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Relationship of Blood Pressure of Hens to Blood Spot Incidence in the Eggs1
RESEARCH NOTES
tion is the appropriate error term for testing strains it is possible if the replicates within strains are weighed at different times, for the strain mean square to be biased upward and the interaction mean square to be biased downward so that strain differences appear to be significant when in fact they are not. In order to minimize the bias in body weight estimation due to the presence of an egg, one could attempt to weigh all birds after they have laid or alternatively one could palpate each bird and adjust for egg weight if an egg is present. The bias due to egg weight is of far less importance in the larger species such as the chicken or turkey where the egg weight represents a small percentage of body weight. In a bird such as the Japanese quail, where egg weight represents about seven percent of body weight, the bias could be very serious.
RELATIONSHIP OF BLOOD PRESSURE OF HENS TO BLOOD SPOT INCIDENCE IN THE EGGS1 JACK L. FEY, HENRY R. WILSON AND GEORGE M. HERRICK
Florida Agricultural Experiment Stations, Gainesville, Florida 32601 (Received for publication August 14, 1968)
It is an accepted fact that heredity is an important factor in limiting the incidence of blood spots in eggs of commercial strains of chickens. However, about one percent of all commercially candled eggs are removed from market channels because of blood spots. On a broken-out basis, total blood spot percentages ranged from 2.71 to 5.41 for the commercial strains entered in the 15th Florida Random Sample Test (O'Steen et al., 1968). The differences in blood spot incidence 'Florida Agr. Exp. Sta. Journal Series No. 3027.
in eggs are theoretically due to differences in (1) capillary fragility, (2) blood clotting time and (3) blood pressure. Bigland et al. (1964) reported that injected chalcones, which reduce capillary fragility, significantly reduced the percentages of blood spots. Siddiqui and Fry (1963), using Warfarin, and Waldroup and Harms (1962) and Day et al. (1964), using dicumarol, found that these anticoagulants in the diets of laying hens increased the clotting or prothrombin time and decreased the incidence of blood spots. The visible presence of blood in eggs was also decreased by low levels of vitamin K (Fry et al., 1968).
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on May 4, 2015
weighed in the morning so that a large percentage of the birds had an egg in the oviduct and the lighter group were weighed in the afternoon when few birds had an egg, the difference in body weight which is in reality non-significant (1736 vs. 1759) would appear to be highly significant (1736 < 1812). If the group of birds with smaller body weight were weighed in the morning and the heavier group in the afternoon the mean of the lighter group would appear to be greater than that of the heavier group (Xi vs. Xn) but not significantly so. The difference in the means of the Set II and Set II' birds was not significant due to the smaller number of birds in this comparison. When several strains of birds are compared, the possible effects of bias can become quite complex. For example, in the situation where the comparison is replicated and the strain by replicate interac-
1639
1640
RESEARCH NOTES
the eggs laid by individual hens in the 16 day period and averaged 46.9%. The correlation coefficients were as follows:
EXPERIMENTAL
Blood pressure Percentage of blood spots, + .156 Blood pressure Average blood spot score, + .159 Blood pressure Average score of eggs containing blood, + .096
The birds used were a high blood spot incidence strain initially selected by the Western Washington Experiment Station (Puyallup) and maintained since 1965 at the Florida station. The hens were individually caged and fed a commercial type corn-soybean diet. The blood spot incidence for each of 223 hens was determined by breaking out all of their eggs for a period of 16 days. The yolk of each egg was removed from the albumen and its entire surface carefully examined for the presence of blood. The eggs were scored as follows, based on the maximum dimension of the largest single inclusion of blood: 0—no blood; 1—re" or less; 2— 16
ro
] 6
, i
16
tO -2 , t
P» 2
! •>
bloody albumen. The systolic blood pressure was determined for each hen by the indirect method using a Physiograph-Six*. The cuff (4 cm. wide) was placed on the distal end of the tibia and the pneumatic pulse pick-up on the artery passing over the hock joint. Three pressure measurements were made per bird and the average pressure used in subsequent calculations. The blood pressures were then correlated with (1) the percentage of blood spots, (2) average score (numerical total for each hen divided by total number of eggs examined for that hen) and (3) average score of eggs containing blood (numerical total for each hen divided by total number of eggs containing blood). RESULTS AND DISCUSSION Blood pressures ranged from 70 to 175 mm. Hg for the hens tested. Blood spot percentages ranged from 0 to 100% of all * Manufactured by E & M Instruments Co., Inc., Houston, Texas.
The values of .156 and .159 were statistically significant (P<.05). Although the correlation coefficients are not as large as might have been expected the fact that they are all positive indicates that blood pressure is a factor in blood spot incidence and blood spot size. The use of certain drugs (and possibly genetic selection) to lower blood pressure and reduce capillary fragility may provide a means of further reduction in bloodspot incidence. REFERENCES Bigland, C. H., E. B. Bennett and U. K. Abbott, 1964. Decrease in incidence of blood spots in chicken eggs by injection derivatives of pyrrole-2-aldehyde chalcones into hens. Proc. Soc. Exp. Biol. Med. 116: 1122-1125. Day, E. J., B. C. Dilworth and P. N. Dua, 1964. Reduced incidence of blood spots in eggs with dicumarol supplementation. Poultry Sci. 4 3 : 796-798. Fry, J. L., P. W. Waldroup, B. L. Damron, R. H. Harms and H. R. Wilson, 1968. Relationship of dietary menadione sodium bisulfite complex (MSBC) and vitamin A to blood spot incidence and prothrombin time of laying hens. Poultry Sci. 47 : 630-634. O'Steen, A. W., J. S. Moore, L. W. Kalch and R. H. Harms, 1968. Florida Random Sample Test, summary, fifteenth year. Agricultural Extension Service, University of Florida. Siddiqui, S. M., and J. L. Fry, 1963. Studies with Warfarin on the incidence of blood spots and in relation to prothrombin time, egg quality and mortality in laying hens. Poultry Sci. 42: 1125-1130. Waldroup, P. W., and R. H. Harms, 1962. The influence of dicumarol on the incidence of blood spots in eggs. Poultry Sci. 4 1 : 510-512.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on May 4, 2015
This paper reports the results of studies of the relationships of blood pressure and blood spot incidence.
tion is the appropriate error term for testing strains it is possible if the replicates within strains are weighed at different times, for the strain mean square to be biased upward and the interaction mean square to be biased downward so that strain differences appear to be significant when in fact they are not. In order to minimize the bias in body weight estimation due to the presence of an egg, one could attempt to weigh all birds after they have laid or alternatively one could palpate each bird and adjust for egg weight if an egg is present. The bias due to egg weight is of far less importance in the larger species such as the chicken or turkey where the egg weight represents a small percentage of body weight. In a bird such as the Japanese quail, where egg weight represents about seven percent of body weight, the bias could be very serious.
RELATIONSHIP OF BLOOD PRESSURE OF HENS TO BLOOD SPOT INCIDENCE IN THE EGGS1 JACK L. FEY, HENRY R. WILSON AND GEORGE M. HERRICK
Florida Agricultural Experiment Stations, Gainesville, Florida 32601 (Received for publication August 14, 1968)
It is an accepted fact that heredity is an important factor in limiting the incidence of blood spots in eggs of commercial strains of chickens. However, about one percent of all commercially candled eggs are removed from market channels because of blood spots. On a broken-out basis, total blood spot percentages ranged from 2.71 to 5.41 for the commercial strains entered in the 15th Florida Random Sample Test (O'Steen et al., 1968). The differences in blood spot incidence 'Florida Agr. Exp. Sta. Journal Series No. 3027.
in eggs are theoretically due to differences in (1) capillary fragility, (2) blood clotting time and (3) blood pressure. Bigland et al. (1964) reported that injected chalcones, which reduce capillary fragility, significantly reduced the percentages of blood spots. Siddiqui and Fry (1963), using Warfarin, and Waldroup and Harms (1962) and Day et al. (1964), using dicumarol, found that these anticoagulants in the diets of laying hens increased the clotting or prothrombin time and decreased the incidence of blood spots. The visible presence of blood in eggs was also decreased by low levels of vitamin K (Fry et al., 1968).
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on May 4, 2015
weighed in the morning so that a large percentage of the birds had an egg in the oviduct and the lighter group were weighed in the afternoon when few birds had an egg, the difference in body weight which is in reality non-significant (1736 vs. 1759) would appear to be highly significant (1736 < 1812). If the group of birds with smaller body weight were weighed in the morning and the heavier group in the afternoon the mean of the lighter group would appear to be greater than that of the heavier group (Xi vs. Xn) but not significantly so. The difference in the means of the Set II and Set II' birds was not significant due to the smaller number of birds in this comparison. When several strains of birds are compared, the possible effects of bias can become quite complex. For example, in the situation where the comparison is replicated and the strain by replicate interac-
1639
1640
RESEARCH NOTES
the eggs laid by individual hens in the 16 day period and averaged 46.9%. The correlation coefficients were as follows:
EXPERIMENTAL
Blood pressure Percentage of blood spots, + .156 Blood pressure Average blood spot score, + .159 Blood pressure Average score of eggs containing blood, + .096
The birds used were a high blood spot incidence strain initially selected by the Western Washington Experiment Station (Puyallup) and maintained since 1965 at the Florida station. The hens were individually caged and fed a commercial type corn-soybean diet. The blood spot incidence for each of 223 hens was determined by breaking out all of their eggs for a period of 16 days. The yolk of each egg was removed from the albumen and its entire surface carefully examined for the presence of blood. The eggs were scored as follows, based on the maximum dimension of the largest single inclusion of blood: 0—no blood; 1—re" or less; 2— 16
ro
] 6
, i
16
tO -2 , t
P» 2
! •>
bloody albumen. The systolic blood pressure was determined for each hen by the indirect method using a Physiograph-Six*. The cuff (4 cm. wide) was placed on the distal end of the tibia and the pneumatic pulse pick-up on the artery passing over the hock joint. Three pressure measurements were made per bird and the average pressure used in subsequent calculations. The blood pressures were then correlated with (1) the percentage of blood spots, (2) average score (numerical total for each hen divided by total number of eggs examined for that hen) and (3) average score of eggs containing blood (numerical total for each hen divided by total number of eggs containing blood). RESULTS AND DISCUSSION Blood pressures ranged from 70 to 175 mm. Hg for the hens tested. Blood spot percentages ranged from 0 to 100% of all * Manufactured by E & M Instruments Co., Inc., Houston, Texas.
The values of .156 and .159 were statistically significant (P<.05). Although the correlation coefficients are not as large as might have been expected the fact that they are all positive indicates that blood pressure is a factor in blood spot incidence and blood spot size. The use of certain drugs (and possibly genetic selection) to lower blood pressure and reduce capillary fragility may provide a means of further reduction in bloodspot incidence. REFERENCES Bigland, C. H., E. B. Bennett and U. K. Abbott, 1964. Decrease in incidence of blood spots in chicken eggs by injection derivatives of pyrrole-2-aldehyde chalcones into hens. Proc. Soc. Exp. Biol. Med. 116: 1122-1125. Day, E. J., B. C. Dilworth and P. N. Dua, 1964. Reduced incidence of blood spots in eggs with dicumarol supplementation. Poultry Sci. 4 3 : 796-798. Fry, J. L., P. W. Waldroup, B. L. Damron, R. H. Harms and H. R. Wilson, 1968. Relationship of dietary menadione sodium bisulfite complex (MSBC) and vitamin A to blood spot incidence and prothrombin time of laying hens. Poultry Sci. 47 : 630-634. O'Steen, A. W., J. S. Moore, L. W. Kalch and R. H. Harms, 1968. Florida Random Sample Test, summary, fifteenth year. Agricultural Extension Service, University of Florida. Siddiqui, S. M., and J. L. Fry, 1963. Studies with Warfarin on the incidence of blood spots and in relation to prothrombin time, egg quality and mortality in laying hens. Poultry Sci. 42: 1125-1130. Waldroup, P. W., and R. H. Harms, 1962. The influence of dicumarol on the incidence of blood spots in eggs. Poultry Sci. 4 1 : 510-512.
Downloaded from http://ps.oxfordjournals.org/ at Uniwersytet Warszawski Biblioteka Uniwersytecka on May 4, 2015
This paper reports the results of studies of the relationships of blood pressure and blood spot incidence.