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The Influence of Quantity of Thick Albumen on Internal Egg Quality Measurements
LARGE WHITE TURKEY CHARACTERISTICS
Carcass quality of turkeys as affected by estradiol-17 beta-monopalmitate and vitamin E. 2. Effect on young torn turkeys. Poultry Sci. 47: 1493-1496. Robblee, A. R., A. B. Morrison and D. R. Clandinin, 1951. The use of thiouracil and diethylstilbesterol for finishing turkeys. Poultry Sci. 30: 772-774. Scott, M. L., 1969. 1969 growth rate and feed consumption standards. Turkey World, p. 33. Smyth, J. R., Jr., D. L. Anderson and R. E. Gleason, 1961. The residual effect of diethylstilbesterol on fat finish in turkeys. Poultry Sci. 40: 265-266. Swanson, M. H., C. W. Carlson and J. L. Fry, 1964. Factors affecting poultry meat yields. Minnesota Agric. Expt. Station Bull. #476. 36 pp. Winter, A. R., and P. Clements, 1957. Cooked edible meat and ready-to-cook poultry. J. Am. Dietetic Assoc. 33:800-802.
The Influence of Quantity of Thick Albumen on Internal Egg Quality Measurements R. C. BAKER AND D. V. VADEHRA Department of Poultry Science, Cornell University, Ithaca, N. Y. 14850 (Received for publication October 16, 1969)
GREAT deal of attention is given to the internal quality of eggs because of economics, appearance and consumption. In the past there have been many discussions as to whether internal quality as measured by U.S.D.A. scores or Haugh units is directly related to the percent of thick albumen or due to the placement of the thick white. There isn't enough information in the literature to accurately make a decision on the influence of amount of firm albumen on internal egg quality.
A
REVIEW OF LITERATURE
Lorenz et al. (1931) found that the amount of thick white was an inherited factor. They also stated that eggs with high original percent firm white were superior for storage purposes. Knox et al. (1931) showed that Leghorns as a breed
produced more thick albumen in their eggs than did Rhode Island Reds. They found that egg weight was correlated with thick albumen weight but not with percent thick albumen. Sauter et al. (1953) studied the relationship of candled quality of eggs to other quality measurements. They found that there was a highly significant correlation between candling quality and albumen index, yolk index, yolk color, albumen scores and pH. Wesley and Stadelman (1959) compared several internal egg quality measurements. They found that percent thick albumen was correlated with thin albumen diameter (r= —0.64), thick albumen diameter (r = +0.93), yolk index ( 4 = - 0 . 7 2 ) and Haugh units (r=— 0.86). The authors concluded that percent thick albumen was
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
for the large white turkey on live performance and carcass quality with a note on the correlation of back skin fat and grade of finish. Brit. Poultry Sci. 19: 127-138. Moreng, R. E., W. A. Whittel and H. L. Enos, 1963. Studies on turkey body composition. 1. Increasing carcass fat and finish by administration of diethylstilbesterol and the estimation of carcass fat using specific gravity. Poultry Sci. 42: 259267. Moreng, R. E., and M. L. Hopwood, 1966. The effect of a single subcutaneous injection of estradiol-17beta-monopalmitate on growth in turkeys. Poultry Sci. 45:829-833. Osborn, W. E., R. E. Moreng and T. E. Hartung, 1969. Turkey lipid characteristics: influence of sex, age and estradiol-17 beta-monopalmitate. Poultry Sci. 48: 274-283. Pickett, L. D., B. F . Miller and R. E. Moreng, 1968.
493
494
R. C. BAKER AND D. V. VADEHRA
layer. MATERIALS AND METHODS
Twenty-five one day old eggs from each of ten different strains of chickens were used in this study. The eggs were stored at 13°C. before using. The study was carried out in May of 1968 and repeated in July of the same year. Of the ten strains five strains (heavies) laid brown eggs and five strains (White Leghorns) laid white eggs. U.S.D.A. scores were determined by one person while Haugh units were measured by another. The percent thick albumen was determined as follows: The shelled eggs were weighed in grams and then broken out. The weight of the shell, membranes, and the residual albumen was deducted from the weight of the shelled egg. The yolks (including the chalaziferous layer and chalazae) were separated and the albumen was placed on a 16 mm. mesh screen over a beaker. The thick albumen
(middle thick) was cut several times with a knife to allow the inner thin white to drain. The outer and inner thin albumen passed through the screen and the percent thick albumen was determined by dividing the weight of the thick albumen by the weight of the total internal egg contents including the yolk. One minute was allowed for the thin albumen to pass through the screen, and this was found adequate for complete separation. Percent thick albumen in this study is not the same as reported by Lorenz et al. (1931), Wesley and Stadelman (1959) and Skala and Swanson (1962a) since they determined the percent thick white based only on total albumen. RESULTS AND DISCUSSION
The data on the egg quality measurements is summarized in Table 1. Analysis of variance was used to test significance on values obtained for three internal quality factors. The percent thick albumen was highly significantly different (P < .01) among the strains. This agrees with Lorenz et al. (1931) who found that the amount of thick albumen was an inherited factor. The eggs from the heavy breeds did not differ significantly from the Leghorns TABLE 1.—Average values for egg quality measurements for ten strains of chickens1 E ^S color
A B C D E F G H I J 1
White White White White White Brown Brown Brown Brown Brown
a ll b^u e m
n U.S.D.A. ^' scores percent
Haugh units
36.80 cd 2 3 . 9 4 ^ 7 5 . 5 2 ^ 39.78 a 3.66 ab 7'7.74abc 39.1(U 3.46 a 79.02 a 3S.96Cde 4.06 cd 74.56 bcd 34.02 e 3.66 ab 77.98 ab 37.86 abcd 4 . 0 4 ^ 74.52 cd 35.90^ 4.16 d 73.64 d 38.18ab« 4.00 bcd 74.64 bcd 38.19ab= 3.70 abo 77.82 abo 37.24bcd 4.02 bod 7 4 . 7 0 ^
Each figure average of SO eggs. Means followed by the same letter subscript are not significantly different from each other (5% level). 2
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
not as good an indicator of internal quality as some other measurements. The eggs used for their work apparently were all from one strain of chickens. Skala and Swanson (1962a) studied the variation in initial quality of eggs. They selected hens within a strain that laid high quality eggs and compared them to hens in the same strain that laid poor quality eggs. They found that the higher quality eggs were heavier and contained a larger amount of total white than did the lower quality eggs. They also found that the total white of the high quality eggs contained a significantly higher percentage of thick white and a lower percentage of weight of outer thin white than did the lower quality eggs. Skala and Swanson (1962b) in a continuing study found the whole whites and the middle thick and inner thin white layers from the higher quality eggs contained higher concentrations of total solids and total nitrogen, but this was not true of the outer thin
495
THICK ALBUMEN AND EGG QUALITY
TABLE 2.—Ranking of egg quality measurements for ten strains E
Strain
?g color
A B C D E F G H I
White White White White White Brown Brown Brown Brown Brown
J
Thick albumen' .' percent 7 1 2 8 10 5 9 4 3 6
* i =: best, 10 = poorest.
5 3 1 9 2 8 10 6 4 7
5 4 1 8 2 9 10 7 3 6
TABLE 3.—Correlation coefficient values of percent thick albumen and internal quality measurements
Strain Egg color
Correlation coefficients between percent thick albumen and U.S.D.A. scores Haugh units
A B C D E F G H I
J
White White White White White Brown Brown Brown Brown Brown
—0.573 -0.361 -0.373 -0.552 -0.423 -0.370 -0.601 -0.653 -0.600 -0.546
+0.695 +0.453 +0.477 +0.563 +0.386 +0.333 +0.521 +0.665 +0.650 +0.682
of thick albumen and yet had internal egg quality measurements which ranked second. Apparently, in Strain E the thick albumen is so placed that it gives the appearance of good quality eggs. Correlation coefficients were run on percent thick albumen and U.S.D.A. scores and also on percent thick albumen and Haugh units (Table 3). All of the correlation coefficients were highly significant but not high enough to conclude that the amount of thick white had an appreciable effect upon U.S.D.A. scores or Haugh units. Even with the higher correlation coefficients, only approximately 40 percent of internal egg quality measurements could be accounted for by the amount of thick albumen. In some of the strains as low as ten percent of the internal quality determination could be accounted for by the percent of firm albumen. Some other factor or factors must influence the internal egg quality determinations. It would appear that the shape of the firm albumen envelope (upstanding or flattened) when the egg is broken-out is more important than the actual amount. I t is also possible that the relative position of the yolk (centered or not centered) may influence the height of the thick albumen and thus affect the measurement. The average of the "r" values for per-
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
which seems to disagree with the findings of Knox et al. (1931) who found that White Leghorns as a breed had more thick albumen in their eggs than Rhode Island Reds. U.S.D.A. scores were significantly (P < .01) different for the various strains and also for Leghorns as compared to heavies. The U.S.D.A. scores were superior for the strains that laid white eggs. This is somewhat surprising since the percent thick albumen did not differ significantly. This would indicate that this scoring system was not totally dependent on percent thick albumen. Haugh units also differed significantly (P<.01) among the strains and between Leghorns and heavies. In this study, with all three internal quality measurements, the replications were not significantly different nor were treatments times replications. Duncan's new multiple range test was used to determine significances among the means (Table 1). The averages of the figures for the three egg quality measurements were ranked for comparison and the results are shown in Table 2. In most cases there was a fair agreement between percent thick albumen and internal egg quality scores. There was one major exception in Strain E, however, in that these eggs had the lowest percent
496
R. C. BAKER AND D. V. VADEHRA
SUMMARY
Percent thick albumen was highly significantly different (P<.01) among the strains but not different between Leghorns and heavy breeds. U.S.D.A. scores and Haugh units
showed highly significant differences (P <.01) among the strains and between Leghorns and heavy breeds. Correlation coefficients for percent thick albumen and U.S.D.A. scores were low as was the case for percent thick albumen and Haugh units. Position of the thick albumen relative to the yolk is undoubtedly more important than the actual amount in determining internal quality by the use of U.S.D.A. scores or Haugh units. REFERENCES Knox, C. W., and A. B. Godfrey, 1931. Variability of thick albumen in fresh-laid eggs. Poultry Sci. 13: 18-24. Lorenz, F. W., L. W. Taylor and H. J. Almquist, 1931. Firmness of albumen as an inherited characteristic. Poultry Sci. 13: 14-17. Sauter, E. A., J. V. Harns and W. J. Stadelman, 1953. Relationship of candled quality of eggs to other quality measurements. Poultry Sci. 32: 850-854. Skala, J. H., and M. H. Swanson, 1962a. Studies of variation in initial quality of chicken eggs. 1. Physical measurements of albumen and yolks. Poultry Sci. 41: 1533-1536. Skala, J. H., and M. H. Swanson, 1962b. Studies of variation in initial quality of chicken eggs. 2. Chemical properties of the albumen. Poultry Sci. 41: 1537-1545. Wesley, R. L., and W. J. Stadelman, 1959. Measurements of interior quality. Poultry Sci. 38: 474481.
NEWS AND NOTES {Continued from page 458) 1. Stick closely to the time allotted if you don't want the chairman to cut you off. Rehearse your speech. Take whatever steps you must to provide a margin of 1-2 minutes. This fosters your popularity and intelligent discussion from the floor. 2. If possible, do not read your manuscript. Know your material, and make it sound extemporaneous. 3. Do not show more than 3 slides in 5 minutes of speaking time. Slides must be intelligible, even to those who cannot hear what you are saying. They must be properly marked, not overcrowded, and of
course, legible. Don't show photographs of tables taken from published papers. They are seldom clear enough, and usually contain more than can be absorbed during a speech. If abbreviations must be used, explain them. 4. When showing slides, talk to the audience not the screen. If the slides need comment, have a copy in front of you. Use a pointer only a minimum. Remember, you are not transparent. 5. Time is precious. Some formalities may be omitted or pared ruthlessly: (a) all but the briefest historical introduction; (b) bibliographical refer-
{Continued on page 522)
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
cent firm albumen and U.S.D.A. scores was higher for the heavies ( — 0.554) than for the Leghorns ( — 0.456). This is not great but certainly worth noting. The average of the "r" values for percent thick albumen when related to Haugh units was also greater for the heavies (+.570) than for the Leghorns (+0.515). It is generally agreed among people who candle eggs that there isn't always a good agreement between the candling score of eggs and the internal quality measurements such as U.S D.A. scores and Haugh units. This is supported by Sauter et al. (1953). Eggs from certain strains of chickens will look better when candled than their actual "break out" appearance or vice versa. The results of this study can offer an explanation for this since percent thick white is far from being the sole factor influencing internal egg quality measurements and the quantity of firm albumen should influence candling.
Carcass quality of turkeys as affected by estradiol-17 beta-monopalmitate and vitamin E. 2. Effect on young torn turkeys. Poultry Sci. 47: 1493-1496. Robblee, A. R., A. B. Morrison and D. R. Clandinin, 1951. The use of thiouracil and diethylstilbesterol for finishing turkeys. Poultry Sci. 30: 772-774. Scott, M. L., 1969. 1969 growth rate and feed consumption standards. Turkey World, p. 33. Smyth, J. R., Jr., D. L. Anderson and R. E. Gleason, 1961. The residual effect of diethylstilbesterol on fat finish in turkeys. Poultry Sci. 40: 265-266. Swanson, M. H., C. W. Carlson and J. L. Fry, 1964. Factors affecting poultry meat yields. Minnesota Agric. Expt. Station Bull. #476. 36 pp. Winter, A. R., and P. Clements, 1957. Cooked edible meat and ready-to-cook poultry. J. Am. Dietetic Assoc. 33:800-802.
The Influence of Quantity of Thick Albumen on Internal Egg Quality Measurements R. C. BAKER AND D. V. VADEHRA Department of Poultry Science, Cornell University, Ithaca, N. Y. 14850 (Received for publication October 16, 1969)
GREAT deal of attention is given to the internal quality of eggs because of economics, appearance and consumption. In the past there have been many discussions as to whether internal quality as measured by U.S.D.A. scores or Haugh units is directly related to the percent of thick albumen or due to the placement of the thick white. There isn't enough information in the literature to accurately make a decision on the influence of amount of firm albumen on internal egg quality.
A
REVIEW OF LITERATURE
Lorenz et al. (1931) found that the amount of thick white was an inherited factor. They also stated that eggs with high original percent firm white were superior for storage purposes. Knox et al. (1931) showed that Leghorns as a breed
produced more thick albumen in their eggs than did Rhode Island Reds. They found that egg weight was correlated with thick albumen weight but not with percent thick albumen. Sauter et al. (1953) studied the relationship of candled quality of eggs to other quality measurements. They found that there was a highly significant correlation between candling quality and albumen index, yolk index, yolk color, albumen scores and pH. Wesley and Stadelman (1959) compared several internal egg quality measurements. They found that percent thick albumen was correlated with thin albumen diameter (r= —0.64), thick albumen diameter (r = +0.93), yolk index ( 4 = - 0 . 7 2 ) and Haugh units (r=— 0.86). The authors concluded that percent thick albumen was
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
for the large white turkey on live performance and carcass quality with a note on the correlation of back skin fat and grade of finish. Brit. Poultry Sci. 19: 127-138. Moreng, R. E., W. A. Whittel and H. L. Enos, 1963. Studies on turkey body composition. 1. Increasing carcass fat and finish by administration of diethylstilbesterol and the estimation of carcass fat using specific gravity. Poultry Sci. 42: 259267. Moreng, R. E., and M. L. Hopwood, 1966. The effect of a single subcutaneous injection of estradiol-17beta-monopalmitate on growth in turkeys. Poultry Sci. 45:829-833. Osborn, W. E., R. E. Moreng and T. E. Hartung, 1969. Turkey lipid characteristics: influence of sex, age and estradiol-17 beta-monopalmitate. Poultry Sci. 48: 274-283. Pickett, L. D., B. F . Miller and R. E. Moreng, 1968.
493
494
R. C. BAKER AND D. V. VADEHRA
layer. MATERIALS AND METHODS
Twenty-five one day old eggs from each of ten different strains of chickens were used in this study. The eggs were stored at 13°C. before using. The study was carried out in May of 1968 and repeated in July of the same year. Of the ten strains five strains (heavies) laid brown eggs and five strains (White Leghorns) laid white eggs. U.S.D.A. scores were determined by one person while Haugh units were measured by another. The percent thick albumen was determined as follows: The shelled eggs were weighed in grams and then broken out. The weight of the shell, membranes, and the residual albumen was deducted from the weight of the shelled egg. The yolks (including the chalaziferous layer and chalazae) were separated and the albumen was placed on a 16 mm. mesh screen over a beaker. The thick albumen
(middle thick) was cut several times with a knife to allow the inner thin white to drain. The outer and inner thin albumen passed through the screen and the percent thick albumen was determined by dividing the weight of the thick albumen by the weight of the total internal egg contents including the yolk. One minute was allowed for the thin albumen to pass through the screen, and this was found adequate for complete separation. Percent thick albumen in this study is not the same as reported by Lorenz et al. (1931), Wesley and Stadelman (1959) and Skala and Swanson (1962a) since they determined the percent thick white based only on total albumen. RESULTS AND DISCUSSION
The data on the egg quality measurements is summarized in Table 1. Analysis of variance was used to test significance on values obtained for three internal quality factors. The percent thick albumen was highly significantly different (P < .01) among the strains. This agrees with Lorenz et al. (1931) who found that the amount of thick albumen was an inherited factor. The eggs from the heavy breeds did not differ significantly from the Leghorns TABLE 1.—Average values for egg quality measurements for ten strains of chickens1 E ^S color
A B C D E F G H I J 1
White White White White White Brown Brown Brown Brown Brown
a ll b^u e m
n U.S.D.A. ^' scores percent
Haugh units
36.80 cd 2 3 . 9 4 ^ 7 5 . 5 2 ^ 39.78 a 3.66 ab 7'7.74abc 39.1(U 3.46 a 79.02 a 3S.96Cde 4.06 cd 74.56 bcd 34.02 e 3.66 ab 77.98 ab 37.86 abcd 4 . 0 4 ^ 74.52 cd 35.90^ 4.16 d 73.64 d 38.18ab« 4.00 bcd 74.64 bcd 38.19ab= 3.70 abo 77.82 abo 37.24bcd 4.02 bod 7 4 . 7 0 ^
Each figure average of SO eggs. Means followed by the same letter subscript are not significantly different from each other (5% level). 2
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
not as good an indicator of internal quality as some other measurements. The eggs used for their work apparently were all from one strain of chickens. Skala and Swanson (1962a) studied the variation in initial quality of eggs. They selected hens within a strain that laid high quality eggs and compared them to hens in the same strain that laid poor quality eggs. They found that the higher quality eggs were heavier and contained a larger amount of total white than did the lower quality eggs. They also found that the total white of the high quality eggs contained a significantly higher percentage of thick white and a lower percentage of weight of outer thin white than did the lower quality eggs. Skala and Swanson (1962b) in a continuing study found the whole whites and the middle thick and inner thin white layers from the higher quality eggs contained higher concentrations of total solids and total nitrogen, but this was not true of the outer thin
495
THICK ALBUMEN AND EGG QUALITY
TABLE 2.—Ranking of egg quality measurements for ten strains E
Strain
?g color
A B C D E F G H I
White White White White White Brown Brown Brown Brown Brown
J
Thick albumen' .' percent 7 1 2 8 10 5 9 4 3 6
* i =: best, 10 = poorest.
5 3 1 9 2 8 10 6 4 7
5 4 1 8 2 9 10 7 3 6
TABLE 3.—Correlation coefficient values of percent thick albumen and internal quality measurements
Strain Egg color
Correlation coefficients between percent thick albumen and U.S.D.A. scores Haugh units
A B C D E F G H I
J
White White White White White Brown Brown Brown Brown Brown
—0.573 -0.361 -0.373 -0.552 -0.423 -0.370 -0.601 -0.653 -0.600 -0.546
+0.695 +0.453 +0.477 +0.563 +0.386 +0.333 +0.521 +0.665 +0.650 +0.682
of thick albumen and yet had internal egg quality measurements which ranked second. Apparently, in Strain E the thick albumen is so placed that it gives the appearance of good quality eggs. Correlation coefficients were run on percent thick albumen and U.S.D.A. scores and also on percent thick albumen and Haugh units (Table 3). All of the correlation coefficients were highly significant but not high enough to conclude that the amount of thick white had an appreciable effect upon U.S.D.A. scores or Haugh units. Even with the higher correlation coefficients, only approximately 40 percent of internal egg quality measurements could be accounted for by the amount of thick albumen. In some of the strains as low as ten percent of the internal quality determination could be accounted for by the percent of firm albumen. Some other factor or factors must influence the internal egg quality determinations. It would appear that the shape of the firm albumen envelope (upstanding or flattened) when the egg is broken-out is more important than the actual amount. I t is also possible that the relative position of the yolk (centered or not centered) may influence the height of the thick albumen and thus affect the measurement. The average of the "r" values for per-
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
which seems to disagree with the findings of Knox et al. (1931) who found that White Leghorns as a breed had more thick albumen in their eggs than Rhode Island Reds. U.S.D.A. scores were significantly (P < .01) different for the various strains and also for Leghorns as compared to heavies. The U.S.D.A. scores were superior for the strains that laid white eggs. This is somewhat surprising since the percent thick albumen did not differ significantly. This would indicate that this scoring system was not totally dependent on percent thick albumen. Haugh units also differed significantly (P<.01) among the strains and between Leghorns and heavies. In this study, with all three internal quality measurements, the replications were not significantly different nor were treatments times replications. Duncan's new multiple range test was used to determine significances among the means (Table 1). The averages of the figures for the three egg quality measurements were ranked for comparison and the results are shown in Table 2. In most cases there was a fair agreement between percent thick albumen and internal egg quality scores. There was one major exception in Strain E, however, in that these eggs had the lowest percent
496
R. C. BAKER AND D. V. VADEHRA
SUMMARY
Percent thick albumen was highly significantly different (P<.01) among the strains but not different between Leghorns and heavy breeds. U.S.D.A. scores and Haugh units
showed highly significant differences (P <.01) among the strains and between Leghorns and heavy breeds. Correlation coefficients for percent thick albumen and U.S.D.A. scores were low as was the case for percent thick albumen and Haugh units. Position of the thick albumen relative to the yolk is undoubtedly more important than the actual amount in determining internal quality by the use of U.S.D.A. scores or Haugh units. REFERENCES Knox, C. W., and A. B. Godfrey, 1931. Variability of thick albumen in fresh-laid eggs. Poultry Sci. 13: 18-24. Lorenz, F. W., L. W. Taylor and H. J. Almquist, 1931. Firmness of albumen as an inherited characteristic. Poultry Sci. 13: 14-17. Sauter, E. A., J. V. Harns and W. J. Stadelman, 1953. Relationship of candled quality of eggs to other quality measurements. Poultry Sci. 32: 850-854. Skala, J. H., and M. H. Swanson, 1962a. Studies of variation in initial quality of chicken eggs. 1. Physical measurements of albumen and yolks. Poultry Sci. 41: 1533-1536. Skala, J. H., and M. H. Swanson, 1962b. Studies of variation in initial quality of chicken eggs. 2. Chemical properties of the albumen. Poultry Sci. 41: 1537-1545. Wesley, R. L., and W. J. Stadelman, 1959. Measurements of interior quality. Poultry Sci. 38: 474481.
NEWS AND NOTES {Continued from page 458) 1. Stick closely to the time allotted if you don't want the chairman to cut you off. Rehearse your speech. Take whatever steps you must to provide a margin of 1-2 minutes. This fosters your popularity and intelligent discussion from the floor. 2. If possible, do not read your manuscript. Know your material, and make it sound extemporaneous. 3. Do not show more than 3 slides in 5 minutes of speaking time. Slides must be intelligible, even to those who cannot hear what you are saying. They must be properly marked, not overcrowded, and of
course, legible. Don't show photographs of tables taken from published papers. They are seldom clear enough, and usually contain more than can be absorbed during a speech. If abbreviations must be used, explain them. 4. When showing slides, talk to the audience not the screen. If the slides need comment, have a copy in front of you. Use a pointer only a minimum. Remember, you are not transparent. 5. Time is precious. Some formalities may be omitted or pared ruthlessly: (a) all but the briefest historical introduction; (b) bibliographical refer-
{Continued on page 522)
Downloaded from http://ps.oxfordjournals.org/ at UPVA on June 16, 2015
cent firm albumen and U.S.D.A. scores was higher for the heavies ( — 0.554) than for the Leghorns ( — 0.456). This is not great but certainly worth noting. The average of the "r" values for percent thick albumen when related to Haugh units was also greater for the heavies (+.570) than for the Leghorns (+0.515). It is generally agreed among people who candle eggs that there isn't always a good agreement between the candling score of eggs and the internal quality measurements such as U.S D.A. scores and Haugh units. This is supported by Sauter et al. (1953). Eggs from certain strains of chickens will look better when candled than their actual "break out" appearance or vice versa. The results of this study can offer an explanation for this since percent thick white is far from being the sole factor influencing internal egg quality measurements and the quantity of firm albumen should influence candling.