Research 
Update
Research Update
1989
POULTRY
FIRST IN POULTRY UPDATE
SERIES
This is the first poultry re-
search report published in a new
publication series, entitled "Re-
search Update," inaugurated in 1989
by the Alabama Agricultural Experi-
ment Station (AAES). The new
series is meant to promote timely
reporting of research results deal-
ing with a specific crop or commod-
ity, with distribution to all producers
of that particular commodity. In this
case, the target audience is all Ala-
bama poultry producers.
Today's highly competitive
conditions make it doubly important
that agricultural producers have
available the latest scientific infor-
mation. Publication of this new
series is meant to help meet that
need. Efforts will be made to
maintain up-to-date mailing lists of
each producer group so all Alabama
producers will receive the appropri-
ate report annually.
For more information about
poultry production and the latest
recommendations, please contact
your county Extension Service
office.
L ow Fat Feeds Reduce
Leg Problems in Heavy
Broilers
High performance feeds that
contain high fat levels support
maximum rate of gain. However,
such feeds also increase bird losses
caused by leg problems.
Omitting added fat from the
feed and balancing nutrients at a
reduced level have been advocated
to relieve these losses. This approach
has not been adopted commercially,
however, because of the perceived
threat of reduced growth, poorer
feed conversion, and possible loss in
meat yield.
An AAES experiment exam-
ined the effects of low fat feed on
broiler males reared to 8 weeks of
age. The feeds contained corn and
soybean meal, adjusted to maintain
a proper balance between protein
and energy when the fat was re-
moved.
Omitting fat from the starter
ration led to a reduction in body
weightby 3 weeks of age, along
with poorer feed conversion. Ex-
amining the bones of the leg with
an imaging device indicated that
impending leg problems (i.e., tibial
dyschondroplasia) were not as ap-
parent with fat omitted from the
feed. During the two subsequent 3-
week periods, feed conversion con-
tinued to be high, as shown by data
in the table. However, the difference
in body weight between treatments
disappeared and the bone structure
advantage from omitted fat contin-
ued.
All birds were processed, and
various aspects of yield were meas-
ured. Yield of whole chilled car-
casses was not affected by the die-
tary treatments. Each carcass was
deboned utilizing standard commer-
cial cuts. The proportion of parts
and meat from the breast and thigh
was similar, regardless of fat inclu-
sion or exclusion from the feed.
Overall results indicate that
flocks intended for heavy weights
Performance of Broiler Males Given High and Low Fat
Feed 0-3 weeks 3-6 weeks 6-8 weeks Total
fat BW
1 
F/G
2 
%TD
3  
BW F/G %TD BW F/G %TD F/G
High..... 1.80 1.69 8.0 5.06 2.15 30.6 6.85 2.65 27.4 2.16
Low..... 1.67 1.81 1.2 4.77 2.32 12.4 6.86 2.60 17.5 2.28
BW = body weight in pounds.
2 Pounds of feed per pound of gain.
3 Percentage tibial dyschondroplasia.
AABAMA AGRICULTURAL EXPERIMENT STATION AuBuRN UNIVERSITY
LOWELL T. FROBISH, DIRECTOR AUBURN UNIVERSITY, ALABAMA
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and deboning for breast and thigh
meat benefit from omitting fat from
the feed. Final weight gain is not
affected, while the potential for leg
problems is reduced. Unavoidably,
feed conversion suffers. However,
since added fat is expensive, cost of
gain should decrease.
E.T. Moran, Jr., S.F. Bilgili,
G.R. McDaniel, and J.E. Bartels
Proper Feed and Water
Withdrawal Improves
Processing Efficiency
Itis a common practice to with-
draw feed and water from market
age broilers priorto processing. This
fasting period not only saves feed
but, more importantly, allows emp-
tying of the digestive system and
facilitates automated evisceration in
the processing plant.
Broilerprocessors occasionally
observe a high incidence of gastro-
intestinal fragility (i.e., easily bro-
ken and torn stomachs and intes-
tines) during evisceration. Usually
this fragility maybe explained by in-
testinal diseases (such as coccidiosis
and enteritis) or mycotoxicosis.
Recent AAES research indi-
cates that duration of feed with-
drawal and sex of broilers can also
have an impact on gastrointestinal
breaking strength. Breaking strength
measurements were made on sev-
Better Fowl Cholera Vaccine
The incidence of fowl cholera
in Alabama and in the Southeast has
increased in recent years. Many of
the flocks with cholera had beenpre-
viously vaccinated with attenuated
vaccine strains of Pasteurella sp., a
procedure thought to be easy and
inexpensive. The contagiousness
and resistance of the vaccine strains
were evidenced by the development
of cholera in birds 8-12 weeks of
age, in houses where vaccinated
eral regions (stomach and gizzard
junction, stomach, duodenum, small
intestine, and colon) of the digestive
system of male and female broilers
(49 days of age) that had been sub-
jectedtovariousfeedandwaterwith-
drawal treatments. The treatments
included 0, 6,12,18, and 24 hours of
feed withdrawal, with and without
simultaneous water withdrawal.
Tissue moisture levels were also
measured during the experiment.
In general, digestive systems
full of ingesta (0 hours feed with-
drawal) had the lowest shear values,
indicating a greater likelihood of
tearing during processing. Shear
values increased with longer feed
withdrawal times. Access to water
during feed withdrawal did not af-
fect the fragility. Overall, shear val-
ues were higher for males than
females.
During feed withdrawal, tis-
sue moisture levels were lower at 6
and 24 hours as compared to 12 and
18 hours. This observation supports
the general hypothesis that feed
withdrawal more than 12 hours
before slaughter oftenresultsinmore
liquid digestive contents and en-
hances fecal contamination rate in
the plant.
These results suggest that
properly managed feed and water
withdrawal programs can mini-
mize the likelihood of intestinal
breakage and fecal contamination
during commercial processing of
broilers.
S.F. Bilgili
Needed in Alabama
chickens had previously been
housed. Conventional techniques
of cleaning houses between flocks
have not reduced the Pasteurella con-
tamination.
AAES studies were made to
determine the role of the attenuated
vaccine in the dissemination of fowl
cholera. Eight-week-oldbroiler-type
chickens were vaccinated in the wing
web with a commercially available
attenuated live fowl cholera vaccine.
Nodulesdevelopedinthevaccinated
wing web 5 days postvaccination,
and by 15 days, 12 percent of the
chickens died with symptoms com-
patible with fowl cholera. Bacterio-
logical isolation of Pasteurella sp. con-
firmed the diagnosis.
Three weeks postvaccination,
50 percentof the chickenswere show-
ing signs of sickness, including diar-
rhea, recumbent position, ruffled
feathers, loss of appetite, and weight
loss. Some of the vaccinates had
enlargement of the wing joint adja-
cent to the site of vaccination, and
cyanosis of the skin on the area over
the shoulder joint.
Necropsy examination of sick
chickens revealed that 30 percent
had lesions characteristic of fowl
cholera. The spleens were enlarged
and often had white nodules. The
livers were enlarged, congested,firm
in consistency, and often contained
small white spots. Lungs were al-
ways enlarged and edematous and
had areas of hemorrhages. The kid-
neys were extremely enlarged and
congested and showed multiple
whitish focal areas. Chalky material
was often found in the kidney area
resembling gout. All remaining
chickens were necropsied 35 days
postvaccination, and Pasteurella of
the vaccine serotype was isolated
from 20 percent.
The data obtained in these
studies show that the vaccine strains
of attenuated Pasteurella have re-
tained a degree of virulence that can
result in field problems. In order to
induce immunity, the vaccine strain
must have a minimum level of viru-
lence to reproduce within the chicken
and to maintain the necessary inva-
siveness to make contact with the
immunological system. During the
process of reproduction and inva-
siveness, it is apparent that some of
the bacteria revert to a higher degree
of virulence and this results in infec-
tion of chickens.
These resultsclearlyexplain
the spread of cholera following vac-
cination with attenuated vaccines,
and especially the outbreaks that
occur during stressful periods such
as the beginning of the laying cycle.
I . . . I
Y~~UI\ULL UILU 1~~~~ ~VILLLUIUILHLIVII
Because the vaccine strain serotype
is also isolated from very young
chicks, it appears that the vaccine
strain is hardier than conventional
strains of Pasteurella.
It is apparent that new and
better vaccine formulations are
Matching Vaccine to Virus
Controlling IBDV
Despite advances in vaccine
development and antibody deter-
mination, infectious bursal disease
virus (IBDV) incidence and associ-
ated disease problems still occur. In-
fection with IBDV in young chick-
ens produces atrophy of the bursae
of Fabricius and immunodepression.
Immunodepressive IBDV infections
appear with increased frequency and
severitydespite improved sanitation
and hygiene and repeated IBDV
vaccination. Immunodepression
decreases vaccine efficacy and in-
creases susceptibility of chickens to
other infectious agents. One cause
of increased IBD may be the varied
subtypes of the virus that causes the
disease.
The objective of this AAES
study was to determine how three
IBD vaccines protectbroilersagainst
infection with serological subtypes
of IBDV. This study was the first to
examine the efficacy of new live
IBDV subtype vaccines against stan-
dard and variant serologic IBDV
isolates, thus generatinginformation
for more effective control of IBD.
Specific pathogen-free (SPF) broil-
ers were used in the study.
The efficacy of live vaccines
against IBDV subtypes was deter-
mined using 16 groups of 20 broilers
per group. The design consisted of
three vaccine groups and a nonvac-
cinated (NV) group, each of which
was challenged with one of three
IBDV isolates. In addition, there
was a non IBDV challenge group for
each of the three vaccinated groups.
needed by the poultry industry.
The emulsified vaccines induce a
good antibody response but they can
also induce unacceptable side reac-
tions such as arthritis.
E.C. Mora
Subtype Important in
The challenge isolates were the
Delmarva variant E, a standard se-
rotype 1 (APHIS), and an untyped
virulent isolate from Mississippi.
The vaccines were a cloned stan-
dard (CS) vaccine (Clone Vac-D78),
a cloned variant (CV) vaccine (Bursa
Vac IV), and a noncloned standard
(NCS) vaccine (Bursine II). Vaccina-
tion was at 10 days, challenge at 24
days, and necropsy examination at
31 days. A protection score (per-
cent) was calculated for each group
based on the percent of birds with
normal size bursae of Fabricius.
Results showed an average percent
protection score against all three
challenge viruses for the CS vaccine
of 63, the CV vaccine of 68, and the
NCS vaccine of 75.
Results indicated efficacy dif-
ferences among the three vaccines
against the three challenge viruses.
Although theNCS vaccine provided
the highest overall protectionagainst
the three IBDV, differences were
small when compared to the other
two vaccines. However, significant
differences were evident in protec-
tion scores of each of the three vac-
cines against individual challenge
viruses. Therefore, it is important to
determine the predominant IBDV
subtype in the field before selecting
the vaccine to use. Results reported
herein provide a rationale for select-
ing efficacious vaccine programs in
breeders and broilers once the domi-
nant IBDV subtype in an area, com-
plex, or farm is established.
J.J. Giambrone
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Early Detection of TD Cuts
Broiler-Breeder Losses
Tibial dyschondroplasia (TD)
is a common skeletal abnormality in
rapidly growing broilers and tur-
keys. Though not fatal, TD causes
lameness and interferes with birds
getting food and water. The end
result is reduced efficiency or even
death due to starvation and/or de-
hydration. TD costs poultry pro-
ducers millions of dollars annually
in replacementbirds and much more
in poor performance of surviving
birds.
The incidence of TD was stud-
ied in broiler breeders reared under
two nutritional-management regi-
mens at the AAES:
0 Regimen 1. From 0 to 8
weeks of age, both males and fe-
males were fed free choice a broiler
diet similar to the one used by basic
breeders (23 percent protein, 3,200
ME/kg). At 8 weeks the birds were
changed to a developer diet of 18
percent protein and 2,900 ME/kg
and placed on a restricted feeding
program for the duration of the ex-
periment. The amount of feed fed
from 8 to 20 weeks of age was de-
termined by the weight the birds
needed to achieve breeder recom-
mended body weight by 20 weeks
of age.
* Regimen 2. The same num-
ber of birds as in regimen 1 were fed
the same developer diet free choice
from 0 to 3 weeks. Then, regulated
amounts of feed were supplied from
3 to 20 weeks.
TD was determined on the legs
of the broiler breeders at 4, 7, 11,
and 15 weeks of age using a Lixis-
cope (imaging device). The percent-
age incidence for male birds in regi-
men 1 at these ages was 14, 20, 9,
and 0 percent, respectively. Only 2
percent of the females at 7 weeks of
age developed TD. None of the
birds in regimen 2 developed TD.
Peak incidence of TD occurred at 7
weeks of age; at 15 weeks of age
none of the birds showed symp-
toms of the disease.
I I
Though TD cannot be pre-
vented by any known nutrients and
reduced growth rate due to reduced
feeding is not acceptable, the AAES
study demonstrates that the disease
can be detected early by using a
Lixiscope. This will allow basic
breeders to cull affected birds and
reduce the incidence of TDby choos-
ing only unaffected birds for their
breeding programs.
J. Wong-Valle, G.R. McDaniel,
and J.E. Bartels
Dried Whey in
Withdrawal Feed
Ineffective Against Broiler
Salmonellae
The percentage of broilers har-
boring Salmonellae has been shown
to greatly increase during live haul.
This rapid cross-contamination can
largely be attributed to fasting prior
to catching, close contact in transit,
C ell Surface Molecules
Affect Productivity of
Chickens
As in all animals, cell surface
molecules of chickens produced by
the major histocompatibility com-
plex (MHC) act as self-identification
agents by which the species recog-
nizes foreign substances. This mo-
lecular recognition is the essential
step by which the cells of individu-
als generate immunity against for-
eign invaders.
Recent work on commercial
broilers aided by well-studied lines
of chickens maintained in the Au-
burn Avian Immunogenetic Model
(AAIM) reveals three new facts
about the MHC genes:
1. Mutation is unusually high
in one of the world's fastest growing
and consumption of contaminated
cecal droppings.
Since access to feed may influ-
ence retentionof consumed Salmonel-
lae, initial research examined the sig-
nificance of feed intake, before and
after cooping, on the Salmonellae
problem. Results indicated that
feeding and fasting would influence
the numbers of cells in the ceca at the
expected time of processing. How-
ever, the differences were small and
threats to carcass cross-contamina-
tion would continue to be substan-
tial.
Reducing the extent of Sal-
monellae shedding prior to cooping
would reduce subsequent contami-
nation. Lactose in the feed is known
to alter the cecal microbial popula-
tion, increase the organic acid level
of the contents, and reduce the pH.
These changes are unfavorable to
Salmonellae and can cause meaning-
fulreductionsintheir concentrations.
Dried whey is high in lactose, but its
use is limited because of its cost and
the adverse effects on performance.
However, use of low concentrations
of whey in the withdrawal feed was
a possible option.
broiler breeder lines and the struc-
ture of the MHC genes of chickens is
more complex than previously
shown. Selection for rapid growth
apparently accelerates mutation.
2. Rapid growth modifies the
effect of MHC genes on the inci-
dence of signs and symptoms of
Marek's disease (MD); therefore, the
effect of a certain MHC gene on a
Leghorn x broiler cross is not the
same as that in a purebred
broilerline, 
see table. Thus, 
E
the MHC genes do not act
independently of other
genes in the species.
3. MHC genes caus- MHC g
ing high susceptibility to
the growth of the tumors
of MD, in contrast to those
causing resistance, pro- SR
duce faster body growth 'Sex
in broilers. 2 R MI
The AAES 
results previous
A study at the AAES evaluated
the addition of dried whey to with-
drawal feed and its ability to reduce
cecal Salmonellae after an oral dose of
organisms. A probiotic providing
an array of microbes compatiblewith
the ceca was included 
to augment
fermentation.
Live performance was not af-
fected by either of the feed additives
or a combination of the two. The
ceca were significantly affected 
(in-
creased weight and expansion from
entrapped gas) whenever 
whey had
been incorporated in the feed, indi-
cating that conditions unfavorable
to Salmonellae had been induced.
However, recovery of Salmonellae
was similar, regardless of treatment.
Based on these results, dried
whey in withdrawal feed is consid-
ered ineffective in Salmonellae con-
trol because little relief from cross-
contamination canbe expected. 
The
increased cecal size created by whey
is undesirable because of the 
in-
creased likelihood of gut 
breakage
during evisceration.
E.T. Moran, Jr.
and S.F. Bilgili
show that MHC genes modulate and
are modulated by the expression of
other genes, identifying apparentre-
ciprocating feedback loops with
large effects on productionefficiency.
The germ plasm resources in AAIM
enable similar exploration of pro-
ductivity through basic biological
science into the future.
L.W. Johnson
ffect of MHC Gene on MD Incidence and
Broiler Growth'
MD incidence
ene
2  
oi Leghorn7-week body
Broiler Leghorn weight
cross
Pct. Pct. Lb.
MD 71 34 4.11
MD 73 90 4.40
es pooled.
D = resistant to MD and S MD = susceptible to MD as
ly proved in purebred Leghorns.
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Large Particle Limestone
Improves Calcium
Solubilization
by Laying Hens
It has been hypothesized for
several years that laying hens solu-
bilize a higherpercentage of ingested
calcium from large particlelimestone
(LPL) than from small particle lime-
stone (SPL). However, there was no
scientific evidence to support this
hypothesis until AAES experiments
comparing the percentage of LPL
and SPL calcium solubilized by lay-
ing hens proved this theory was true.
Solubilization of calcium from
limestone is important because only
the solubilized form is available for
absorption in the digestive system
of the hen. Increased solubilization
of limestone by the hen means in-
creased availability of calcium for
the hen to absorb and to subsequently
use in egg shell formation.
During the studies, 3.75 g
(grams) of SPL and LPL were intu-
bated to two groups of laying hens.
Solubilization and retention of cal-
cium by hens were measured be-
tween two consecutive ovipositions
(24-26 hours). The LPL used in the
study was 2-5 mm (millimeters) in
diameter (pullet size) and SPL was
0.5-0.8 mm in diameter (fine granu-
lar).
More calcium was solubilized
and retained in the body of the hen
from LPL than from SPL, as shown
in the table. The hens consuming
LPL solubilized approximately 0.5-
0.8 g more than the hens consuming
SPL. These results indicate that it is
beneficial to substitute a large par-
ticle calcium supplement, such as
pullet-size limestone or oyster shell,
for a part of the fine granular lime-
stone used in the diet. Using large
particle supplements in the laying
hen diet decreases calcium solubili-
zation from limestone and increases
its availability for absorption by the
hen.
K.S. Rao and
D.A. Roland, Sr.
Delaying Change from Pullet Feed to Higher Calcium
Layer Feed Reduces Performance of Hens
Many egg producers have de-
layed the transition from pullet to
layer feed or have fed diets contain-
ing an intermediate level of calcium
until the average production of the
flock was 5 percent. The justification
for this method of feeding was that if
layer calcium levels are fed too early,
the higher calcium levels will sig-
nificantly reduce feed consumption
and adversely affect egg produc-
tion. No data have been found
which indicate that increasing
feed intakeby feeding inadequate
calcium will have any overall
benefit on hen performance.
However, there are data to indi-
cate that incorrect timing of the
transition from pullet to layer
feed and feeding incorrect cal-
cium levels will adversely affect hen
performance.
Results of AAES experiments
indicated that delaying the transi-
tion from pullet to layer feed until
pullets had laid just 7 eggs increased
feed consumption. 
The overcon-
sumption had no beneficial effect on
egg size, but the calcium deficiency
did reduce egg specific gravity and
bone strength. It was concluded that
feeding early maturing pullets layer
calcium levels did not reduce feed
intake but that early maturing pul-
lets fed inadequate calcium over-
consumed in an attempt to obtain
more calcium.
When the transition from pul-
let to layer feed was delayed until
production was approximately 10-
15 percent, pullets consumed an
average of 5 percent more feed and
were 5 percent heavier at the end of
the production cycle than pullets fed
layer calcium levels starting at 2
weeks prior to the first egg. The in-
creased feed consumption had no
beneficial influence on egg produc-
tion or egg size but did significantly
reduce feed efficiency.
The study illustrated the im-
portance of properly timing the tran-
sition frompulletto layer feed. Delay
in providing the correct quantity of
calcium to early maturing pullets
will increase feed consumption, body
weight, and liver fat, and will reduce
egg shell quality, bone strength, and
feed efficiency. The increase in feed
intake will not increase egg size but
will increase feed cost. Hens should
receive the correct calcium level ap-
proximately 10 to 14 days prior to
the first egg and not after the first
egg.
D. A. Roland, Sr.
Effect of Dietary Limestone Particle Size on
Calcium (Ca) Solubilization in Laying Hens
Ca available, Particle Ca solubilized Ca retained
grams size by the hen by the hen
Grams' Pct. Grams Pct.
Trial 1
3.46 .......................... Large 2.75 79 2.54 73
3.75 ......................... Small 2.18 58 1.94 52
Difference .... .............. 57 .60
Trial 2
3.33....................... Large 2.79 84 2.26 68
3.75 ......................... Small 2.03 54 1.94 52
Difference ................. 76 .32
S1 ounce = 28 grams.
Effects of Pre-production Levels of
Calcium Feeding on Performance of
Hens for 12 Months
Calcium level fed, pct. Feed Bod
2  
consumption/ 
Bodt
Pullets Hens
2  
hen/day weig
Grams Lb.
1.0 3.75 115 4.0
1.7 3.75 113 4.1
3.7 3.75 110 3.8
'Fed until 15 percent production reached.
2 Fed for 12 months after 15 percent production reached.
I I
ill
Mature and Immature
Pullets Compared at
Sexual Maturity
Age at sexual maturity (pro-
duction of first egg) is influenced
by genetic background and envir-
onment. Stimulation of hormone
events required for egg production
may have threshold requirements of
age, body weight, and/or composi-
tion (e.g., fat and protein). To deter-
mine these requirements, differences
between immature and mature
broiler breeder pullets were exam-
ined in AAES research.
Pullets were raised on litter
floors under standard management
procedures and placed in cages at 18
weeks of age. The lighting schedule
was: 23 hours light (L), 1 hour dark
(D) at 1-day-old; 8 hours L, 16 hours
D thereafter to 17 weeks; 9 hours L,
15 hours D from 18 to 19 weeks; and
S upport Poultry Research
Funds appropriated by the
Alabama legislature provide the
major financial support for Ala-
bama Agricultural Experiment Sta-
tion research. Hatch funds from the
U.S. Government also represent an
important funding source. Since
these funds are limited, however,
EDITOR'S NOTE
Mention 
of company 
ortradenames
does not indicate endorsement by the Ala-
bama Agricultural Experiment Station or
Auburn University of one brand over an-
other. Any mention of non-label uses or
applications other than labeled rates of pes-
ticides or other chemicals does not consti-
tute a recommendation. Such use in re-
search is simply part of the scientific inves-
tigation necessary to fully evaluate materi-
als and treatments.
Information contained herein is
available to all persons without regard to
race, color, sex, or national origin.
June 1989 6M
Body and Organ Weights at Sexual Maturity
VariableResult, 
by pullet maturity
Variable
Immature Mature
Body weight, Ib.. ....... 5.3 6.1
Abdominal fat pad, grams'...... 52.1 80.2
Liver, grams........ .. ......... 56.7 83.9
Ovary, grams ........................ 1.5 45.4
Oviduct, grams ... ........... 6.8 98.9
Carcass with fat pad
Fat, pct ................................ 15.1 17.1
Protein, pct ........... .............. 17.0 16.5
Liver
Fat, pct .............................. 20.6 19.0
Protein, pct ........................ 17.1 15.9
11 ounce = 28 grams.
15 hours L, 9 hours D from 20 weeks
to end of experiment.
At production of the first egg,
weights were taken of the egg, body,
liver, ovary, oviduct, and abdomi-
nal fat pad from mature pullets. Fat
and protein contents of the carcass
(including fat pad) and liver were
determined. Similar measurements
were made in paired immature pul-
lets which lacked rapidly growing
follicles.
many areas of research would go
unsupported except for financial
support from various granting agen-
cies, commodity groups, and other
friends of the Experiment Station.
Contributions of these supporters to
the AAES programs of research are
acknowledged with gratitude.
Among these supporters of
AAES research, the following are
thanked for their contributions to
"Alabm Agricututal xeien tto
Auburn... University...Alaaa38902
Average age at pro-
ductionoffirsteggwas 178
days. As shown by data in
the table, live body weight
and weights of the liver,
ovary, and oviduct were
greater in mature than
immature pullets. How-
ever, differences in body
weightbetween immature
and mature pullets were
accounted for by weights
of the reproductive organs
(e.g., egg, ovary, and ovi-
duct) of the mature birds.
There were no differences in carcass
fat orproteinbetween immature and
mature pullets. Livers of immature
pullets had a greater percentage of
fat than those of mature pullets.
With sexual maturity delayed
by restrictive photoschedules in this
research, results did not identifyany
strict thresholds for body weight and
composition for production of the
first egg.
J.A. Renden
1988-89 research in poultry science:
* Agri-Bio Corp.
* Alabama Poultry & Egg Assoc.
* American Cyanamid Co.
* Ethyl Corp.
0 Hoechst-Roussel (Agri-Vet Div.)
* Hoffman-LaRoche
* Ross Breeders, Inc.
0 Southeastern Poultry & Egg Assoc.
* UpJohn Co.
0 USDA/ARS
NON.... PROFIT.............
.... ... .... ... .... E S. ...A I ..
PERMIT...... No........
AUBURN...... A.. .....
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