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A Comparison of Two Devices for Measuring Egg Shell Thickness1
SEX-REVERSED MALES AND ESTROGENS
Although some of the pullets in the last two hatches did not develop marked shank colour, a white shank colour (as seen in cockerels) did not persist in any of the pullet progeny of the treated parents. DISCUSSION
(1958) and Fraps et al. (1956) can be explained by sex-reversed genetic males among the female progeny. ACKNOWLEDGMENTS
The help of officers and staff of the Poultry Experiment Station under Mr. D. C. Duncan and of Mr. C. R. Sims, chicken sexer, is gratefully acknowledged. REFERENCES Fraps, R. M., H. A. Sohn and M. W. Olsen, 1956. Some effects of multiple pellet implants of diethylstilbestrol in 9 week old chickens. Poultry Sci. 35: 665-668. Pun, C. F., 1958. The sex ratio in the progeny of oestrogen-treated parents in the Brown Leghorn. Poultry Sci. 37: 307-311. Skaller, F., and G. W. Grigg, 1951. The inheritance of shank colour in single-comb White Leghorn and Australorp fowls. Australian J. Agric. Res. 2 : 494-499.
A Comparison of Two Devices for Measuring Egg Shell Thickness 1 Q. B. WELCH, R. E. WAGGONER AND J. C. GILBREATH
Poultry Science Department, Oklahoma State University, Agricultural Experiment Station, Stillwater, Oklahoma (Received for publication October 16, 19S9)
A
T LEAST two devices, a convex anvil • micrometer and a thickness measure guage, have been used to measure egg shell thickness. Recently, however, there seems to be a greater trend toward the use of the paper thickness gauge (Baker and Curtiss, 1958; Kilpatrick et al, 1958). This note concerns an investigation into which device is more precise in obtaining research measurements. Measurements in general can be characterized by: (1) accuracy as defined by 1
Published with the approval of the Director of the Oklahoma State University Agricultural Experiment Station as Journal Article No. 514.
closeness to true value and (2) precision as defined by repeatability. Precision is generally considered to be more important than accuracy. A comparison of two measuring devices for precision in determining egg shell thickness was made. Precision was estimated by correlation. PROCEDURE
The Lufkin convex anvil micrometer and the Ames No. 25E thickness measuring gauge were used. Both instruments are calibrated to 0.001 inches. Three hundred fifty-two individually-marked egg shells with membranes attached were measured for thickness with each device. Each shell
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
It was concluded that oestrogen treatment of hens did not produce pullets that were sex-reversed genetic males. Although the numbers observed here were not large, the present observations considered with those on the 55 pullets tested by Pun (1958), make the probability of occurrence of sex-reversed genetic males very slight (less than one in 165—using only the period of maximum effect of treatment). It is extremely unlikely that sexratios of about 42% as found by Pun
907
908
Q. B. WELCH, R. E. WAGGONER AND J. C. GILBREATH
RESULTS From six measurements, four correlalation coefficients and six means were computed. The mean values are given in Table 1. A set of mutually orthogonal comparisons of the means shown in Table 1 was made. The micrometer wet-measurement mean of 0.0119 inches differs significantly (P < .001) from the thickness gauge wetTABLE 1.—Mean values for six shell thickness measurements
1
Measurement
Mean 1
Micrometer wet Thickness gauge wet First micrometer dry First thickness gauge dry Second micrometer dry Second thickness gauge dry
0.0119 0.0138 0.0129 0.0140 0.0126 0.0142
The mean in inches of 352 readings.
measurement mean of 0.0138 inches. The micrometer dry-measurements vs. gauge dry-measurements comparison is also significant (P < .001). The wet vs. dry comparison for both instruments is significant ( P < .001). The four correlation coefficients are all highly significant (d.f. = 351). The correlation coefficients calculated from the micrometer measurements are as follows: wetmeasurements with the first dry-measurement, r = .854; first dry-measurements with the second dry-measurements, r = .860. The correlation coefficients calculated from the thickness gauge are: wetmeasurements with the first dry-measurements, r = .718; first dry-measurements with the second dry-measurements, r = .759. The two within-instrument, withindry egg shell correlation coefficients (micrometer r = .860, thickness gauge r = .759) differ significantly from each other (P<.01). DISCUSSION AND SUMMARY
Although the same spot was not measured each time on each egg, all measurements were made on the equatorial region of the egg. Olsson (1936) indicated that the shell thickness coefficient of variability is least in the equatorial region. Any discrepancies in location measured would be at random and without bias for either instrument. The two dry measurements on the same egg by the same instrument represent essentially two measurements of the same thing. The correlation between these two measurements will measure the repeatability and, therefore, the precision of the instruments. The r values for the two dry readings for each instrument will provide a direct comparison of their relative precision. The correlation coefficients for the two instruments show that the first micrometer dry measurement is correlated with the second dry measurement, r =
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
was measured three times by each instrument. All measurements were obtained by one operator. The first measurement was made by the Lufkin micrometer as each egg was broken out. The shells were then placed on a water-soaked filler-flat in a closed room. The second measurement was made with the Ames thickness measuring gauge the same day that the first measurement was taken. The egg shells were then moved to a warm, dry, and well-ventilated room. After one week of drying each egg shell was measured two times by each of the two devices on the same day. These four dry measurements were made in the following manner. The first step was to measure the 352 egg shells with the micrometer. All 352 egg shells were then measured with the thickness measuring gauge. This procedure was then repeated in exactly the same manner. The instrument operator was not aware of any previous value for any particular egg shell.
EGG SHELL MEASURING DEVICES
Ames thickness gauge produces an approximately 0.002 inches higher reading than the micrometer under the conditions of this study. It appears that as the egg shell dried out a higher reading was the result with either instrument. This study indicated enough difference between the instruments to warrant reporting which instrument was used in any investigation involving shell thickness. It also indicated that the investigator would probably obtain greater precision by using the micrometer to measure shell thickness. Any delay in measuring shell thickness where membranes are attached could result in higher readings. REFERENCES Baker, R. C , and R. Curtiss, 19S8. Strain differences in egg shell mottling, internal quality, shell thickness, specific gravity and the interrelationship between these factors. Poultry Sci. 37: 1086-1090. Kilpatrick, L., A. W. Brant and H. L. Shrader, 1958. Equipment and methods for measuring egg quality, U.S.D.A., AMS No. 246: 2. Olsson, N., 1936. Studies on some physical and physiological characters in hen's eggs. Sixth World's Poultry Congress Sec. I I : 310-320.
NEWS AND NOTES (Continued from page 905) use of micro-crystalline wax. Potency 250,000 I.U. per gram." It would appear that an error was made, by the company concerned, in supplying this product, and that the product tested was for pharmaceutical use and was "oil in complex carbohydrate type carrier-vitamin A feeding oil blended with wheat germ meal and soybean oil meal. The oil was blended into carrier by a process involving the use of a complex carbohydrate-type material. Potency 250,000 I.U. per gram." CALIFORNIA NOTES Two poultry scientists of the University of California, Davis, have been awarded Guggenheim Fellowships for special studies abroad, beginning in August. C. R. Grau will go to Strangeways Research Laboratory in Cambridge, England, to work with
Dr. H. B. Fell, a pioneer worker in the culture of isolated animal organs. He will study nutritional problems and special techniques to use in his work on embryonic nutrition. Ursula K. Abbott will study at the Poultry Research Centre and the Animal Genetics Institute in Edinburgh, Scotland; the laboratory of Professor Etienne Wolff at the College de France, Paris; and the laboratory of Professor R. Amprino in Bari, Italy. She will examine techniques and have access to specimen collections attached to these laboratories, an aid in completing her book describing and analyzing abnormalities in the development of birds. IOWA NOTES
Dr. John C. Ayres, Department of Dairy and Food Industry, Iowa State University of Science and Technology, Ames, has received an award (Continued on page 937)
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
.860, while the first thickness gauge dry measurement is correlated with the second thickness gauge dry measurement, r = .759. This indicates that the micrometer may be more precise then the thickness measuring gauge, and that fewer replications are required to get the same information. The significantly higher reading obtained by the thickness gauge over the micrometer for the wet readings could represent either a difference in the devices or a difference in the shell. A change in the shell environment had occurred. The shells and membranes were in the presence of moist air instead of around the albumen. The significant increase in thickness from the wet to the dry condition for both devices indicates that the dry egg shell is thicker. This increase may be due to a thickening of the shell membrane, a loss of resiliency, or both. The four dry readings were made under similar conditions, except for the instrument difference. The significant difference between instruments indicates that the
909
Although some of the pullets in the last two hatches did not develop marked shank colour, a white shank colour (as seen in cockerels) did not persist in any of the pullet progeny of the treated parents. DISCUSSION
(1958) and Fraps et al. (1956) can be explained by sex-reversed genetic males among the female progeny. ACKNOWLEDGMENTS
The help of officers and staff of the Poultry Experiment Station under Mr. D. C. Duncan and of Mr. C. R. Sims, chicken sexer, is gratefully acknowledged. REFERENCES Fraps, R. M., H. A. Sohn and M. W. Olsen, 1956. Some effects of multiple pellet implants of diethylstilbestrol in 9 week old chickens. Poultry Sci. 35: 665-668. Pun, C. F., 1958. The sex ratio in the progeny of oestrogen-treated parents in the Brown Leghorn. Poultry Sci. 37: 307-311. Skaller, F., and G. W. Grigg, 1951. The inheritance of shank colour in single-comb White Leghorn and Australorp fowls. Australian J. Agric. Res. 2 : 494-499.
A Comparison of Two Devices for Measuring Egg Shell Thickness 1 Q. B. WELCH, R. E. WAGGONER AND J. C. GILBREATH
Poultry Science Department, Oklahoma State University, Agricultural Experiment Station, Stillwater, Oklahoma (Received for publication October 16, 19S9)
A
T LEAST two devices, a convex anvil • micrometer and a thickness measure guage, have been used to measure egg shell thickness. Recently, however, there seems to be a greater trend toward the use of the paper thickness gauge (Baker and Curtiss, 1958; Kilpatrick et al, 1958). This note concerns an investigation into which device is more precise in obtaining research measurements. Measurements in general can be characterized by: (1) accuracy as defined by 1
Published with the approval of the Director of the Oklahoma State University Agricultural Experiment Station as Journal Article No. 514.
closeness to true value and (2) precision as defined by repeatability. Precision is generally considered to be more important than accuracy. A comparison of two measuring devices for precision in determining egg shell thickness was made. Precision was estimated by correlation. PROCEDURE
The Lufkin convex anvil micrometer and the Ames No. 25E thickness measuring gauge were used. Both instruments are calibrated to 0.001 inches. Three hundred fifty-two individually-marked egg shells with membranes attached were measured for thickness with each device. Each shell
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
It was concluded that oestrogen treatment of hens did not produce pullets that were sex-reversed genetic males. Although the numbers observed here were not large, the present observations considered with those on the 55 pullets tested by Pun (1958), make the probability of occurrence of sex-reversed genetic males very slight (less than one in 165—using only the period of maximum effect of treatment). It is extremely unlikely that sexratios of about 42% as found by Pun
907
908
Q. B. WELCH, R. E. WAGGONER AND J. C. GILBREATH
RESULTS From six measurements, four correlalation coefficients and six means were computed. The mean values are given in Table 1. A set of mutually orthogonal comparisons of the means shown in Table 1 was made. The micrometer wet-measurement mean of 0.0119 inches differs significantly (P < .001) from the thickness gauge wetTABLE 1.—Mean values for six shell thickness measurements
1
Measurement
Mean 1
Micrometer wet Thickness gauge wet First micrometer dry First thickness gauge dry Second micrometer dry Second thickness gauge dry
0.0119 0.0138 0.0129 0.0140 0.0126 0.0142
The mean in inches of 352 readings.
measurement mean of 0.0138 inches. The micrometer dry-measurements vs. gauge dry-measurements comparison is also significant (P < .001). The wet vs. dry comparison for both instruments is significant ( P < .001). The four correlation coefficients are all highly significant (d.f. = 351). The correlation coefficients calculated from the micrometer measurements are as follows: wetmeasurements with the first dry-measurement, r = .854; first dry-measurements with the second dry-measurements, r = .860. The correlation coefficients calculated from the thickness gauge are: wetmeasurements with the first dry-measurements, r = .718; first dry-measurements with the second dry-measurements, r = .759. The two within-instrument, withindry egg shell correlation coefficients (micrometer r = .860, thickness gauge r = .759) differ significantly from each other (P<.01). DISCUSSION AND SUMMARY
Although the same spot was not measured each time on each egg, all measurements were made on the equatorial region of the egg. Olsson (1936) indicated that the shell thickness coefficient of variability is least in the equatorial region. Any discrepancies in location measured would be at random and without bias for either instrument. The two dry measurements on the same egg by the same instrument represent essentially two measurements of the same thing. The correlation between these two measurements will measure the repeatability and, therefore, the precision of the instruments. The r values for the two dry readings for each instrument will provide a direct comparison of their relative precision. The correlation coefficients for the two instruments show that the first micrometer dry measurement is correlated with the second dry measurement, r =
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
was measured three times by each instrument. All measurements were obtained by one operator. The first measurement was made by the Lufkin micrometer as each egg was broken out. The shells were then placed on a water-soaked filler-flat in a closed room. The second measurement was made with the Ames thickness measuring gauge the same day that the first measurement was taken. The egg shells were then moved to a warm, dry, and well-ventilated room. After one week of drying each egg shell was measured two times by each of the two devices on the same day. These four dry measurements were made in the following manner. The first step was to measure the 352 egg shells with the micrometer. All 352 egg shells were then measured with the thickness measuring gauge. This procedure was then repeated in exactly the same manner. The instrument operator was not aware of any previous value for any particular egg shell.
EGG SHELL MEASURING DEVICES
Ames thickness gauge produces an approximately 0.002 inches higher reading than the micrometer under the conditions of this study. It appears that as the egg shell dried out a higher reading was the result with either instrument. This study indicated enough difference between the instruments to warrant reporting which instrument was used in any investigation involving shell thickness. It also indicated that the investigator would probably obtain greater precision by using the micrometer to measure shell thickness. Any delay in measuring shell thickness where membranes are attached could result in higher readings. REFERENCES Baker, R. C , and R. Curtiss, 19S8. Strain differences in egg shell mottling, internal quality, shell thickness, specific gravity and the interrelationship between these factors. Poultry Sci. 37: 1086-1090. Kilpatrick, L., A. W. Brant and H. L. Shrader, 1958. Equipment and methods for measuring egg quality, U.S.D.A., AMS No. 246: 2. Olsson, N., 1936. Studies on some physical and physiological characters in hen's eggs. Sixth World's Poultry Congress Sec. I I : 310-320.
NEWS AND NOTES (Continued from page 905) use of micro-crystalline wax. Potency 250,000 I.U. per gram." It would appear that an error was made, by the company concerned, in supplying this product, and that the product tested was for pharmaceutical use and was "oil in complex carbohydrate type carrier-vitamin A feeding oil blended with wheat germ meal and soybean oil meal. The oil was blended into carrier by a process involving the use of a complex carbohydrate-type material. Potency 250,000 I.U. per gram." CALIFORNIA NOTES Two poultry scientists of the University of California, Davis, have been awarded Guggenheim Fellowships for special studies abroad, beginning in August. C. R. Grau will go to Strangeways Research Laboratory in Cambridge, England, to work with
Dr. H. B. Fell, a pioneer worker in the culture of isolated animal organs. He will study nutritional problems and special techniques to use in his work on embryonic nutrition. Ursula K. Abbott will study at the Poultry Research Centre and the Animal Genetics Institute in Edinburgh, Scotland; the laboratory of Professor Etienne Wolff at the College de France, Paris; and the laboratory of Professor R. Amprino in Bari, Italy. She will examine techniques and have access to specimen collections attached to these laboratories, an aid in completing her book describing and analyzing abnormalities in the development of birds. IOWA NOTES
Dr. John C. Ayres, Department of Dairy and Food Industry, Iowa State University of Science and Technology, Ames, has received an award (Continued on page 937)
Downloaded from http://ps.oxfordjournals.org/ at Universite de Sherbrooke on May 5, 2015
.860, while the first thickness gauge dry measurement is correlated with the second thickness gauge dry measurement, r = .759. This indicates that the micrometer may be more precise then the thickness measuring gauge, and that fewer replications are required to get the same information. The significantly higher reading obtained by the thickness gauge over the micrometer for the wet readings could represent either a difference in the devices or a difference in the shell. A change in the shell environment had occurred. The shells and membranes were in the presence of moist air instead of around the albumen. The significant increase in thickness from the wet to the dry condition for both devices indicates that the dry egg shell is thicker. This increase may be due to a thickening of the shell membrane, a loss of resiliency, or both. The four dry readings were made under similar conditions, except for the instrument difference. The significant difference between instruments indicates that the
909