Factors Affecting the Transfer of Calcium (45Ca) from the
Hen's Diet to the Egg Shell
D. B. BRAGG,1 JANICE FLOYD AND E. L. STEPHENSON
Department of Animal Sciences, University of Arkansas, Fayetteville, Arkansas 72701
(Received for publication July 16, 1970)
dietary levels of vitamin D 3 . Turk and McGinnis (1964), showed that additional vitamin D 3 increased egg production, egg
weight, shell thickness and total calcium in
the egg shell.
Objectives of this study were to investigate the influence of calcium level and vitamin D 3 level in the laying diet on performance, shell quality and the movement of
dietary calcium to the egg shell. Radioactive calcium (45Ca) was used to determine
the apparent absorption, egg shell deposition as well as deposition and mobilization
of bone calcium.
E
1
Present address: Department of Poultry Science, The University of British Columbia, Vancouver 8, Canada.
MATERIALS AND METHODS
Forty-eight six-month old White Leghorn hens were used in feeding trials of 252
days (trial 1) and 28 days (trial 2). Birds
were maintained in individual wire cages
with feed and tap water supplied ad libitum. Four levels of dietary calcium (2.25,
2.75, 3.25, and 3.75 percent) and two levels of vitamin D 3 (660 and 2200 I.C.U./
kg.) were utilized. Changes in calcium level
were made by adjusting levels of calcium
carbonate and glucose monohydrate in the
basal diet (Table 1). Different levels of
vitamin D 3 were obtained by supplementing
vitamin D 3 to each diet.
Hens were dosed with 20 |xCi. of 45Ca
using 40 ml. of solution containing 0.5 (*Ci.
per ml. The dose was administered by pipette in 10 ml. quantities at 4-hour intervals beginning at 4:00 a.m. and ending 4:00
p.m. on the 14th day of each 28-day period. Eggs were collected for three consecutive days, beginning 24 hours following the
first 10 ml. dose, and feces were collected
167
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INTRODUCTION
XTENSIVE studies on the dietary calcium requirement for laying hens
have produced a great amount of information concerning the quantity of this mineral
necessary for optimum egg shell formation.
There is, however, considerable variation in
the findings of different investigators. Norris et al. (1934), Titus et al. (1937), Gutowska and Parkhurst (1942), and Berg et
al. (1944) have suggested dietary calcium
requirements which varied between 1.6 and
2.1 percent. Later investigators, Petersen et
al. (1960), Durham et al. (1960), Harms
and Waldroup (1961), Balloun and Marion (1962), and Reddy and Sanford
(1963) have shown that higher dietary calcium levels (2.75 to 4.60 percent) were
more effective in improving egg shell quality.
Driggers and Comar (1949) studied the
transfer of calcium from the diet to the egg
shell using 45Ca as a tracer. These investigators suggested that 60 to 75 percent of
the egg shell calcium was obtained directly
from the diet. Similar results were obtained
by O'Neil et al. (1949), and Shirley et al.
(1951).
Miller and Bearse (1934) reported that
vitamin D 3 fed at levels higher than the
recommended dietary requirement was ineffective in the improvement of production,
egg weight, and seasonal decline in shell
thickness. Anderson et al. (1957) were also
unable to improve shell quality with high
168
D. B. BRAGG, J. FLOYD AND E. L. STEPHENSON
RESULTS AND DISCUSSION
Trial 1. Egg production data (Table 2),
obtained with laying hens fed two levels
of dietary vitamin D 3 (660 and 2200
I.C.U.Ag-) and four levels of dietary calcium (2.25, 2.75, 3.25, and 3.75%), show
the importance of these two dietary components for maximum production.
Although not statistically significant, egg
production of hens fed the low level of vitamin D 3 increased with each gradient increase in dietary calcium from 2.25 to 3.75
TABLE 1.—Composition of basal diet1
Ingredient
Ground yellow corn
Ground oats
Wheat bran
Glucose monohydrate 2
Soybean meal (50% protein)
Alfalfa meal (17% protein)
Meat scraps
Fish solubles
Dried whey
Dicalcium phosphate
Salt (NaCl)
Trace minerals 3
Vitamin premix4
Total
Percent
49.65
10.00
10.00
6.67
9.00
2.00
2.00
1.00
1.50
2.65
0.50
0.03
5.00
100.00
1
Calcium carbonate was added at the expense of
glucosemonohydrate to vary the calcium content and
vitamin D 3 was supplemented to each diet.
2
Trade name Cerelose; manufactured by Corn
Products Co.
8
The composition of trace minerals in percent:
manganese 0.155, iron 0.240, magnesium 0.050, copper 0.032, calcium 0.011, iodine 0.007 and zinc
0.005.
4
Composition of Vitamin Premix is: ground yellow corn 4.73 kg. vitamin A (20,000 U.S.P. units/g.)
45.83 g., riboflavin 0.57 g., calcium pantothenate
1.14 g., niacin 2.77 g., folic acid 0.18 g., menadione
0.29 g., vitamin E 0.29 g., choline chloride 114.62 g.,
vitamin Bis 1.14 mg., ascorbic acid 5.68 g., arsanilic
acid (20%) 49.94 g., BHT 49.94 g., NF-180 (50 g./
lb.) 12.45 g.
percent. This indicated that the dietary
calcium requirement of hens receiving 660
I.C.U. vitamin D 3 per kilogram of diet was
at least 3.75 percent for egg production.
Hens receiving the high level of dietary
vitamin D 3 (2200 I.C.U./kg.) maintained
a higher rate of production with 2.25 percent calcium and maximum production was
observed with 3.25 percent dietary calcium.
These data suggested that the higher level
of dietary vitamin D 3 increased egg production, especially when the lower calcium
levels were fed.
Results of feed efficiency (kg. feed/doz.
eggs) data (Table 2) show a calcium X vitamin D 3 interaction (P < .01). Hens required more feed to produce a dozen eggs
as dietary calcium was elevated in the low
vitamin D 3 treatment. However, less feed
was required per dozen eggs produced as
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one day following administration. Eggs and
feces were collected one day before the second administration of 45Ca and before
each dose thereafter in order to correct for
residual 45Ca activity. Eggs produced and
feed additions were recorded daily. Average ambient temperature was determined
through the use of a continuous recording
thermometer.
Trial 1. Egg weight, shell strength
(measured in centimeters travel up an
inclined plane of a constant 800g. weight;
Romanoff, 1929), percent shell, calcium
content of shell, feces and 45Ca activity
of the shell and feces were determined.
Trial 2. Eggs were collected at S-day
intervals beginning 24 hours following 45Ca
administration for determination of calcium and 45Ca activity. One hen from each
dietary treatment was killed at 5-day intervals and the left tibia removed for calcium, phosphorus, and 45Ca activity determination. Phosphorus was determined by
the method described by Hawk et al.
(1945).
Calcium of egg shells and feces in trial 1
and bones in trial 2 were determined as
described by A.O.A.C. (1960). Radioactive
calcium activity in all samples was measured by a gas flow proportional counter.
Data were subjected to statistical analysis
by methods described by Steel and Torrie
(1960) and Snedecor (1956).
169
CALCIUM IN HEN'S DIETS
TABLE 2.—Influence of dietary calcium and vitamin D3 levels on production, feed efficiency,
egg weight, and shell quality with White Leghorn hens1
Ca Level
(%)
1
2
660
660
660
660
2200
2200
2200
2200
60.9
62.9
63.4
65.5
68.4
61.7
72.7
72.0
Kg. Feed 2
Doz. Eggs
Egg Wt.
(gms.)
Shell Str.
(cm.)
Shell Ca
(%)
Percent
Shell
1.88»b
1.89"b
1.96"b
2.02b
1.92"b
2.21 b
1.84"
1.82*
49. 4 cd
51.9°
52.3"
47.1a
48.1* b
48.6 b °
50.0 d
49.8 d
57.7* b
56.7" b
60.7" b
51.5" b
46.7"
51.2" b
61.7 b
61.3»
38.0 b
38. l b
38.3°
38. l b
38.9 b
37.8"
38.4° d
38. S d
8.77 b
9.02 d
9.14"
8.19"
9.04 d
8.93°
9.53"
9.27 f
Treatment means having different superscript letters are significantly different (P<.01).
CalciumXvitamin D 3 interaction (P<.01).
dietary calcium was increased in the high
vitamin D 3 diet.
Feed intake was similar for hens fed
diets containing either calcium level and
high vitamin D 3 . Therefore, the improvement in feed efficiency with high calcium
and vitamin D 3 was related to egg production. These results are in agreement with
the suggestion of Turk and McGinnis
(1964) who found that vitamin D 3 was involved in regulating ovulation and/or follicular growth in laying hens.
Egg weight data (Table 2) indicated
that at both levels of vitamin D 3 there was
a linear increase (P < .01) in egg weight
when dietary calcium was increased from
2.25 to 3.25 percent. Increasing the calcium
from 3.25 to 3.75 resulted in a significant
decrease in egg weight at the low level of
vitamin D 3 , whereas when the higher level
of this vitamin was fed the higher level of
calcium had no significant effect as compared to the 3.25 level.
Egg shell quality (Table 2) was measured by shell strength, calcium content of
shell and percent shell. Shell strength values increased with dietary calcium levels
up to 3.25 percent with both the high and
low levels of vitamin D 3 . However, these
values were statistically significant only between low calcium (2.25%) and high calcium (3.25 and 3.75%) within the high vitamin D 3 treatment.
The amount of calcium in the shell varied only slightly and, although significant
differences (P < .01) were obtained, no
trend due to treatment was established.
Percent shell was highest at the 3.25 percent dietary calcium level with either level
of vitamin D 3 .
The effect of ambient temperature (Table 3) indicated that a drop in mean temperature from 11.9 degrees to 4.3 degrees
C. resulted in decreased production. During
the next 28-day period the temperature
mean increased slightly, which was accompanied by a 9 percent increase in egg production. The temperature continued to increase until the experiment ended, but
there was no further increase in egg pro-
TABLE 3.—Effect of ambient temperature on egg
production, egg shell weight, shell strength,
percent shell and i6Ca activity in shell of eggs
laid by White Leghorn hens
Temperature
(C)>
Egg
Prod.
Shell
Wt.
(gm.)
Shell
Str.
(cm.)
%
Shell
«Ca
(%)
11.9
87.7
74.6
59.8
68.5
60.0
61.1
54.5
54.0
53.2
4.70
4.46
4.88
4.82
4.66
4.60
4.54
4.31
4.34
54.4
51.1
55.3
64.6
61.5
56.0
55.0
51.6
50.3
9.45
9.43
9.63
9.35
8.99
8.92
8.84
8.54
8.54
25.6
36.7
29.2
26.1
24.0
33.6
30.2
19.1
17.1
-.81
-.51
-.98
-.47
7.6
4.3
6.3
12.5
19.6
22.8
24.8
26.8
Corr. Coef.2
1
(%)
Ambient temperature means of each 28-day period beginning
in November and ending in July.
2
Correlation coefficient for shell quality criteria on ambient
temperature.
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2.25
2.75
3.25
3.75
2.25
2.75
3.25
3.75
Production
Vit. D 3
(I.C.U./kg.)
(%)
170
D. B. BRAGG, J. FLOYD AND E. L. STEPHENSON
TABLE 4.—Average percent i6Ca activity in egg shell
three consecutive days following ibCa
administration in White Leghorn hens
Percent of 46 Ca dose
Dietary treatment
Calcium
Vit. Ds
(%)
(I.C.U./kg.)
2.25
2.75
3.25
3.75
2.25
2.75
3.25
3.75
Average/day
660
660
660
660
2200
2200
2200
2200
—
First egg laid
Second egg laid
1
Days following
1
31.6+5.21
30.9 + 3.1
26.9 + 2.9
26.5 + 3.3
29.5 + 5.2
27.9+5.1
29.9+3.3
27.7±2.2
46
Ca administration
2
3
12.7±5.2
10.0 + 3.1
10.5+2.9
7.8+3.3
12.3+5.2
12.2+5.1
8.0+3.3
9.0±2.2
7.1 + 2.2
6.7 + 2.5
4.7+1.4
3.6+1.0
7.7 + 2.7
6.0 + 2 . 0
3.8+1.8
4.0+1.7
28.8 + 7.5
10.3 + 4.0
5.5 + 2 . 4
28.8+7.5
14.0 + 6.6
7.5±2.8
7.6 + 4 . 0
6.0+2.0
—
Standard Deviation.
absorption.
Examination of daily 45Ca secretion into
egg shells (Table 3) showed that 28.8, 10.3
and 5.5 percent of the 45Ca dose (administered at 4 hour intervals on a single day)
was secreted 1, 2 and 3 days following administration. Recovery of 45Ca activity
one day following dose was considerably
lower than reported by Driggers and Comar (1949). The lower values can probably be attributed to different methods of
administration of the isotope and different
collection procedures. Procedures employed
in this study were designed to represent
calcium utilization throughout a one-day
feeding period which is not comparable to a
single administration of the isotope.
Average 45Ca activity (Table 4) is not a
true representative value of the second and
third egg laid after isotope administration.
These values were higher, since some hens
laid the first egg on the second day and second egg on the third day. Therefore, the correct 45Ca activity secretion for the second
and third egg can only be obtained in egg
samples from hens that laid all three days
as shown at the bottom of Table 4.
Radioactive calcium activity secreted
when the first egg was laid on the second or
third day following administration showed
that laying hens increased the body calcium reserve between each clutch. The
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duction; in fact, egg production gradually
declined.
Eggs that had the greatest shell weight
and highest percent of shell were not necessarily the eggs which possess the greatest
shell strength. It will also be noted that
eggs which contained the greatest amount
of 45Ca activity were neither those that
had the highest shell weight, nor the greatest percentage of shell. The amount of
45
Ca in the egg shell likewise was not an indication of shell strength.
Negative coefficients of correlation were
observed for shell weight ( — .81), shell
strength ( — .51), percent shell ( — .98)
and 45Ca activity ( — .47) in shells when
compared to ambient temperature means.
These data (Table 3) with their corresponding correlation coefficients show that
high ambient temperature resulted in a
negative effect on egg shell quality and
45
Ca activity transported from the digestive system to the egg shell. These effects
were considered as an expression of poor
mobilization and metabolism of dietary
calcium for egg shell formation by laying
hens during periods of high environmental
temperature. It should also be noted that
high temperature occurred during the latter part of the laying period. Therefore,
ambient temperature was compounded
with duration of lay and the decreasing
egg shell quality was probably related to
both factors.
Secretion of 45Ca activity (Table 4)
into egg shells 24 hours following oral administration decreased with each increment
of calcium fed. The magnitude of reduction
in 45Ca activity due to increasing dietary
calcium was 31.8 to 26.S and 29.5 to 27.7
percent of 45Ca dose when fed with low
and high vitamin D 3 respectively. The radioactive calcium was diluted with nonradioactive calcium in the digestive system.
Therefore, each increase in dietary calcium
results in competition at the cite of 45Ca
171
CALCIUM IN HEN'S DIETSTABLE S.—Average percent of' i5Ca activity, total calcium in feces excreted and estimated calcium
apparent absorption during the 24-hour period following administration with White Leghorn hens
Percent of 45Ca dose1'2
Vit. D 3
Calcium
(I.C.U./kg.)
level
24.3+4.7"
28.6 + 8.3" b
31.9 + 7.8 b
30.5 + 8.3 b
28.2 + 5.l» b
2S.6 + 8.2" b
28.8 + 7.0»b
28.5 + 5.3* b
Lay
23.9 +
27.9 +
29.1 +
27.5 +
25.9 +
26.8 +
26.5 +
27.1 +
6.6
10.5
11.0
10.0
5.0
9.0
8.2
6.7
Non-Lay
24.5 + 7.8
29.6 + 6.3
33.3 + 6.9
33.4+10.3
26.6 + 8.8
31.9 + 10.0
32.8 + 7.3
36.0 + 17.4
4.6
7.2
7.1
9.3
4.6
6.6
7.6
9.3
Absorptior ' (%) 4
45
Ca
75.7
71.4
68.1
69.5
71.8
71.4
71.2
71.5
Ca
74.2
67.3
72.6
69.1
74.2
69.8
70.8
69.1
1
Means with unlike superscripts are significantly different (P<.01).
Treatments means with standard deviation.
Fecal calcium calculated on dry weight basis.
4
Estimated apparent absorption, 45Ca and non-radioactive Ca.
2
3
body 45Ca reserve was mobilized by these
hens in greater amounts for the first egg
laid on the second day than by hens that
laid both the first and second day.
Dietary vitamin D 3 had no effect on calcium content of excreta (Table 5). However, when dietary calcium increased from
2.25 to 3.75 percent, there was a significant
increase in fecal 45Ca activity (P < .01)
with a corresponding increase in total fecal
calcium of 4.6 to 9.3 percent.
Data concerning 45Ca activity excreted
in the feces one day following administration were separated into three classifications: average for all hens (total); average
level of vitamin D 3 (2200 I.C.U./kg.) apparently improved the absorption of dietary 45Ca during the period of egg shell
formation when dietary levels of calcium
increased from 2.75 to 3.75. Results also
suggested that hens utilized calcium more
efficiently during the period of egg shell
formation since hens that did not lay excreted greater 45Ca activity.
Through the use of fecal excretion data
an estimated apparent absorption was calculated for radioactive calcium and non-radioactive calcium fed to laying hens (Table
5). Apparent absorption (%) was calculated as follows:
45
46
Ca activity of dose — fecal 45Ca activity X 100
45
Ca activity of dose
(GMS feed consumed) (Ca content) — GMS feces) (Ca content) X 100
App. Abs. =
(GMS feed consumed) (Ca content)
Ca App. Abs. =
for hens that laid (lay); and average for
hens that did not lay (non-lay) one day
following 45Ca administration. Hens that
laid (lay) excreted smaller amounts of radioactive calcium with each increment of
dietary calcium at both vitamin D 3 levels.
Non-lay hens excreted greater 45Ca activity with each increment of dietary calcium
in both vitamin D 3 treatments. The high
The two methods of estimating absorption
agreed relatively well. However, there was
some evidence that indicated a difference in
total absorption between radioactive and
non-radioactive calcium in the presence of
a high level of dietary vitamin D 3 .
These data indicate that laying hens absorbed approximately 70 percent of the dietary calcium consumed. Absorption was
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660
660
660
660
2200
2200
2200
2200
2.25
2.75
3.25
3.75
2.25
2.75
3.25
3.75
Total
Fecal3
Ca (%)
172
D. B. BRAGG, J. FLOYD AND E. L. STEPHENSON
SUMMARY
The effect of temperature, dietary calcium level, and vitamin D 3 on egg producTABLE 6.—Average percent o/4BCo activity in bone at
5-day intervals following last i&Ca administration as ajfected by dietary vitamin D%
and calcium with White Leghorn hens
Percent of 45 Ca dose
Treatment
D a y s following 45 Ca administration
1
6
11
16
21
26
660 (I.C.U.AS-) Vit. D»i
2200 (I.C.U./kg.) Vit. Ds 1
1.4
2.1
1.5
1.5
1.4
1.4
1.4
1.1
1.1
1.1
1.0
1.2
2.25%
2.75%
3.25%
3.75%
1.6
1.7
1.5
2.2
1.5
1.3
1.9
1.7
1.4
1.4
1.3
1.5
0.7
1.7
1.0
1.2
1.2
1.1
1.0
1.2
1.0
1.1
1.0
1.2
1
2
Ca*
Ca 2
Ca 2
Ca 2
Represents the means for 4 individual observations.
Represents the means for 2 individual observations.
TABLE 7.—Average percent 46Ca activity at 5-day
intervals in egg shells folloiving ihCa administration as ajfected by dietary vitamin Ds and
calcium with White Leghorn hens
Percent of
Treatment
2.25%
2.75%
3.25%
3.75%
Ca 22
Ca
Ca 22
Ca
Interval means
1
2
Ca dose
11
16
21
26
16.8 2.5
17.5 2 . 4
1.6
1.5
0.9
1.1
0.7
0.7
0.6
0.6
19.1 3.5
17.4 2 . 4
16.9 2.2
15.3 1.9
1.7
1.5
2.2
0.8
1.3
1.1
1.0
0.7
0.9
0.5
0.6
0.7
0.8
0.5
0.5
0.6
17.2 2.5
1.6
1.0
0.7
0.6
1
660 I.C.U./kg. Vit. Dji
2200 I.C.U./kg. Vit. Ds 1
45
Days following *5Ca administration
6
Represents the means of 4 individual observations.
Represents the means of 2 individual observations.
tion, shell quality, and amount of calcium
transported from feed to the egg shell, or
bone ( 45 Ca), was studied using White
Leghorn hens.
Egg production appeared to be adversely
affected by either high or low temperatures; whereas, high temperatures appeared
to decrease both shell quality and the
amount of 45Ca activity secreted into the
egg shell.
The levels of dietary calcium required
for optimum egg production varied with
the amount of vitamin D 3 fed. At the low
level of vitamin D 3 (660 I.C.U./kg.) maximum egg production was obtained at the
3.75 percent calcium level, whereas with
the higher vitamin D 3 level (2200 I.C.U./
kg.) 3.25 percent of calcium was adequate.
At the lower level of dietary calcium
(2.25 percent) the hen appeared to use a
greater percentage of dietary 45Ca. This
was indicated both by total absorption and
the amount of activity which appeared in
egg shells. Estimated apparent absorption
by non-radioactive and radioactive calcium
indicated that hens retain approximately
70% of the dietary calcium. However, less
than one-half of this amount was available
for egg shell formation as indicated by
transfer of dietary 45Ca to the egg shell.
Most of the 45Ca activity which was retained in either bone or egg shell was mobi-
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slightly more efficient with diets containing
2.25 percent calcium than with higher levels. High levels of vitamin D 3 improved
and stabilized absorption when calculated
by isotopes, but little difference was noted
with non-radioactive calculations.
45
Ca activity in the bone (Table 6) was
highest one day following administration
with hens fed high vitamin D 3 . In most
cases, the greatest amount of isotope was
found in bones of hens fed the higher calcium levels.
The greatest amount of egg shell 45Ca
activity (Table 7) was noted during the
first 5 days. A progressive decrease occurred each 5 days thereafter. Hens fed low
dietary calcium secreted more 45Ca activity into the egg shell on the first and sixth
day following administration than did hens
fed the higher calcium levels. This suggested that hens fed lower dietary calcium
mobilized a greater amount of body calcium for egg shell formation than hens fed
higher calcium levels. Since egg shells produced with the higher calcium levels exhibited both more total weight and total calcium, the low 45Ca activity values were
undoubtedly due to dilution with non-radioactive calcium.
CALCIUM IN HEN'S DIETS
lized within the first five days, and the
amount which was retained in bone continued to decrease during the 26 days in
which elimination was measured.
REFERENCES
Ed., The Blakiston Company, Inc., New York.
Miller, M. W., and G. E. Bearse, 1934. Phosphorus
requirements of laying hens. Washington Agr.
Exp. Sta. Bull. 306-5-20.
Norris, L. C , G. F. Heuser, A. T. Ringrose and
H. S. Wilgus, 1934. Studies on calcium requirements of laying hens. Poultry Sci. 13: 308-309.
O'Neil, J. B., M. R. Bertie and J. W. T. Spinks,
1949. Determination of calcium utilization in
the laying hen by means of radio-calcium. Poultry Sci. 28: 778-779.
Petersen, C. F., D. H. Concord, D. H. Lumijaryi,
E. A. Sauter and C. E. Lampman, 1960. Studies on the calcium requirement of high producing White Leghorn hens. Idaho Agr. Exp. Sta.
Res. Bull. 44.
Reddy, C. V., and P. E. Sanford, 1963. Influence
of dietary calcium in laying rations on shell
quality and interior quality of eggs. Poultry Sci.
42: 1302.
Romanoff, A. L., 1929. Study of the physical
properties of hen's egg shell in relation to the
function of shell secretory glands. Biol. Bull.
56:352.
Shirley, R. L., J. C. Driggers, J. McCall, G. K.
Davies and N. R. Mehrof, 1951. Excretion and
retention of P 3 2 and Ca 45 by laying hens. Poultry Sci. 30: 730-734.
Snedecor, G. W., 1956. Statistical Methods, 5th
Ed. Iowa State College Press. Ames.
Steel, R. G. D., and J. H. Torrie, 1960. Principles
and Procedures of Statistics, McGraw-Hill,
New York.
Titus, H. W., T. C. Byerly, N. R. Ellis and R. B.
Nestler, 1937. Effect of calcium and phosphorus
content of diet of chickens on egg production
and hatchability. Poultry Sci. 16: 118-128.
Turk, J. L., and J. McGinnis, 1964. Influence of
vitamin D on various aspects of the reproductive process in mature hens. Poultry Sci. 4 3 :
539-546.
NEWS AND NOTES
Continued from page 134)
did salmonella typing for the British Columbia
Public Health Laboratory. In 1965 he completed a
B.Sc. degree, majoring in microbiology, at the
University of British Columbia. He then worked
for the British Columbia Department of Agriculture and became Head Bacteriologist at the Veterinary Laboratory, Abbotsford. He commenced
graduate studies at the University of Saskatchewan
in 1968.
He is concerned primarily with the discovery of
more efficient methods of detecting and eradicating
Salmonella and Arizona in the avian species. He is
interested especially in carrier birds and in detecting
the organisms in eggs.
(Continued on page 203)
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