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The Relationship Between Blood Calcium and Blood Phosphorus and the Effect of Variations in the Calcium Content of the Ration on Ovulation and Blood Calcium Changes in the Laying Pullet
H. J. DEOBALD, J. B. CHRISTIANSEN, AND E. B. HART
Department of Agricultural Chemistry AND
J. G. HALPIN
Department of Poultry Husbandry, University of Wisconsin, Madison (Presented at Annual Meeting, August 1937; received for publication August 16, 1937)
T N a previous paper by Deobald, Lease, well known (MacOwan, 1932; Buckner, -*- Hart, and Halpin (1936) it was shown Martin, and Hull, 1930; Greenberg et al, that the blood calcium of the laying pul- 1936). let does not show any marked variation The following experiments were planned during an entire laying cycle and that ap- to show the nature of the changes in the proximately 10 percent of the calcium in blood calcium of (1) pullets coming into the bones of a laying pullet is available for lay, (2) pullets laying on different levels egg shell formation when the calcium is of available calcium in the diet and (3) removed from the ration. the relation of the total phosphorus in the Feinberg, Hughes, and Scott (1937) and blood to the variations in the blood calCommon (1936) have published data in cium curve. substantial agreement with these findings. EXPERIMENTAL Common (1936) has shown quite wide The basal ration used, the method for obvariations in calcium content of the blood taining blood samples, and the methods for of individual hens over a four-month calcium analysis of the blood have been period when samples for analysis were reported (Deobald et al, 1936). The total taken at approximately monthly intervals. blood phosphorus was determined by the Riddle (1926) working with pigeons, Fiske and Subbarow (192S) method using and Roepke and Hughes (1935) working hydrogen peroxide to hasten the sulphuric with laying pullets, have reported a marked acid digestion of the blood sample. Blood rise in total serum phosphorus when the samples were taken bi-weekly. It was found birds approach sexual maturity. The rise b y d a i l y s a m p l i n g t h a t t h e c h a n g e s o c . in blood calcium during this period is also ~ c u r r f n g i n ^ b l o o d c a l d u m c o u W b e Published with the permission of the Director|f I accurately followed by sampling every 3 of the Wisconsin Agricultural Experiment Station "to 4 days.
11
[1141
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
T h e Relationship Between Blood Calcium and Blood Phosphorus and the Effect of Variations in the Calcium Content of the Ration on Ovulation and Blood Calcium Changes in the Laying Pullet/
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
Blood Calcium Changes as a Pullet Approaches the Laying Period Twelve Barred Rock pullets, about to lay, were placed on the low calcium basal ration and fed 1 gm. of ground oyster shells daily by capsule. A typical curve for
ration with free access to oyster shells showed essentially the same curves for this period. However, on 1 gm. of oyster shells daily, egg production was almost completely inhibited by the low level of calcium allowed and egg eating was prevalent.
Mg. Ca/100 Oa.
1 On
I\ / \ / /
Ik 12 I 10
\ \
20
/
Cad 3 chf nge ' o l o t Ca
it 1
\ \
'
\
^ \
/J /
f
1\
\ \ \
\
/ /
v \
V
/ \ ^, / /
\
>
/ \- ^ /
v
1
I\
1\ \
Y
>/
Hen Laylr % on Low ( a Int ake
/ I / \ / I \ /
IS 16 Ik
/
10
/ / /
\
8
f
\\ \
/ \
/
12
A
t
/
r
0
f
1
\
*rs o
Egfg ' 0
Pui: e t a ) atura ng o» 1 Ol . CaC Oj D< l l y ]L
>
1
k
Weeks
I
i>
1
i5
< .
CHART I. Blood calcium changes of pullets maturing and laying on 1 gm. of oyster shells daily and the effect of removing the 1 gm. of oyster shell supplement.
the variation in blood calcium under these conditions is shown in Chart I. The blood calcium is quite constant at the normal basic level for immature birds, which is 7-9 mg. per 100 gms. of whole blood. A marked rise occurs about 15-25 days before the first egg is laid. The blood calcium rises to 16-24 mg. per 100 gms. whole blood in about 7 days and then falls at about the same rate. Egg production always begins at least 3-7 days after the peak of the blood calcium curve is reached. Later trials with pullets on the same basal
Effect of Variation of the Calcium Content of the Ration on the Calcium Content of the Blood Nine of the above pullets were transferred to a laying battery and kept under constant electric illumination to eliminate any effect of clutch laying. They were divided into the following groups. Group I—Basal ration Group II—Basal ration + 1 gm. of oyster shells daily Group III—Basal ration + oyster shells ad libitum
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
v1
18 16
115
116
H. J. DEOBALD AND OTHERS
level of blood calcium followed by a rise and fall very similar to that for a pullet about to come into lay (Chart II, top). Egg production, again, did not begin until at least 3 days after the peak in the blood calcium had been reached. When the calcium was removed from the ration of heavily laying pullets receiving the stock ration, the changes in blood calcium recorded in Chart II (lower) resulted. Here, laying continued for about 10 days with the blood calcium content decreasing to the basic level by the end of this period. Egg production then ceased and a typical low calcium curve followed. The egg shells became progressively thinner after the calcium was withdrawn from the ration. The data for egg shell weight change under similar conditions are given in a previous paper by Deobald et al (1936). In general, however, there is no correlation between egg shell weight and the level of
JJg. 0a/100 O n . Who"!ftBlOQfl
isff R«tnrtVn"
4
Teeks
5
CHART II. The effect of removal and replacement of ad libitum calcium supplement to the ration.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
Three other pullets (Group IV) which were on the regular stock ration with free access to oyster shells, were also placed in the batteries and fed the basal ration without any calcium addition. The curves for the blood calcium in groups I and II were similar in every respect. As long as the calcium content of the ration remained suboptimal and inhibited egg production, the blood calcium continued to show regular, almost cyclic, variations which were quite characteristic for each individual hen. Chart I (top curve) illustrates these changes. Egg production under low calcium feeding occurred at periods when the blood calcium was low or descending. The pullets in group III, which were allowed free access to oyster shells after receiving but 1 gm. of oyster shells daily, showed the characteristic changes. There was a delay of 3-20 days at a very low
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
117
Kg. C »/10( Gn. Wiol B Bl< od
Heav . l y L lying Hen !a ad l i b .
20 IS 2
1
16
1
2
3
l»
7
•J
k
2
•?•
?
It
f
7
k
1 E res
\n
o\ 0
l*f
Poor '.s La ring ten la ad l i b .
>\ n
o\
IP
L
y
\
J-
i
\
/
Ik
0
\
Si . Oa( O3 el ange t o l o r Ca
16
v
/ \ k
/
12 10
/o
/
\
\ ,**
°\
N
J
•Hen • l a y l n ; on Low ia In take
/
\
/
\
EgB " 0
' 1
2
4
I
r
i
y
CHART III. Comparison of blood calcium variations of poorly and heavily laying pullets with pullets laying on low calcium intake.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
The Effect of High and Low Egg Production on the Variations in Blood Calcium In the experiments where ad libitum calcium was fed, it was observed that under heavy laying conditions there was little or no variation in blood calcium over periods as long as 8 to 12 weeks. However, when this production fell off, the blood calcium also showed variability coincident with the break in the series of regular ovulations. Chart III shows the blood calcium for a heavily laying pullet (67 eggs in 74 days) as compared with a poor layer on optimum calcium and, for the purpose of comparison, the typical low production curve for pullets on suboptimal calcium intake. These curves indicate that any factor which influences the rate of ovulation will also cause fluctuations in blood calcium. In general, it has been noted that the greater
blood calcium. Normal egg shells are produced during periods of low as well as high blood calcium. It seemed advisable at this time to determine whether the delay period before the rise in blood calcium of pullets which were changed from low to optimum calcium rations could be shortened by immediate ingestion of a large amount of available calcium. Accordingly, 3 pullets which had been receiving 1 gm. of oyster shells daily, were force-fed 5 gms. of ground oyster shells by capsule and then allowed oyster shells ad libitum. The resulting delay before the rise in blood calcium was entirely similar to the delay period of pullets given free access to calcium without forced feeding. Thus the presence of the calcium in the tract is evidently not a factor in producing this delay in the rise in blood calcium and egg production.
118
H. J. DEOBALD AND OTHERS
cordingly, 3 pullets on a high calcium ration, which were about to lay, were bled bi-weekly and both calcium and total phosphorus in the whole blood were determined on each sample. Chart IV shows the relation between the variation in blood calcium and whole blood phosphorus during this period. The variation in blood calcium is almost exactly correlated with the blood phosphorus changes except for the initial rise in blood calcium which occurs just before the first egg is laid. A change of approximately 5 mg. per 100 gm. in the phosphorus content of the blood is associated with a 1 mg. per 100 gm. change in blood calcium.
Relation between the Blood Calcium Variation and the Total Phosphorus Content oj the Blood It has been shown that lipoid phosphorus and protein phosphorus in the serum rise at maturity in the fowl coincident with the rise in blood calcium and also that calcium and phosphorus low rations give similar curves for blood calcium. Therefore it seems probable that the phosphorus in the blood of the laying hen might bear some relationship to the calcium content. Ac-
Ca/l 00 0l ole I lood
.
— W! ole _. — mole
DISCUSSION
It is evident from these data that the great variations in the calcium content of hen's blood reported in the literature can be attributed to the many varying factors surrounding the pullet at the time the investigation is made. The blood calcium content may be high or low in a spasmodi-
I lood Ca I lood P
Mg. Tota: Wholi
P/1C D flras Bloc 3.
iim l-m
A
7/
/
A
1
1/ 1 1
v.
i 1
/
;
N
S.
\pn
\
\\
—-/
\l
\ /
/
/
nn inn 90
\; 5 1
2
1*
3
*o
i
*
s
1
5
6
H
3 7
8
6
3 9
10
0
11
Eggs
12 Weeks
CHART IV. Concurrent variations in blood calcium and whole blood phosphorus in laying pullets.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
the fluctuation in blood calcium, the poorer the egg production of the pullet, regardless of the reason for this poor production. For instance, when Fe 2 (S0 4 ) 8 was fed at a level calculated to combine with half the total phosphorus in the ration as FeP0 4 (Deobald and Elvehjem, 1935) and calcium was allowed ad libitum, egg production virtually ceased and a typical low calcium curve and poor egg production resulted.
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
SUMMARY
1. The nature of the rise in blood calcium which occurs as pullets approach maturity is graphically shown by means of bi-weekly analyses of the blood of individual pullets. 2. High blood calcium is not an indication of egg production. Eggs are usually laid during periods of low, constant or descending blood calcium. 3. Changes in blood calcium are associated primarily with spasdomic egg production in the laying pullet. Heavy production is correlated with periods of
little or no variation in the blood calcium. 4. Total phosphorus content of the blood is in direct correlation with the calcium content, except during the initial rise in blood calcium just preceding the laying period. REFERENCES
Buckner, G. D., J. H. Martin, and F. E. Hull, 1930. The distribution of blood calcium in the circulation of laying hens. Am. J. Physiol. 93: 86-89. Buckner, G. D., J. H. Martin, and W. M. Insko, Jr., 1930. The blood calcium of laying hens varied by the calcium intake. Am. J. Physiol. 94:692-695. Common, R. H., 1936. Serum phosphatase in the domestic fowl. J. Agr. Sci. 26:492-508. Deobald, H. J., E. J. Lease, E. B. Hart, and J. G. Halpin, 1936. Studies on the calcium metabolism of laying hens. Poul. Sci. 15:179185. Deobald, H. J., and C. A. Elvehjem, 1935. The effect of feeding high amounts of soluble iron and aluminum salts. Am. J. Physiol. 111:118123. Feinberg, J. H., J. S. Hughes, and H. M. Scott, 1937. Fluctuations of calcium and inorganic phosphorus in the blood of the laying hen during the cycle of one egg. Poul. Sci. 16:132-134. Fiske, C. H., and Y. Subbarow, 1925. The colorimetric determination of phosphorus. J. Biol. Chem. 66:375-400. Greenberg, D. M., C. E. Larson, Paul B. Pearson, and B. R. Burmeister, 1936. The state and partition of the calcium and inorganic phosphorus in the serum of the fowl. Effect of growth and ovulation. Poul. Sci. 15:483-489. MacOwan, Marion, 1932. Observations on the ductless glands, the serum calcium and egg laying in the fowl. Quart. J. Exp. Physiol. 21:383392. Riddle, O., and L. B. Dotti, 1936. Blood calcium in relation to anterior pituitary and sex hormones. Science 84:557-559. Riddle, O., and W. H. Reinhart, 1926. Blood calcium changes in the reproductive cycle. Am. J. Physiol. 76:660-676. Roepke, R. R., and J. S. Hughes, 1935. Phosphorus partition in the blood serum of laying hens. J. Biol. Chem. 108:79-83. Russell, W. C , C. H. Howard, and H. F. Hess, 1930. The relationship in the hen between the development of the ova, blood calcium and the antirachitic factor. Science 72:505-506.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
cally laying hen, depending entirely upon the time at which the sample is taken. Likewise, in a non-laying pullet, high as well as low blood calcium may result depending on the phase of the cycle at the time the blood is drawn. The observation often made (Greenberg, 1936; MacOwan, 1932) that higher blood calcium is recorded just before egg production, is in general verified by these findings. It is altogether possible, however, to get just as high values for blood calcium in a normally laying pullet producing about 3 eggs per week provided the samples are taken at the various peaks in the blood calcium curve. It is evident that the ovary must function in some way as a regulatory mechanism. The blood calcium is at a fairly uniform level only when the ovary is uniformly active as in a heavily laying bird, or passive as in the immature bird. Riddle (1936) demonstrated a marked rise of blood calcium in pigeons when oestrin was injected. Since the parathyroids (MacOwan, 1932) and the ovaries (Russell, Howard, and Hess, 1930) have already been associated with egg production, and the blood calcium variations are also associated with this change, there is a strong indication that the ovarian hormone, oestrin, is one of the factors responsible for the observed blood calcium and blood phosphorus variations in the laying pullet.
119
Department of Agricultural Chemistry AND
J. G. HALPIN
Department of Poultry Husbandry, University of Wisconsin, Madison (Presented at Annual Meeting, August 1937; received for publication August 16, 1937)
T N a previous paper by Deobald, Lease, well known (MacOwan, 1932; Buckner, -*- Hart, and Halpin (1936) it was shown Martin, and Hull, 1930; Greenberg et al, that the blood calcium of the laying pul- 1936). let does not show any marked variation The following experiments were planned during an entire laying cycle and that ap- to show the nature of the changes in the proximately 10 percent of the calcium in blood calcium of (1) pullets coming into the bones of a laying pullet is available for lay, (2) pullets laying on different levels egg shell formation when the calcium is of available calcium in the diet and (3) removed from the ration. the relation of the total phosphorus in the Feinberg, Hughes, and Scott (1937) and blood to the variations in the blood calCommon (1936) have published data in cium curve. substantial agreement with these findings. EXPERIMENTAL Common (1936) has shown quite wide The basal ration used, the method for obvariations in calcium content of the blood taining blood samples, and the methods for of individual hens over a four-month calcium analysis of the blood have been period when samples for analysis were reported (Deobald et al, 1936). The total taken at approximately monthly intervals. blood phosphorus was determined by the Riddle (1926) working with pigeons, Fiske and Subbarow (192S) method using and Roepke and Hughes (1935) working hydrogen peroxide to hasten the sulphuric with laying pullets, have reported a marked acid digestion of the blood sample. Blood rise in total serum phosphorus when the samples were taken bi-weekly. It was found birds approach sexual maturity. The rise b y d a i l y s a m p l i n g t h a t t h e c h a n g e s o c . in blood calcium during this period is also ~ c u r r f n g i n ^ b l o o d c a l d u m c o u W b e Published with the permission of the Director|f I accurately followed by sampling every 3 of the Wisconsin Agricultural Experiment Station "to 4 days.
11
[1141
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
T h e Relationship Between Blood Calcium and Blood Phosphorus and the Effect of Variations in the Calcium Content of the Ration on Ovulation and Blood Calcium Changes in the Laying Pullet/
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
Blood Calcium Changes as a Pullet Approaches the Laying Period Twelve Barred Rock pullets, about to lay, were placed on the low calcium basal ration and fed 1 gm. of ground oyster shells daily by capsule. A typical curve for
ration with free access to oyster shells showed essentially the same curves for this period. However, on 1 gm. of oyster shells daily, egg production was almost completely inhibited by the low level of calcium allowed and egg eating was prevalent.
Mg. Ca/100 Oa.
1 On
I\ / \ / /
Ik 12 I 10
\ \
20
/
Cad 3 chf nge ' o l o t Ca
it 1
\ \
'
\
^ \
/J /
f
1\
\ \ \
\
/ /
v \
V
/ \ ^, / /
\
>
/ \- ^ /
v
1
I\
1\ \
Y
>/
Hen Laylr % on Low ( a Int ake
/ I / \ / I \ /
IS 16 Ik
/
10
/ / /
\
8
f
\\ \
/ \
/
12
A
t
/
r
0
f
1
\
*rs o
Egfg ' 0
Pui: e t a ) atura ng o» 1 Ol . CaC Oj D< l l y ]L
>
1
k
Weeks
I
i>
1
i5
< .
CHART I. Blood calcium changes of pullets maturing and laying on 1 gm. of oyster shells daily and the effect of removing the 1 gm. of oyster shell supplement.
the variation in blood calcium under these conditions is shown in Chart I. The blood calcium is quite constant at the normal basic level for immature birds, which is 7-9 mg. per 100 gms. of whole blood. A marked rise occurs about 15-25 days before the first egg is laid. The blood calcium rises to 16-24 mg. per 100 gms. whole blood in about 7 days and then falls at about the same rate. Egg production always begins at least 3-7 days after the peak of the blood calcium curve is reached. Later trials with pullets on the same basal
Effect of Variation of the Calcium Content of the Ration on the Calcium Content of the Blood Nine of the above pullets were transferred to a laying battery and kept under constant electric illumination to eliminate any effect of clutch laying. They were divided into the following groups. Group I—Basal ration Group II—Basal ration + 1 gm. of oyster shells daily Group III—Basal ration + oyster shells ad libitum
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
v1
18 16
115
116
H. J. DEOBALD AND OTHERS
level of blood calcium followed by a rise and fall very similar to that for a pullet about to come into lay (Chart II, top). Egg production, again, did not begin until at least 3 days after the peak in the blood calcium had been reached. When the calcium was removed from the ration of heavily laying pullets receiving the stock ration, the changes in blood calcium recorded in Chart II (lower) resulted. Here, laying continued for about 10 days with the blood calcium content decreasing to the basic level by the end of this period. Egg production then ceased and a typical low calcium curve followed. The egg shells became progressively thinner after the calcium was withdrawn from the ration. The data for egg shell weight change under similar conditions are given in a previous paper by Deobald et al (1936). In general, however, there is no correlation between egg shell weight and the level of
JJg. 0a/100 O n . Who"!ftBlOQfl
isff R«tnrtVn"
4
Teeks
5
CHART II. The effect of removal and replacement of ad libitum calcium supplement to the ration.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
Three other pullets (Group IV) which were on the regular stock ration with free access to oyster shells, were also placed in the batteries and fed the basal ration without any calcium addition. The curves for the blood calcium in groups I and II were similar in every respect. As long as the calcium content of the ration remained suboptimal and inhibited egg production, the blood calcium continued to show regular, almost cyclic, variations which were quite characteristic for each individual hen. Chart I (top curve) illustrates these changes. Egg production under low calcium feeding occurred at periods when the blood calcium was low or descending. The pullets in group III, which were allowed free access to oyster shells after receiving but 1 gm. of oyster shells daily, showed the characteristic changes. There was a delay of 3-20 days at a very low
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
117
Kg. C »/10( Gn. Wiol B Bl< od
Heav . l y L lying Hen !a ad l i b .
20 IS 2
1
16
1
2
3
l»
7
•J
k
2
•?•
?
It
f
7
k
1 E res
\n
o\ 0
l*f
Poor '.s La ring ten la ad l i b .
>\ n
o\
IP
L
y
\
J-
i
\
/
Ik
0
\
Si . Oa( O3 el ange t o l o r Ca
16
v
/ \ k
/
12 10
/o
/
\
\ ,**
°\
N
J
•Hen • l a y l n ; on Low ia In take
/
\
/
\
EgB " 0
' 1
2
4
I
r
i
y
CHART III. Comparison of blood calcium variations of poorly and heavily laying pullets with pullets laying on low calcium intake.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
The Effect of High and Low Egg Production on the Variations in Blood Calcium In the experiments where ad libitum calcium was fed, it was observed that under heavy laying conditions there was little or no variation in blood calcium over periods as long as 8 to 12 weeks. However, when this production fell off, the blood calcium also showed variability coincident with the break in the series of regular ovulations. Chart III shows the blood calcium for a heavily laying pullet (67 eggs in 74 days) as compared with a poor layer on optimum calcium and, for the purpose of comparison, the typical low production curve for pullets on suboptimal calcium intake. These curves indicate that any factor which influences the rate of ovulation will also cause fluctuations in blood calcium. In general, it has been noted that the greater
blood calcium. Normal egg shells are produced during periods of low as well as high blood calcium. It seemed advisable at this time to determine whether the delay period before the rise in blood calcium of pullets which were changed from low to optimum calcium rations could be shortened by immediate ingestion of a large amount of available calcium. Accordingly, 3 pullets which had been receiving 1 gm. of oyster shells daily, were force-fed 5 gms. of ground oyster shells by capsule and then allowed oyster shells ad libitum. The resulting delay before the rise in blood calcium was entirely similar to the delay period of pullets given free access to calcium without forced feeding. Thus the presence of the calcium in the tract is evidently not a factor in producing this delay in the rise in blood calcium and egg production.
118
H. J. DEOBALD AND OTHERS
cordingly, 3 pullets on a high calcium ration, which were about to lay, were bled bi-weekly and both calcium and total phosphorus in the whole blood were determined on each sample. Chart IV shows the relation between the variation in blood calcium and whole blood phosphorus during this period. The variation in blood calcium is almost exactly correlated with the blood phosphorus changes except for the initial rise in blood calcium which occurs just before the first egg is laid. A change of approximately 5 mg. per 100 gm. in the phosphorus content of the blood is associated with a 1 mg. per 100 gm. change in blood calcium.
Relation between the Blood Calcium Variation and the Total Phosphorus Content oj the Blood It has been shown that lipoid phosphorus and protein phosphorus in the serum rise at maturity in the fowl coincident with the rise in blood calcium and also that calcium and phosphorus low rations give similar curves for blood calcium. Therefore it seems probable that the phosphorus in the blood of the laying hen might bear some relationship to the calcium content. Ac-
Ca/l 00 0l ole I lood
.
— W! ole _. — mole
DISCUSSION
It is evident from these data that the great variations in the calcium content of hen's blood reported in the literature can be attributed to the many varying factors surrounding the pullet at the time the investigation is made. The blood calcium content may be high or low in a spasmodi-
I lood Ca I lood P
Mg. Tota: Wholi
P/1C D flras Bloc 3.
iim l-m
A
7/
/
A
1
1/ 1 1
v.
i 1
/
;
N
S.
\pn
\
\\
—-/
\l
\ /
/
/
nn inn 90
\; 5 1
2
1*
3
*o
i
*
s
1
5
6
H
3 7
8
6
3 9
10
0
11
Eggs
12 Weeks
CHART IV. Concurrent variations in blood calcium and whole blood phosphorus in laying pullets.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
the fluctuation in blood calcium, the poorer the egg production of the pullet, regardless of the reason for this poor production. For instance, when Fe 2 (S0 4 ) 8 was fed at a level calculated to combine with half the total phosphorus in the ration as FeP0 4 (Deobald and Elvehjem, 1935) and calcium was allowed ad libitum, egg production virtually ceased and a typical low calcium curve and poor egg production resulted.
BLOOD CALCIUM AND BLOOD PHOSPHORUS IN THE LAYING PULLET
SUMMARY
1. The nature of the rise in blood calcium which occurs as pullets approach maturity is graphically shown by means of bi-weekly analyses of the blood of individual pullets. 2. High blood calcium is not an indication of egg production. Eggs are usually laid during periods of low, constant or descending blood calcium. 3. Changes in blood calcium are associated primarily with spasdomic egg production in the laying pullet. Heavy production is correlated with periods of
little or no variation in the blood calcium. 4. Total phosphorus content of the blood is in direct correlation with the calcium content, except during the initial rise in blood calcium just preceding the laying period. REFERENCES
Buckner, G. D., J. H. Martin, and F. E. Hull, 1930. The distribution of blood calcium in the circulation of laying hens. Am. J. Physiol. 93: 86-89. Buckner, G. D., J. H. Martin, and W. M. Insko, Jr., 1930. The blood calcium of laying hens varied by the calcium intake. Am. J. Physiol. 94:692-695. Common, R. H., 1936. Serum phosphatase in the domestic fowl. J. Agr. Sci. 26:492-508. Deobald, H. J., E. J. Lease, E. B. Hart, and J. G. Halpin, 1936. Studies on the calcium metabolism of laying hens. Poul. Sci. 15:179185. Deobald, H. J., and C. A. Elvehjem, 1935. The effect of feeding high amounts of soluble iron and aluminum salts. Am. J. Physiol. 111:118123. Feinberg, J. H., J. S. Hughes, and H. M. Scott, 1937. Fluctuations of calcium and inorganic phosphorus in the blood of the laying hen during the cycle of one egg. Poul. Sci. 16:132-134. Fiske, C. H., and Y. Subbarow, 1925. The colorimetric determination of phosphorus. J. Biol. Chem. 66:375-400. Greenberg, D. M., C. E. Larson, Paul B. Pearson, and B. R. Burmeister, 1936. The state and partition of the calcium and inorganic phosphorus in the serum of the fowl. Effect of growth and ovulation. Poul. Sci. 15:483-489. MacOwan, Marion, 1932. Observations on the ductless glands, the serum calcium and egg laying in the fowl. Quart. J. Exp. Physiol. 21:383392. Riddle, O., and L. B. Dotti, 1936. Blood calcium in relation to anterior pituitary and sex hormones. Science 84:557-559. Riddle, O., and W. H. Reinhart, 1926. Blood calcium changes in the reproductive cycle. Am. J. Physiol. 76:660-676. Roepke, R. R., and J. S. Hughes, 1935. Phosphorus partition in the blood serum of laying hens. J. Biol. Chem. 108:79-83. Russell, W. C , C. H. Howard, and H. F. Hess, 1930. The relationship in the hen between the development of the ova, blood calcium and the antirachitic factor. Science 72:505-506.
Downloaded from http://ps.oxfordjournals.org/ at University of Southern Queensland on June 20, 2015
cally laying hen, depending entirely upon the time at which the sample is taken. Likewise, in a non-laying pullet, high as well as low blood calcium may result depending on the phase of the cycle at the time the blood is drawn. The observation often made (Greenberg, 1936; MacOwan, 1932) that higher blood calcium is recorded just before egg production, is in general verified by these findings. It is altogether possible, however, to get just as high values for blood calcium in a normally laying pullet producing about 3 eggs per week provided the samples are taken at the various peaks in the blood calcium curve. It is evident that the ovary must function in some way as a regulatory mechanism. The blood calcium is at a fairly uniform level only when the ovary is uniformly active as in a heavily laying bird, or passive as in the immature bird. Riddle (1936) demonstrated a marked rise of blood calcium in pigeons when oestrin was injected. Since the parathyroids (MacOwan, 1932) and the ovaries (Russell, Howard, and Hess, 1930) have already been associated with egg production, and the blood calcium variations are also associated with this change, there is a strong indication that the ovarian hormone, oestrin, is one of the factors responsible for the observed blood calcium and blood phosphorus variations in the laying pullet.
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