................. --- ---............... 11
Dressing Losses ..............--....... -.........--------...... .... 12
Drawing Losses ............---........ ..--.. -------------. 12
Live and Dressed Grading ...-..---..----.. ... .....----------..---. 12
SUMMARY ......--...-- ...... --.--- -------------------------...... ..... ---..... ...- 14
LITERATURE CITED -...---------- -- ------........ ------.... ............. .............. 16
COMPARISON OF PUREBRED AND CROSSBRED
COCKERELS WITH RESPECT TO FATTENING
AND DRESSING QUALITIES'
N. R. MEHRHOF, W. F. WARD 2 and 0. K. MOORE 3
In recent years commercial production of broilers and fryers
has become an important phase of the poultry industry of
Florida. Various problems confront Florida broiler producers,
including the relative merits of pure breeds of chickens as com-
pared with cross breeds. This bulletin reports results of ex-
periments comparing purebred and crossbred cockerels fattened
for a 14-day period on a uniform ration commencing when the
birds were 10 weeks of age. Consideration was given to rate
of growth, efficiency of feed utilization, shrinkage in transit,
dressing and drawing losses, and quality of live birds and dressed
carcasses. Results secured from these experiments-which in-
dicate the various losses sustained in marketing channels in
preparing poultry for the consumer-should interest producers,
marketing agencies and consumers.
REVIEW OF LITERATURE
Weight changes during fattening periods have been reported
by many investigators. There is considerable variation in these
weight changes due in part to type of ration, length of fattening
period, weight or age of bird, and breed of chickens. Harshaw
(2)4 observed that the feed consumed during the fattening
period per unit of gain in live weight increased with the age
of the bird, and that the absolute gain in live weight during
the fattening period increased but the relative gain decreased
SThese investigations were conducted cooperatively at the West Central
Florida Experiment Station (Chinsegut Hill Sanctuary) by the Bureau of
Animal Industry, United States Department of Agriculture, and 'Poultry
Division, Department of Animal Industry, Florida Agricultural Experiment
"2 Formerly Animal Husbandman in Charge, West Central Florida Ex-
8 The authors are indebted to W. T. Morgan and Miss Lillie Brummerhof,
who managed the birds in this experiment.
SItalic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.
6 Florida Agricultural Experiment Station
Feed consumption in pounds of feed per pound of gain varied
considerably in a number of experiments. Funk, Kempster and
Bryan (1) found that the pounds of feed to produce a pound
of gain during a 10-day fattening period varied from 2.5 to 4.2
pounds with Plymouth Rock broilers; 2.8 to 4.0 pounds with
Rhode Island Reds, and 2.6 to 4.2 pounds with White Leghorns.
These birds were fed different levels of milk products. Harshaw
reported that 8-weeks-old cockerels during a 14-day feeding trial
required 3.96 pounds of feed per pound of gain, and that 12-
weeks-old birds required 4.59 pounds of feed per pound of gain.
Jull and Maw (5) pointed out that medium-sized chickens
required a fattening period of about 2 weeks. Birds averaging
3.06 pounds in weight required 4.25 pounds of feed for each
pound of gain during the 3-week fattening period; birds weigh-
ing 2.87 pounds during a 2-week fattening period required 3.46
pounds of feed per pound of gain; and birds weighing 2.76
pounds required 4.41 pounds of feed per pound of gain during
a 10-day fattening period. Hepburn and Holder (3) reported
on 14-day fattening experiments using different rations with
birds weighing at the start from 1.3 to 2.4 pounds and found
that from 2.19 to 4.79 pounds of feed were required for each
pound of gain.
The percentage of gain during a fattening period of 10 days,
according to Funk, Kempster and Bryan, with Plymouth Rocks,
Rhode Island Reds and Leghorn broilers was 25.7, 24.1 and 29.6
percent, respectively, with an average gain of 26.3 percent for
all broilers. Harshaw found that cockerels from Barred Ply-
mouth Rock-Rhode Island Red crossbred females mated to White
Leghorn males gained 48.15 percent at 8 weeks during a 14-day
feeding trial; 27.30 percent at 12 weeks; and 18.75 percent for
16-weeks-old birds. Hepburn and Holder stated that broilers
gained an average of 40.16 percent of the initial weight during
a 14-day feeding period. Jull and Maw (5) reported that in a
3-week fattening period birds averaging 3.06 pounds in weight
gained 35.50 percent; while birds weighing 2.76 pounds gained
23.78 percent during a 10-day fattening period.
Experiments to determine the dressing and drawing losses
in broilers and fryers have been reported by several workers.
Funk, Kempster and Bryan found a dressing loss of 11.5 per-
cent with Plymouth Rock broilers, 11.7 percent with Rhode
Island Reds, and 12.3 percent with White Leghorns. Birds
weighing 3.29 pounds shrank 14.76 percent in dressing, while
Comparison of Fattening Qualities of Cockerels 7
the drawn weight was 69.61 percent of the live weight, accord-
ing to Vernon (11). Mairs (7) reported that 5.7 percent of
the live weight was blood and 8.46 percent was feathers in
White Leghorn pullets weighing 2.54 pounds. In Barred Ply-
mouth Rock cockerels weighing 3.23 pounds blood constituted
4.02 percent and feathers 8.36 percent of the live weight. Lowe
and Vernon (6) found that the dressed weights of broilers and
fryers were 89.1 and 89.8 percent of the live weights and the
drawn weights were 62.9 and 67.8 percent of the live weights,
respectively. According to Hepburn and Holder, blood con-
stituted 4.01 percent and feathers 6.45 percent of the live weight
of broilers. Jull and Maw (4) reported that in unfattened
broilers weighing 2.65 pounds the dressed weight was 88.30 .72
percent of live weight, while with fattened broilers weighing
2.72 pounds the dressed weight was 90.81 .38 percent.
Blood and feathers constituted 11.26 and 10.80 percent and
the heart, liver and gizzard 5.11 and 4.52 percent, respectively,
of the live weight of Single Comb White Leghorns weighing
approximately 2 and 3 pounds, according to data of Mitchell,
Card and Hamilton (10). Maw (8) stated that medium-sized
birds, at the end of a 2-week fattening period, dressed out
120.87 percent of what they weighed at the beginning of the
fattening period. They dressed 89.35 percent of the final live
weight. Blood was 5.8 percent, feathers 3.1 percent, and giblets
9 percent of the final live weight. Harshaw reported that the
ratio of dressed weight to live weight was very close to 89 per-
cent at all ages, whether birds were fattened or not. Accord-
ing to Mitchell, Card and Hamilton (9), "the offal part (feathers,
blood, head, shanks and feet) of the carcass of White Plymouth
Rocks, not including the inedible viscera, was found to con-
stitute a fairly constant percentage of the empty weight of the
birds at all weights, namely very close to 19 percent."
Eight fattening trials with purebred and crossbred cockerels
were conducted at the West Central Florida Experiment Station,
Brooksville, Florida, and the birds were delivered to the Main
Station, Gainesville, Florida, for grading and studies of shrink-
age in transit and dressing losses.
Birds Used.-In these trials the following purebred or cross-
bred cockerels were used: Light Sussex, Single Comb Rhode
Island Red, Single Comb Rhode Island Red-Light Sussex cross
8 Florida Agricultural Experiment Station
(2-way cross), female progeny of Single Comb Rhode Island Red-
Light Sussex cross mated to Single Comb White Leghorn male
(3-way cross), and female progeny of Single Comb Rhode Island
Red-Light Sussex cross mated to Barred Plymouth Rock male
(3-way cross).5 The Light Sussex and Rhode Island Red purebred
birds and the purebred birds from which the Light Sussex
and Rhode Island Red blood was derived which was carried by
the 2-way and 3-way crossbred birds were of the same strains.
At 10 weeks of age the cockerels for each lot were selected
as uniform as possible in weight and condition. Table 1 shows
the different purebred and crossbred birds used in these trials,
together with the number of cockerels in each lot and trial for
the 3-year period. There were 19 lots and a total of 459 cockerels
in the experiment. All lots of cockerels were fattened in bat-
Housing and Equipment.-The fattening batteries were located
in a ventilated building with insulated walls and ceiling. The
room temperature usually was about the same as or 1 degree
cooler than the atmospheric temperature.
Feeding and Management.-All birds in each lot received a
uniform fattening mash to which sufficient water had been added
to give a consistency of thick batter. This mixture was fed in
quantities which would be consumed in approximately 30 min-
utes at 7:30 A.M., 12:30 P.M. and 5:30 P.M. daily. Water was
available at all times. The fattening period was 14 days in
duration. The dropping pans, feed and water troughs were
cleaned thoroughly daily.
The cockerels were weighed at the end of the trials between
7:30 A.M. and 8:15 A.M. They were cooped; left the West
Central Florida Experiment Station by motor vehicle at about
8:30 A.M., and arrived at the Main Station about 11:00 A.M.
The birds were weighed on arrival, graded according to U. S.
SIn this publication the following symbols will designate the pure breeds
and cross breeds used in these trials in the tables and text:
1. Light Sussex-L.S.
2. Single Comb Rhode Island Red-R.I.R.
3. Single Comb Rhode Island Red male mated to the Light Sussex
female-R.I.R. x L.S.
4. The female progeny of the Single Comb Rhode Island Red-Light
Sussex cross mated to a Single Comb White Leghorn male-W.L. x
Fi(R.I.R. x L.S.).
5. The female progeny of the Single Comb Rhode Island Red-Light
Sussex cross mated to a Barred Plymouth Rock male-B.P.R. x
FI(R.I.R. x L.S.).
TABLE 1.-NUMBER OF COCKERELS USED IN EXPERIMENT, BY BREEDS AND TRIALS. o
1940 1941 1942
Breed Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Total
Lot No. Lot No. Lot No. Lot No. Lot No. Lot No. Lot No. Lot No. I
_No. Birds No. Birds No. Birds No. Birds No. Birds No. Birds No. Birds No. Birds _
Light Sussex ................ 1 25 4 25 8 25 13 13 88
Rhode Island Red ........ 7 25 10 25 17 25 75
R.I.R.xL.S. ............... 2 2 5 25 9 25 11 25 14 25 16 25 19 24 21 24 198
W.L.xFi(R.I.R.xL.S.) 3 25 6 25 50
B.P.R.xFi(R.I.R.xL.S.) 20 24 22 24 48
TOTAL ................... | 75 100 75 25 38 50 48 48 459
10 Florida Agricultural Experiment Station
grades for live poultry, dressed, graded according to U. S. grades
for dressed poultry, and drawn. Records were kept on the
weights of dressed and drawn birds, and on the combined weight
of the liver, heart and gizzard.
Ingredients Parts by Weight
Yellow corn meal .........-----......... ...-------....... ---39.0
Fine ground oats .......-----....--.... .-- ....--- ..------- 34.0
Meat scraps ..........--- ... -----....--..-- ..-......-- ---... 13.0
Dried buttermilk .-........--------------...- .-- -..... .... 7.0
Alfalfa leaf meal ................. ..... ------...-- ....-- ..--- 5.0
Ground oyster shell --.......-.-........--............------ .... 1.5
Com m on salt .........----.......... -- .........-- .... .............. 0.5
TOTAL .-.....---.. ----....---.....--------.. 100.0
RESULTS AND DISCUSSION
Rate of Growth.-Table 2 shows the average weight of the
cockerels at the start and at the end of the 14-day fattening
periods, together with gain in grams and the percent of gain
for the different purebred and crossbred cockerels.
Considerable variation occurred in actual gains and in percent
gain in the prebred and crossbred birds during the several trials.
The lighter-weight cockerels on the average made the most gain
with the exception of the W.L. x Fi(R.I.R. x L.S.). The cross-
breds were heavier than the purebreds at 10 weeks of age and,
except for the W.L. x FI(R.I.R. x L.S.) cockerels, they were
also heavier at 12 weeks. However, the greatest percentage of
gain was made by the R.I.R. cockerels, followed by the L.S.
cockerels. These, as noted in Table 2, were the lighter weight
cockerels. The 2 3-way crosses made about the same percentage
TABLE 2.-AVERAGE WEIGHT OF COCKERELS AT START AND END OF 14-DAY
FATTENING PERIOD, GAIN IN GRAMS AND PERCENT.
S Average Average
Number Weight Weight |
Breed or of at 10 at 12 Average Gain
Cross Breed Birds Weeks Weeks I_
S(Grams) I (Grams) [ Grams | Percent
Light Sussex .....----....... .. 88 882.02 1,268.73 386.70 43.84
Rhode Island Red ............ 75 820.85 1,191.59 370.73 45.16
R.I.R.xL.S .-..-..............-- .... 198 958.14 1,346.31 388.17 40.51
W.L.xF (R.I.R.xL.S.) ...... 50 895.66 1,211.54 315.88 35.27
B.P.R.xF (R.I.R.xL.S.) .... 48 1,005.60 1,362.08 356.48 35.45
Comparison of Fattening Qualities of Cockerels 11
Feed Utilization.-As shown in Table 3, the R.I.R. x L.S.
cockerels used their feed most efficiently, the W.L. x F (R.I.R.
x L.S.) cockerels least efficiently. The R.I.R. group ranked
second, followed by the B.P.R. x FI(R.I.R. x L.S.) and L.S.
gri s. For the 5 groups the amount of feed required for each
gfim of gain during the 14-day feeding period varied from 3.85
to -5.54 grams.
These results indicate that the 2-way cross consisting of a
R.I.R. male mated to L.S. females was more efficient in the
conversion of feed into poultry meat than either R.I.R. or L.S.
The, addition of W.L. blood to the 2-way cross tended to reduce
util tztion of feed in comparison with either the 2-way cross
or tle 2 purebreds.
TABLE 3.-FEED CONSUMPTION AND GAIN MADE DURING A 14-DAY FEEDING
PERIOD, AND GRAMS OF FEED PER GRAM OF GRAIN.
Number Consumption Grams of
Breed or of per Bird Gain Feed per
Cross Breed Birds 14 Days (Grams) Gram of
(Grams) I Gain
Light Stssex ................. 88 1,829.86 386.70 4.73
Rhode nd Red .------...... 75 1,481.76 370.73 4.00
R.I. ....... ........ 198 1,495.28 388.17 3.85
W.L. (R.I.R.xL.S.) .... 50 1,750.90 315.88 5.54
B.P.R FF(R.I.R.xL.S.) 48 1,611.23 356.48 4.52
Shrinkage in Transit.-Shrinkage losses as a result of transit
from Brooksville to Gainesville (a distance of approximately
100 miles) on the average ranged from 2.76 percent for the
B.P.R. x F (R.I.R. x L.S.) to 4.14 percent for the L.S., as shown
in Table 4.
TABLE 4.-SHRINKAGE OBSERVED: 12-WEEKS-OLD FATTENED COCKERELS
TRANSPORTED BY MOTOR VEHICLE FROM BROOKSVILLE TO GAINESVILLE,
Breed or Number (Grams) (Grams) Shrinkage
Cross Breed of at at
Birds Brooks- Gaines-
ville, ville, Grams Percent
12 Weeks 12 Weeks_
Light Sussex ...........----....... 88 1,268.73 1,216.24 52.49 4.14
Rhode Island Red ..---....... 75 1,191.59 1,144.49 47.10 3.95
R.I.R.xL.S. _...................... 198 1,346.29 1,297.30 48.99 3.64
W.L.xFi(R.I.R.xL.S.) ...... 50 1,211.54 1,162.90 48.64 4.01
B.P.R.xFi(R.I.R.xL.S.) .. 48 1,362.08 1,324.42 37.66 2.76
12 Florida Agricultural Experiment Station
Unpublished data of the Florida Agricultural Experiment
Station are available on unfattened, range-reared R.I.R. and
R.I.R. x L.S. (2-way) cockerels of the same age and strain as
the battery-fattened cockerels reported in this publication. The
battery-fattened birds, when compared by breeds with le
range-reared, unfattened birds, had the greatest shrinkage fn
transit. Shrinkage loss of the unfattened, range-reared R.I:R.
cockerels was 3.35 percent, compared with 4.65 percent for
the battery-fattened cockerels of the same breed. Shrinkage
loss of the unfattened, range-reared 2-way cross was 2.72 per-
cent, compared with 4.38 percent for the battery-fattened c6ick-
erels of the same cross.
Dressing Losses.-After the birds were weighed at the Main
Station and graded according to U. S. Standards for liv. birds,
they were dressed. Table 5 shows the average live weight,
dressed weight, weight of blood and feathers, and the percentage
of each in comparison with the live weight. Blood and feathers
expressed in percent of the live weight varied on the average
from 9.82 percent for the R.I.R. cockerels to 10.99 percent for
the W.L. x F (R.I.R. x L.S.) cockerels. These figures iLdicate
that the differences in dressing loss of the various lots conslered
in the experiment were inappreciable, since the maximuiR dif-
ference among lots was 1.17 percent. The data indicatkthat
blood and feather losses in dressing amount to approximately
10 percent of the live weight.
Drawing Losses.-The dressed birds were then fully drawn.
Table 6 gives the drawn weight (without heart, liver and giz-
zard), weight of heart, liver and gizzard, and the percentage
of each in comparison with the live weight. The drawn weight
varied from 63.30 percent for the B.P.R. x FI(R.I.R. x L.S.)
cockerels to 64.68 percent for the W.L. x F1 (R.I.R. x L.S.) cock-
erels. The total shrinkage expressed as a percentage of live
weight varied from 30.17 for the L.S. to 31.21 for the B.P.R. x
F (R.I.R. x L.S.) cockerels. The difference in total shrinkage
of the various lots studied was 1.04 percent. These data indicate
that the drawn bird, including the heart, liver and gizzard,
weighs approximately 70 percent of the live weight, giving a
total dressing and drawing loss of about 30 percent.
There was considerable variation in the weight of the liver,
heart and gizzard of the various lots of cockerels.
Live and Dressed Grading.-U. S. grades for live poultry are
A, B and C, for dressed poultry AA, A, B and C. For the pur-
TABLE 5.-LIVE AND DRESSED WEIGHT PER COCKEREL, IN GRAMS AND PERCENTAGE BY BREEDS AND CROSS BREEDS
BASED ON LIVE WEIGHT.
Breed or Number of Live Weight of Blood Dressed Weight
Cross Breed Birds Weight and Feathers
(Grams) Grams Percent Grams Percent
Light Sussex ................................ 88 1,216.24 123.17 10.13 1,093.07 89.87
Rhode Island Red .......................... 75 1,144.49 112.40 9.82 1,032.09 90.18
R.I.R.xL.S .................... .. ............. 198 1,297.30 139.78 10.77 1,157.52 89.23
W.L.xFi(R.I.R.xL.S.) .................... 50 1,162.90 127.84 10.99 1,035.06 89.01
B.P.R.xF1(R.I.R.xL.S.) ....................... 48 1,324.42 131.82 9.95 1,192.60 90.05
TABLE 6.-LIVE, DRAWN, AND GIBLETS WEIGHTS PER COCKEREL, IN GRAMS AND PERCENTAGE OF LIVE
WEIGHT BY BREEDS AND CROSS BREEDS.
Number Live D
Breed or of Weight Drawn Weight Giblets I Total Shrinkage
Cross Breed Birds (Grams) Grams Percent Grams Percent Grams I Percent
------------------------------------- O z
Light Sussex ................ 88 1,216.24 784.97 64.54 64.35 5.29 366.92 30.17
Rhode Island Red ............ 75 1,144.49 739.16 64.58 55.77 4.87 349.56 30.54
R.I.R.xL.S. ....................... 198 1,297.30 827.07 63.75 65.43 5.04 404.80 31.20
W.L.xFI(R.I.R.xL.S.) ............ 50 1,162.90 752.16 64.68 53.30 4.58 357.44 30.74
B.P.R.xF,(R.L.R.xL.S.) .. 48 1,324.42 838.38 63.30 72.74 5.49 413.30 31.21
1Without heart, liver and gizzard.
SHeart, liver and gizzard.
14 Florida Agricultural Experiment Station
pose of these studies the following numerical values were as-
signed to the different grades: Live poultry, A equals 100,
B equals 90 and C equals 80; for dressed poultry, AA eql'.ls
100, A equals 90, B equals 80 and C equals 70. Thus the dresseI
birds can grade higher, even though the numerical scores as-
signed them are somewhat lower.
Table 7 shows the percentage of birds placed in each grade,
live and dressed. It also gives the average score for each lot.
Average scores, on a live basis, by lots were: R.I.R. x L.,,
96.53; L.S., 96.25; B.P.R. x FI(R.I.R. x L.S.), 95.74; R.I. .,
95.47; and W.L. x FI(R.I.R. x L.S.), 93.40. A few birds wse
placed in Grade C because of crooked breasts or slight br st
blisters, and only 1 bird was rejected.
In the dressed grades it will be noted that the percentage
grading AA and A increased in comparison with the percentage
grading A in live grading. This indicates that the birds whjh
were graded B in live grading were placed in that grade primary
because of the feathering.
The L.S. and R.I.R. x L.S. cockerels were the easiest of All
birds to dress. The 2-way crosses were easier to dress than 'the
The average score of each lot when graded according to U; S.
standards for dressed poultry was L.S., 89.55; R.I.R. x L.S.,
87.91; R.I.R., 87.87; W.L. x FI(R.I.R. x L.S.), 87.40; and B.P.R.
x FP(R.I.R. x L.S.), 87.02. There was little difference between
the R.I.R., R.I.R. x L.S. and the two 3-way crosses. The live
and dressed scores indicate that little correlation exists between
live grades and dressed grades. Live grading is not an adequate
prediction of quality in dressed birds.
Various purebred and crossbred cockerels 10 weeks of age
were compared as to gain and feed utilization for a 2-weeks
fattening period, live and dressed grading, dressing and draw-
ing losses, and shrinkage in transit. A total of 459 cockerels
were used in this experiment.
The average gain in body weight in grams during the 14-day
fattening period was as follows: R.I.R. x L.S., 388.17; L.S.,
386.70; R.I.R., 370.73; B.P.R. x F1(R.I.R. x L.S.), 356.48; W.L.
x FI(R.I.R. x L.S.), 315.88.
The average grams of feed required per gram of gain were
as follows: W.L. x F (R.I.R. x L.S.), 5.54; L.S., 4.73; B.P.R.
TABLE 7.-NUMBER AND PERCENTAGE OF COCKERELS IN EACH GROUP ACCORDING TO GRADES,
AND THE AVERAGE SCORES BY BREEDS.
Breed or Distribution by Live Grades
Cross Breed Number of Grade Grade Grade Average
Birds A B C Reject Score
No. Percent I No. Percent No. Percent No. Percent
Light Sussex ............ ... ...... 88 56 63.64 31 35.23 1 1.13 96.25
Rhode Island Red ........................... 75 41 54.67 34 45.33 95.47
R.I.R.xL.S. .............................. 196 143 72.96 46 23.47 6 3.06 1 0.51 96.53
W.L.xFI(R.I.R.xL.S.) .................. 50 21 42.00 25 50.00 | 4 8.00 93.40
B.P.R.xFd(R.I.R.xL.S.) ............ 47 27 57.45 20 42.55 95.74
Breed or Distribution by Dressed Grades
Cross Breed Grade Grade Grade Grade Average
AA A B C Reject Score "
No. Percent No. Percent No. Percent No. Percent No. Percent 0
Light Sussex ..................... ....... 9 10.23 66 75.00 13 14.77 89.55
Rhode Island Red ........................ 3 4.00 55 73.33 15 20.00 2 2.67 87.87
R.I.R.xL.S. ..................................... 16 8.16 139 70.92 32 16.33 8 4.08 1 0.51 87.91 o
W.L.xF1(R.I.R.xL.S.) ................. 37 74.00 13 26.00 87.40
B.P.R.xF1(R.I.R.xL.S.) .................. 36 76.60 8 17.02 3 6.38 87.02
16 Florida Agricultural Experiment Station
x Fi(R.I.R. x L.S.), 4.52; R.I.R., 4.00; R.I.R. x L.S., 3.85.
The average percent shrinkage of body weight in transit, a
distance of approximately 100 miles, was as follows: L.S., 4.14,;
W.L. x FI(R.I.R. x L.S.), 4.01; R.I.R., 3.95; R.I.R. x L.S., 3.64;
B.P.R. x Fi(R.I.R. x L.S.), 2.76.
The average percent total shrinkage of weight in dressing
and drawing was as follows: B.P.R. x F1(R.I.R. x L.S.), 31.21;
R.I.R. x L.S., 31.20; W.L. x FI(R.I.R. x L.S.), 30.74; R.I.R.,,
30.54; L.S., 30.17.
Average scores for the birds graded alive were as follows:
R.I.R. x L.S., 96.53; L.S., 96.25; B.P.R. x FI(R.I.R. x L.S.),
95.74; R.I.R., 95.47; W.L. x FI(R.I.R. x L.S.), 93.40.
Average scores for the birds graded dressed were as follows:
L.S., 89.55; R.I.R. x L.S., 87.91; R.I.R., 87.87; W.L. x Fi (R.I.R.
x L.S.), 87.40; B.P.R. x F (R.I.R. x L.S.), 87.02.
The results of these experiments indicate, for the strains used,
that the 2-way cross, in general, was superior, followed by the
purebreds and 3-way crosses.
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19( j /P