KESEARCH UPDATE
1992
POULTRY
Evaluation of Spreader Distribution
Patterns for Poultry Litter
After poultry litter is spread on of 26 percent for the smallest size frac-
pasture land, light green streaks often tion to 43 percent for the largest. The N
are noticed in the grass, indicating an concentration varied randomly from
uneven nutrient distribution across the 3.2 percent to 4.3 percent for the differ-
field. An Alabama Agricultural Ex- ent size fractions, however, giving no
periment Station study indicates this indication of higher manure concentra-
unevenness is caused by nonuniform tions for the smaller size particles. Ac-
distribution across the spreader swath cordingly, the average N concentration
rather than inconsistent nutrient con- in the pans spaced across the swath was
tents in the litter, relatively constant.
For the study, a pull-type spreader The weight of litter collected in the
distributing poultry litter was driven pans was used to calculate application
over the center of a set of evenly spaced rates and to determine distribution
collection pans. Samples from each uniformity for different travel spac-
pan were weighed and sieved into ings (swath widths) with the spreader.
different particle size fractions to deter- Uniformity was best at a swath width
mine the distribution of particle sizes of 28 feet, and decreased as the swath
across the swath. The sieve fractions width increased to40 feet. Theapplica-
from each pan were analyzed to deter- tion rate at a 28-foot spacing was 1.39
mine nitrogen (N) and carbon (C) con- tons per acre.
centrations for each pan sample. Poul- The operator's manual for the
try litter samples also were collected on spreader recommended a 40-foot
a tarp spread across the swath, and swath width and indicated an applica-
these samples were used to determine tion rate of 1.3 tons per acre for the
N and C concentrations for each sieve spreader gate setting and bulk density
fraction. of litter used in this test. At a 40-foot
Particle size distribution data from spacing, the application uniformity in
the samples collected from the pans this test was very poor and the appli-
showed that the smaller-size material cation rate was less than 1 ton per acre.
landed closer to the center of the swath. These results suggest that 
travel spac-
Laboratory analysis of the different par- ings used when spreading poultry lit-
ticle size fractions showed a consistent ter may need to be lower than 
the
increase in C concentration with in- manufacturer's recommendation.
creased particle size, from an average J.H. Wilhoit. C.W. 
Wood. and K.H.Yoo
Ensiling
Johnsongrass with
Broiler Litter
Shows Potential as
an Alternative
Feedstuff
With approximately 2 million
tons of broiler litter being produced
each year in Alabama alone, creative
uses of this resource are constantly
being sought. An Alabama Agricul-
tural Experiment Station study has
shown that broiler litter can be ensiled
with johnsongrass, turning two po-
tentially troublesome resources into
palatable, good quality feed for live-
stock.
For the study, johnsongrass/
broiler litter silage and a corn/broiler
litter silage were used. Johnsongrass
was harvested in early June at 65 per-
cent moisture and ensiled with 10 or
20 percent added broiler litter. Corn
was harvested in late July and ensiled
with broiler litter added at 10 or 20'%.
In mid-September, the silages were
fed to growing lambs.
The addition of broiler litter in-
creased the crude protein content and
the mineral content in the four silages.
All four silages were readily consumed
when offered to the lambs. Johnson-
grass silage was not equivalent to
continued on page 2
AUBAMA AYy~ifCg1[4' EXPER4'IENT STATON A N KUN~IVES ITY
Pre-Slaughter Stunning Current Affects
Carcass Quality of Broilers
Downgrading of broiler carcasses due to trims, broken bones, bruises, and
hemorrhages causes tremendous economic loss to the broiler industry in the United
States. Carcass quality of broilers can be optimized by defining and monitoring
critical stages in live-production and processing phases. However, little information
is available on the effects of various rates of pre-slaughter electrical stunning
currents on carcass quality attributes of broilers and possible interactions due to
strain-cross (SC) differences.
In a recent Alabama Agricultural Experiment Station study, 50-day-old male
broilers from two SCs (6 replicate pens per SC; 30 broilers per pen) were
individually stunned in a brine-bath stunner using a rectangular wave DC current
(50 percent duty cycle, 100-Hertz frequency). Stunning current levels consisted
i of 25, 45, and 70 milliamperes (mA) per broiler. Following standard processing
procedures, all carcasses were chilled and individually evaluated for the inci-
dence of broken bones and hemorrhages.
Carcass quality attributes did not differ significantly between the SC used.
However, a significant interaction was observed between SC and stunning current
level for hemorrhages on wings. Incidence of broken clavicles (wishbones) more
than doubled with each increase in stunning current. In contrast, broken wings
increased linearly and hock bruises decreased linearly as current increased. Other
carcass defects frequently attributed to stunning, such as engorged wing veins, red
tail, or red feather tracts, were not affected by the current levels used in this study.
These results suggest that SCs used and quality characteristics of the end
products should be considered when selecting pre-slaughter stunning current.
Results further indicate that operating conditions of stunners at commercial
Sprocessing plants (electrical current type, level, duration, and conductiv-
S'ity of the brine solutions) should be determined and closely monitored for
optimum processing efficiency and product quality.
S.F. Bilgili
Male Broiler
Breeders Part of
Salmonella Puzzle
Although proper food handling re-
mains the best means for preventing
foodbomrne disease, there are other op-
portunities during the live production
of food animals for improving the
safety of food products derived from
these animals. Thus, research identify-
ing points of entry of Salmonella dur-
ing the live production phase has re-
cently intensified.
Previous research has found that at
the time of hatch, broiler chicks may be
infected with salmonellae, indicating
that live production management prac-
tices are crucial for the control of Sal-
monella. Hens have been indentified
as a potential harborage of Salmonella.
However, it is also important to evalu-
ate the role of the male in Salmonella
spread because, in commercial set-
tings, one male can breed a large num-
ber of females. This was investigated
in a recent Alabama Agricultural Ex-
periment Station study.
Hens were artificially inseminated
continued on page 3
Composting, Fermentation Show Promise for Dead
Poultry Disposal
Every broiler production facility
is faced with the reality of disposing of
dead birds. Due to increasing burial or
incineration costs and concern for forth-
coming environmental issues and
regulations, alternative methods of
disposal are needed.
Composting poultry carcasses is
one environmentally safe disposal
method that can be utilized. During
composting, organic wastes are de-
composed by naturally occurring or-
ganisms into a product that can be
used as a fertilizer.
Results of Alabama Agricultural
Experiment Station (AAES) studies
indicate that coliform bacteria and en-
teric pathogens, such as Salmonella,
are inactivated by heat generated dur-
ing a typical two-stage composting
cycle. These results suggest that
composting is a viable, environmen-
tally sound, and safe way to dispose of
dead poultry.
Another use for dead poultry is to
render the carcasses into a valuable
protein meal. However, the spread of
avian and human disease while trans-
porting dead birds to a rendering facil-
ity is a concern. Fermentation, a natural
process that allows anaerobic microor-
ganisms to reduce and stabilize organic
materials, is an option for stabilized,
pathogen-free storage of carcasses.
Preliminary AAES research on this
subject indicates that long-term fer-
mentation of poultry carcasses (5-10
weeks or more) is possible and that
pathogenic microorganisms, 
such as
Salmonella, are inactivated during the
process. Such laboratory findings sug-
gest that fermentation holds promise
as an alternative method for the
biosecure on-farm storage of poultry
carcasses in the future.
J.P. Blake, D.E. Conner, and J.O. Donald
Johnsongrass, continued
corn silage; however, johnsongrass
still produced acceptable digestibilities
and was palatable.
The johnsongrass silages were ad-
equate in crude protein content for all
types of cattle, though energy contents
were low. However, johnsongrass si-
lages would be nutritionally adequate
as a feed for brood cows early in their
pregnancies.
B.J. Rude and D.L. Rankins, Jr.
I
r . r r . I 1 mi 1
Salmonella Puzzle, continued
with 0.05 ml of test semen and, during
a 14-day period, eggs were collected
and sampled for salmonellae. At the
end of 14 days the ovary and oviduct
were sampled for the test strains of Sal-
monella.
Results showed that the ovaries
and all parts of the oviduct can be
infected via semen, and that the patho-
gen can persist in the hen's reproduc-
tive tract for up to 14 days. Of the eggs
sampled, only shell samples tested
positive for Salmonella contamination,
suggesting no transovarian transmis-
sion occurred since no internal compo-
nents were infected. However, sur-
face contamination of these eggs may
contribute to the spread of salmonellae
in the hatchery.
Based on these data, it appears
that the male may play a role in con-
taminating the reproductive tract of
the hen, thus continuing the cycle of
Salmonella transmission. However, the
hens in this study did not consistently
produce infected eggs, illustrating the
complex nature of Salmonella spread
and control in live poultry.
Nevertheless, male birds and re-
lated breeding activity are critical
points at which intervention may be
effective for controlling Salmonella
contamination of final food products.
Thus, any additional reduction in Sal-
monella numbers at the breeder and
hatchery levels that results from use of
Salmonella-free breeders, additional
sanitation, egg disinfection, etc., would
likely help improve the microbiologi-
cal safety and quality of poultry prod-
ucts at the retail level.
M.A. Reiber and D.E. Conner
Vitamin C Improved Egg Shell Quality
in Old Layers
The use of vitamin C (ascorbic
acid) in chicken rations has been
controversialbecause chickens can pro-
duce vitamin C in the body and it is
assumed that they do not need an exter-
nal supply. However, recent studies
have shown that supplementation of
vitamin C in chicken rations or drink-
ing water improves the overall perfor-
mance of chickens, especially during
heat stress.
In laying hens, the ability to absorb
intestinal calcium needed for egg shell
formation is reduced as hens age. A
recent Alabama Agricultural Experi-
ment Station study was conducted to
determine if vitamin C would improve
egg shell quality in old layers. Results
of the study indicate that feeding vita-
min C to hens at 2,000 parts per million
(ppm) increased blood calcium, re-
sulting in increased egg weights of
up to 5 percent and improved egg
specific gravity.
The study involved two experi-
ments. In the first experiment, 100 96-
week-old white leghorn (Hyline W36)
hens were randomly divided into five
groups (five hens per group) and each
group was provided rations containing
one of four levels of vitamin C (1,1,000,
2,000, and 3,000 ppm). In the second
experiment, 384 hens (96-week-old,
Hyline W36) were divided into four
groups of 24 hens and provided a ra-
tion containing vitamin C at the same
levels used in experiment 1. Hens in
both experiments were fed the vitamin
C diets for 4 weeks. Egg weight and
specific gravity were measured weekly
and, at the end of the experimental pe-
riod, blood was collected from hens
and analyzed for total and ionic cal-
cium concentration.
Results demonstrate that feeding
vitamin C at 2,000 and 3,000 ppm re-
sulted in increased egg weight and egg
specific gravity. The improvement in
these factors might be related to vita-
min C-mediated influence on calcium
absorption. Blood calcium was higher
in hens that were fed 2,000 and 3,000
ppm ofvitamin C. These findings imply
that vitamin C enhances calcium ab-
sorption in old layers, thus making
more calcium available for deposit on
the egg shell.
If vitamin C would improve egg
J.I. Orban and D.A. Roland, Sr.
Fum onisins May
Be Toxic to
Broiler Chickens
Fumonisins are a recently discov-
ered group of mycotoxins produced by
Fusarium moniliforme and F. proliferatum
fungi that are widely distributed
saprophytes on corn and sorghum.
It is possible that fumonisins are a
common contaminant of poultry feed
that could be affecting southeastern
flocks, particularly when locally-grown
feed is used. A preliminary Alabama
Agricultural Experiment Station study
sought to evaluate the potential impact
of this fungi on poultry.
For the study, day-old commercial
broilers were fed rations containing 0,
22, or 112 parts per million (ppm) (F) B1
fumonisin (produced by F. moniliforme
on corn) in a standard Auburn Univer-
sity corn-soybean broiler starter ration.
Treatment groups, each involving 10
birds, were fed the rations for 3 con-
secutive weeks. Body weights and
feed consumption were measured
weekly for each treatment. The birds
were killed at 3 weeks of age and exam-
ined for gross lesions.
Within 3 days of consumption of
22 or 112 ppm fumonisin, broiler
chicks developed a watery diarrhea
that persisted throughout the feeding
trial. After 2 weeks of toxin consump-
tion, birds in the 22 and 112 ppm
groups produced a bright orange pig-
mented diarrhea. However, the birds
showed no other signs of morbidity
and mortality usually associated with
mycotoxin consumption throughout
the study.
The 3-week body weights and feed
consumption of birds fed fumonisin
continued on page 4
Egg Shell Quality, continued
shell quality in old layers under normal
conditions, as was the case in these ex-
periments, it is likely that it will be
even more beneficial during hot
weather. These results indicate that
producers having egg shell quality
problems should consider supple-
menting layer rations with vitamin C.
I I i1CT: T~ L \/II ~ C. TT \/ ILrT ~ r~
Delaying Photostimulation May Result in
Larger Eggs, Higher Productivity
Normally, broiler breeder replace-
ments are photostimulated at 20 weeks
of age. However, genetic changes in
conformation and growth rate have
resulted in a need to reevaluate the
timing of photostimulation because,
as growth rate has increased, feed effi-
ciency, conformation, reproduction,
and early egg size apparently have
declined.
Alabama Agricultural Experiment
Station experiments were conducted
to assess the optimum time to photo-
stimulate males and females into re-
production.
A standard lighting program of 8
hours light, 16 hours dark was used to
rear 1,200 female and 120 male birds.
Males were stimulated at either 19, 20,
21, or 22 weeks of age, and male re-
sponse at all ages of stimulation was
similar. Onset of semen production
was slightly earlier in the 19- and 20-
week males, however volume and se-
men concentration was similar.
Performance of females stimulated
at 19 and 20 weeks was inferior to those
stimulated at 21 and 22 weeks. Al-
though onset of egg production was
earlier in the 19- and 20-week groups,
egg size was smaller and peak produc-
tion was poorer than in the 21- and 22-
week groups.
These results indicate that delaying
photostimulation until 21 or 22 weeks
for females would result in larger eggs
and higher peak production.
G.R. McDaniel
An immunoassay based on a latex
particle agglutination slide test has
been developed through the Alabama
Agricultural Experiment Station for the
assay of three avian antisera against
New disease virus (NDV), infectious
bursal disease virus (IBDV), and infec-
Fumonisin, continued
rations were lower than birds that did
not receive toxin. Likewise, the 3-week
feed conversion of birds fed either level
of fumonisin was poorer than for the
birds fed toxin-free feed.
This experiment was the first to
show that low levels of fumonisin may
cause enteritis and diarrhea in broiler
chickens. Weight gains and feed con-
version also were adversely affected by
toxin consumption at this low level.
This indicates that a potential problem
does exist and appropriate procedures
can now be implemented to test for
and remove this mycotoxin from the
diets of southeastern poultry flocks.
J.J. Giambrone, R.A. Shelby, K.L. Bowen,
and F.J. Hoerr
tious bronchitis virus (IBV).
The latex-based diagnostic test
generally requires only slides and a
drop or two of reagents. The test could
be done in 2-5 minutes and does not
require professional laboratory skills
to complete. The cost is about 5 cents
per test. The virus-microbead com-
plex can be stored for 10-12 months at
40
0
F.
The method compared well with
commercial enzyme-linked immuno-
sorbent assay (ELISA) and hemagglu-
tination inhibition. The latex slide
immuno-agglutination tests had sen-
sitivities of 97.1 percent to NDV, 98
percent for IBD, and 76.1 IBV. Specific-
ity relative to the commercial ELISA
test was 98 percent for NDV, 80 per-
cent for IBD, and 89 percent for IBV.
Because of the sensitivity, specific-
ity, and reasonable cost of this test, the
system has the potential of replacing
more expensive currently used tests.
Additional avian viruses are being
tested for use in this diagnostic
assay system using microbeads.
E.G. Mora
4
Broiler
Breeder Males
Can Be Given
Feed Based
on Corn
Male chickens are known to have
low protein needs once sexual maturity
has been attained. The essential amino
acids provided by this protein are ex-
pected to correspond to the require-
ments determined for adult Leghorn
males. A feed based entirely on corn
appears very favorable for satisfying
maintenance requirements if supple-
mented with methionine, vitamins,
and minerals.
Experimentation was conducted
through the Alabama Agricultural
Experiment Staion (AAES) to compare
the industry's standard 12 percent pro-
tein feed to a feed using corn as the sole
source of protein. Breeder males of a
commercial strain were given these two
feed treatments from 22 to 68 weeks of
age. Body weight and semen produc-
tion was measured periodically. Feed
intake was restricted to 325 kcal per
bird per day to avoid excessive body
weight gain.
The corn-based feed excessively
restricted body weight gain of birds
during the first 4 weeks, causing se-
men production to suffer. Once males
were in semenproduction,performance
was equivalent to birds given the stan-
dard feed.
Submarginal performance through
the beginning of the breeder period oc-
curred because corn did not provide
sufficient balanced protein for reason-
able growth. Further studies on utiliza-
tion of protein in corn substantiated that
lysine could be supplemented to relieve
this submarginal performance. Ap-
proximately 0.45 percent added lysine
in the feed at 22 weeks, which progres-
sively decreases to zero between 30
and 35 weeks of age, overcame this
early problem in AAES research.
E.T. Moran and W.H. Revington
New Diagnostic Assay System Using
Microbeads Developed
Lighting Programs for Broilers
Chickens used for production of
meat are genetically selected for rapid
growth and heavy body weight. These
birds commonly develop problemswith
their circulatory and skeletal systems,
and may have excessive abdominal fat.
Manipulation of the lighting program
by reducing the total hours of light or
applying intermittent schedules has
been reported to alleviate the incidence
or severity of circulatory and leg disor-
ders with slight or no lossofbodyweight
at marketing.
An Alabama Agricultural Experi-
ment Station (AAES) study was con-
ducted to compare the effectiveness of
restricted light or increasing light with
near-continuous light for male broilers.
The four light treatments are shown in
table 1. Standard management proce-
dures were followed and daily mortal-
ity, weekly body weight, and cumula-
tive feed efficiency measurements
were taken. The birds were processed
at 49 days of age.
The incidence of general leg prob-
lems and tibial dyschondroplasia were
recorded, and carcasses were scored
for quality (bruises, scratches, tears,
blisters, broken bones). Prechilled and
chilled carcasses, abdomi- days
nal leaf fat, wings, drum-
sticks, thighs, 
tenders,and 
4 ..................
fillets were weighed. 
14 ................
The 16-hour,14-hour, 21................
and increasing light 28......
treatments resulted in 49................
lower mortality than the
23-hour light treatment TABLE 2. CAR
(3.0, 3.5, and 3.5 versus
9.0 percent, respectively).
Body weight at 48 days
was not different among Variable
the 23-hour, 16-hour, 
14- Prechilled car
hour, andincreasinglight Chilled carcas
treatments (6.45, 6.42, 
Abdominal l
6.28, and 6.36 pounds, re- Wings, Ib ....
spectively). Drumsticks, Ib
Weights of the car- 
Thighs, Ib.....
cass and parts are 
shown Tenders, 
Ib....
in table 2. 
Weights of 
the Fillet, 
lb.
breast meat 
(tenders and 
Lean carca
fillets) was greater in the
23-hour group than in the other treat-
ments. Feed efficiency and incidence of
leg problems were not different among
the light treatments in this study.
The broiler industry can make eco-
nomic decisions concerning the pos-
sible loss of yield versus the improved
Age,
Feeding and Lighting Programs Influence Early Egg
Production of Broiler Breeders
Broiler breeders are often reared
under restricted feeding regimes and
short daylength lighting programs. At
the end of the rearing period, reproduc-
tion is stimulated by photostimulation
(PS) with long daylengths, causing
birds to begin producing adequately
sized eggs at about 26 weeks of age.
Since feed restriction inhibits matu-
ration, it may delay the onset of lay,
which can contribute to increased rear-
ing costs. Feed restriction also can re-
duce egg size, which is especially un-
desirable in young breeders that typi-
cally produce small eggs.
Rearing costs may be reduced by
stimulating lay at an earlier age. How-
ever, rearing period feeding programs
would need modification to allow for
earlier maturation and to compensate
for the reduced egg size of younger
birds. A recent Alabama Agricul-
tural Experiment Station study inves-
tigated the possibility of stimulating
earlier production of adequately sized
eggs by allowing greater body
weights during rearing and by initiat-
ing PS at earlier ages.
Female breeders were provided
different amounts of feed during rear-
ing and PS at different ages. Prior to
PS, the birds were provided short
daylengths and either heavy feeding
(free choice), medium feeding (to result
in projected weight of 6.2 pounds), or
light feeding (projected weight of 5.3
pounds) at 20 weeks. Pullets from each
feeding treatment were subjected to PS
by long daylengths from 14, 17, or 20,
through 64 weeks.
All treatments were provided the
same feeding program following PS. A
breeder diet was provided daily at lev-
els of 22, 24, 26.5, and 30 pounds per
100 birds during weeks 1, 2, 3, and 4
after PS, and 33,32, and 31 pounds per
100 birds during the 10-, 9-, and 9-
week periods, respectively. During the
remainder of the study, 30 pounds of
feed per 100 birds was provided daily.
Heavy pullets weighed 6.6, 7.4,
and 8.3 pounds when subjected to PS
at 14,17, or 20 weeks, respectively. Age
at first egg was earlier in hens subjected
to PS at both 14 and 17 weeks. But,
since peak production was greater in
hens subjected to PS at 17 and 20 weeks,
total production was not affected by
age at PS. Although heavy hens began
laying earlier, total production by
medium and light hens was greater
than that of heavy hens.
Average egg weights were great-
est in the medium, light, and PS at 20
weeks of age treatments. Similarly,
continued on page 6
TABLE 1. EXPERIMENTAL LIGHTING PROGRAMS
Photoperiod, h light:h dark
23h 16h 14h Increasing
.......... 23L:1ID 16L:8D 14L:10D 23L:1D
.......... 23L:1D 16L:8D 14L:1OD 6L:18D
.......... 23L:1D 16L:8D 14L:1OD 10L:14D
.......... 23L:1D 16L:8D 14L:10D 14L:10D
.......... 023L:1D 16L:8D 14L:1OD 18L:6D
.......... 23L:1D 16L:8D 14L:10D 23L:1D
.. 23L:1D 16L:8D 14L:1OD 23L:1D
CASS AND COMPONENT WEIGHTS OF 49-DAY-OLD BROILERS
SUBJECTED TO FOUR LIGHTING PROGRAMS
Light treatment
23h 16h 14h Increasing
cass, lb ... 4.37 4.38 4.30 4.29
s, Ib ....... 4.40 4.40 4.33 4.34
f fat, Ib ... .14 
.14 .15 
.15
,Ib ... b. 4.26 4.26 4.17 4.16
............ ..52 .52 .51 .50
............. . 62 .63 .63 .62
................ .76 .77 .76 .75
.... .20 .19 .18 .19
................ .86 .80 .79 .80
ss = chilled carcass -abdominal leaf fat.
livability. The lighting program of 16
hours light:8 hours dark used in the
AAES study was as efficacious as an
increasing light program for improving
bird livability and was easier to use.
J.A. Renden, S.F. Bilgili, and S.A. Kincaid
I I~-- I I ~~I I I lr--II I~-~- IIIIV I ~V II II~~ ~III I I IIV~le~-ll lil~ 11 1~~1111111\~ 11 ~
Variation in Response of Late- and Early-
Maturing Pullets to Phosphorus Deficiency
Do early- and late-maturing pullets
in a flock respond differently to varying
levels of dietary phosphorus? An Ala-
bama Agricultural Experiment Station
study was conducted to answer this
question.
The study examined the use of nor-
mal (0.7 percent, total) and low (0.4 per-
cent, total) dietary phosphorus levels.
In the study, the available phosphorus
levels in normal and low diets were
0.18 and 0.48 percent, respectively. Six
hundred Hyline W36 pullets, (18
weeks of age) were equally divided
between normal and low phosphorus
diets. Within each phosphorus group,
the early-mature (EM), normal-mature
(NM), and late-mature (LM) pullets
were identified based on comb size and
color and egg production records. Pul-
lets that began laying on or before 19
weeks of age were considered EM, and
the last 30 pullets to begin laying eggs
were considered LM. NM pullets were
excluded from the study.
As expected, pullets fed diets con-
taining normal phosphorus performed
better than the pullets on the low phos-
phorus diets. LM pullets on the low
phosphorus diets had lowerbone status
than the EM pullets. However, the LM
birds on the low diet also had lower
plasma phosphorus concentrations,
higher plasma ionic calcium concen-
trations, increased kidney tissue le-
sions, higher incidence of blocked ure-
ters and weak bones, and higher mor-
tality rates than the EM pullets. In addi-
tion, calcium depletion from the body
increased in EM and LM pullets as di-
etary phosphorus level was lowered.
EDITOR'S NOTE
Mention of company or trade names does not
indicate endorsement by the Alabama Agricul-
tural Experiment Station or Auburn University of
one brand over another. Any mention of nonlabel
uses or applications in excess of labeled rates of
pesticides or other chemicals does not constitute a
recommendation. Such use in research is simply
part of the scientific investigation necessary to fully
evaluate materials and treatments.
Information contained herein is available to all
persons without regard to race, color, sex, or national
origin.
September 1992 2M
Because phosphorus is essential
for bone growth, late-maturing pullets
may fail to develop adequate medul-
lary bone if pre-lay or early layer diets
contain inadequate phosphorus. Lack
ofadequate medullary bone growth,
which is a critical calcium reserve for
eggshell, will decrease performance of
these pullets and eventually lead to
osteopenia (weak bones) and death.
EM and LM pullets exist in every
flock, however, the proportion of these
pullets may vary from flock to flock.
Because EM and LM pullets respond
differently to marginal and low dietary
phosphorus, flock uniformity should
be considered when setting dietary
phosphorus specifications. If the flock
in question is less uniform, then a higher
margin of safety for dietary phosphorus
may be necessary.
S.K. Rao and D.A. Roland, Sr.
Early Egg Production, continued
more eggs weighing greater than 21
ounces per dozen were produced by
pullets subjected to rearing period feed
restriction and PS at 20 weeks. Weekly
egg weights increased similarly in all
treatments from an average of about 19
ounces per dozen at 25 weeks to 25
ounces per dozen at 39 weeks. Egg
weights were influenced principally
by age and there were only slight
differences among treatments at
the same age. So, differences in aver-
age egg weights and the production of
eggs of adequate size were due to the
greater percentage of total eggs laid by
hens of the heavy and 14-week PS treat-
ments early in the laying period.
Based on these results, it appears
that it may not be practical to stimulate
early egg production by breeder hens
since egg size is principally influenced
by age and does not respond to in-
creased body weights at the end of the
rearing period.
R.J. Lien and G.R. McDaniel
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