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Hatching Egg Storage and Post Embryonic Performance
HATCHING EGG STORAGE AND POST EMBRYONIC PERFORMANCE E. S. MERRITT Animal Research Institute, Canada Department of Agriculture, Central Experimental Farm, Ottawa, Ontario, Canada (Received for publication November 5, 1969)
Because of the normal increase in the size of eggs laid during the laying year any set of data available for studying storage effects would be expected to show a negative correlation between egg weight and storage time. Egg weight effects on post-embryonic performance have been well documented (Goodwin, 1961; and others) so the possibility exists that storage effects can be accounted for by differences in egg weight. The increase in egg weight is curvilinear over a full proContribution No. 361, Animal Research Institute.
duction year so that absolute differences in egg weight due to flock age could differ between studies. For example over a 21day period over 2 g. (Bohren el al., 1952) might be expected if the hatching egg flock were in the early part of its production cycle and less than 0.5 g. if in the latter part. So if it were assumed that storage effects were due to egg weight differences then the variation in egg weight differences due to parent flock age could be one reason for conflicting findings between studies on egg storage effects. This note is based on results of an analysis in which both the weight and the length of the pre-incubation storage time of hatching eggs were considered jointly. Four years' data were available for a strain (Fredericton Meat Control) different from the strain (Ottawa Meat Control) on which the study by Merritt (1964) was based. The F.M.C. strain was reproduced yearly in a single hatch scheduled for the same week, each year and from hatching eggs collected over a 21-day period. Each year's breeding population consisted of 80 to 99 sires and 240 to 300 dams chosen from about 2,000 progeny; so there were data on about 8,000 individuals for the analysis. All pullets were retained through a complete laying year of 420 days while the males, except for the breeders, were marketed at 140-days of age. Hatching eggs were weighed individually and at the time of transfer to the hatcher set under individual egg baskets for hatching. Routine hatching egg storage practices were followed with the cooler
316
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 22, 2015
The juvenile growth of chickens was shown by Becker (1960) to be adversely affected when the eggs from which they hatched were stored longer than two weeks prior to incubation. Merritt (1964) confirmed Becker's findings and reported similar hatching egg storage effects on adult weight, egg weight and juvenile and adult viability. On the other hand Proudfoot (1968) reported no hatching egg storage effects on a number of performance traits. Proudfoot's study was based on eggs from a S. C. White Leghorn strain as opposed to the cited studies which were on meattype strains. He suggested that strain differences could be one reason for the lack of agreement between his and other studies. This hypothesis may be tenable although Merritt (1964) found no evidence that storage effects were the result of a genotype-environment (storage length) interaction on an intra-strain basis.
317
RESEARCH NOTES TABLE 1.—Partial regression coefficients for performance traits on hatching egg storage length {days) with egg weight held constant Trait
Males
Chick wt. (g.) 0.032** + 0.004 42-day body wt. (g.) - 2 . 4 4 9 » * + 0.276 56-day body wt. (g.) - 3 . 2 1 6 * * + 0 . 4 I 6 140-day body wt. (g.) - 4 . 3 3 8 " + 1 . 6 9 1 280-day body wt. (g.) 420-day body wt. (g.) A.F.E. (days) H . H . Egg Prod. (No.)i Egg wt. (g.)
Females 0.046** + 0.00S - 1 . 4 7 7 * * + 0.223 - 1 . 9 7 2 * * + 0.317 - 2 . 4 7 4 " + 0.861 -1.928 +1.416 -2.443 +1.549 0.079 + 0 . 0 6 4 -0.229» +0.115 -0.038» ±0.015
1 5-day trap basis. * PS0.05. "PjSO.01.
because of its positive environmental correlation with egg production. ACKNOWLEDGMENT The data for this study were collected at the Fredericton Research Station, CD.A. The author would like to express his appreciation to R. J. Curtis and N. Wolff for their supervision of the experiment and the collection of the data. REFERENCES Becker, W. A., 1960. The storage of hatching eggs and the post-hatching body weight of chickens. Poultry Sci. 39: 588-590. Bohren, B. B., G. D. Rapp and R. B. Arvidson, 1952. Increase in pullet size as a factor in selection. Purdue Univ. Agr. Expt. Sta. Bui. 574. Goodwin, K., 1961. Effect of hatching egg size and chick size upon subsequent growth rate in chickens. Poultry Sci. 40: 1408. Merritt, E. S., 1964. Pre-incubation storage effects on subsequent performance of chickens. British Poultry Sci. 5: 67-73. Merritt, E. S., 1968. Genetic parameter estimates for growth and reproductive traits in a randombred control strain of meat-type fowl. Poultry Sci. 47: 190-199. Proudfoot, F. G., 1968. Hatching egg storage effects on hatchability and subsequent performance of the domestic fowl. Poultry Sci. 47:1497-1500.
JULY 15-17. CONVENTION, AMERICAN POULTRY AND HATCHERY FEDERATION, CHASE PARK PLAZA HOTEL, ST. LOUIS MISSOURI AUGUST 2-6. ANNUAL MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, PENNSYLVANIA STATE UNIVERSITY, UNIVERSITY PARK
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 22, 2015
temperature maintained at approximately 9.5°C. The data were analyzed by multiple regression with egg weight and storage length treated as independent variables and the performance trait under consideration as the dependent variable. The 4 years' data were combined in a joint analysis and years considered, for purpose of the analysis, as a fixed effect. The results (Table 1) indicate clearly that pre-incubation storage effects cannot be accounted for by egg weight differences. The performance traits affected and the magnitude and trend of the storage effects are in good agreement with those reported by Merritt (1964). The only differences between the results of the two studies are in the statistical significance for adult weights and H. H. egg production. The adult weight differences were found significant in the 1964 study whereas the egg production differences were not. The trends however in both studies are the same for both traits. Pre-incubation storage of hatching eggs must change in some manner the "adequacy" of the environment for the developing embryo. The interesting biological aspect of this phenomenon is that it is long-lived as evidenced by the effect on traits, such as egg production and egg weight, which are only expressed some months after hatching. Egg weight and egg production show a negative genetic but a positive environmental correlation (Merritt, 1968; and others) so some decrease in egg weight might be expected
Because of the normal increase in the size of eggs laid during the laying year any set of data available for studying storage effects would be expected to show a negative correlation between egg weight and storage time. Egg weight effects on post-embryonic performance have been well documented (Goodwin, 1961; and others) so the possibility exists that storage effects can be accounted for by differences in egg weight. The increase in egg weight is curvilinear over a full proContribution No. 361, Animal Research Institute.
duction year so that absolute differences in egg weight due to flock age could differ between studies. For example over a 21day period over 2 g. (Bohren el al., 1952) might be expected if the hatching egg flock were in the early part of its production cycle and less than 0.5 g. if in the latter part. So if it were assumed that storage effects were due to egg weight differences then the variation in egg weight differences due to parent flock age could be one reason for conflicting findings between studies on egg storage effects. This note is based on results of an analysis in which both the weight and the length of the pre-incubation storage time of hatching eggs were considered jointly. Four years' data were available for a strain (Fredericton Meat Control) different from the strain (Ottawa Meat Control) on which the study by Merritt (1964) was based. The F.M.C. strain was reproduced yearly in a single hatch scheduled for the same week, each year and from hatching eggs collected over a 21-day period. Each year's breeding population consisted of 80 to 99 sires and 240 to 300 dams chosen from about 2,000 progeny; so there were data on about 8,000 individuals for the analysis. All pullets were retained through a complete laying year of 420 days while the males, except for the breeders, were marketed at 140-days of age. Hatching eggs were weighed individually and at the time of transfer to the hatcher set under individual egg baskets for hatching. Routine hatching egg storage practices were followed with the cooler
316
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 22, 2015
The juvenile growth of chickens was shown by Becker (1960) to be adversely affected when the eggs from which they hatched were stored longer than two weeks prior to incubation. Merritt (1964) confirmed Becker's findings and reported similar hatching egg storage effects on adult weight, egg weight and juvenile and adult viability. On the other hand Proudfoot (1968) reported no hatching egg storage effects on a number of performance traits. Proudfoot's study was based on eggs from a S. C. White Leghorn strain as opposed to the cited studies which were on meattype strains. He suggested that strain differences could be one reason for the lack of agreement between his and other studies. This hypothesis may be tenable although Merritt (1964) found no evidence that storage effects were the result of a genotype-environment (storage length) interaction on an intra-strain basis.
317
RESEARCH NOTES TABLE 1.—Partial regression coefficients for performance traits on hatching egg storage length {days) with egg weight held constant Trait
Males
Chick wt. (g.) 0.032** + 0.004 42-day body wt. (g.) - 2 . 4 4 9 » * + 0.276 56-day body wt. (g.) - 3 . 2 1 6 * * + 0 . 4 I 6 140-day body wt. (g.) - 4 . 3 3 8 " + 1 . 6 9 1 280-day body wt. (g.) 420-day body wt. (g.) A.F.E. (days) H . H . Egg Prod. (No.)i Egg wt. (g.)
Females 0.046** + 0.00S - 1 . 4 7 7 * * + 0.223 - 1 . 9 7 2 * * + 0.317 - 2 . 4 7 4 " + 0.861 -1.928 +1.416 -2.443 +1.549 0.079 + 0 . 0 6 4 -0.229» +0.115 -0.038» ±0.015
1 5-day trap basis. * PS0.05. "PjSO.01.
because of its positive environmental correlation with egg production. ACKNOWLEDGMENT The data for this study were collected at the Fredericton Research Station, CD.A. The author would like to express his appreciation to R. J. Curtis and N. Wolff for their supervision of the experiment and the collection of the data. REFERENCES Becker, W. A., 1960. The storage of hatching eggs and the post-hatching body weight of chickens. Poultry Sci. 39: 588-590. Bohren, B. B., G. D. Rapp and R. B. Arvidson, 1952. Increase in pullet size as a factor in selection. Purdue Univ. Agr. Expt. Sta. Bui. 574. Goodwin, K., 1961. Effect of hatching egg size and chick size upon subsequent growth rate in chickens. Poultry Sci. 40: 1408. Merritt, E. S., 1964. Pre-incubation storage effects on subsequent performance of chickens. British Poultry Sci. 5: 67-73. Merritt, E. S., 1968. Genetic parameter estimates for growth and reproductive traits in a randombred control strain of meat-type fowl. Poultry Sci. 47: 190-199. Proudfoot, F. G., 1968. Hatching egg storage effects on hatchability and subsequent performance of the domestic fowl. Poultry Sci. 47:1497-1500.
JULY 15-17. CONVENTION, AMERICAN POULTRY AND HATCHERY FEDERATION, CHASE PARK PLAZA HOTEL, ST. LOUIS MISSOURI AUGUST 2-6. ANNUAL MEETING OF THE AMERICAN SOCIETY OF ANIMAL SCIENCE, PENNSYLVANIA STATE UNIVERSITY, UNIVERSITY PARK
Downloaded from http://ps.oxfordjournals.org/ at University of British Columbia on June 22, 2015
temperature maintained at approximately 9.5°C. The data were analyzed by multiple regression with egg weight and storage length treated as independent variables and the performance trait under consideration as the dependent variable. The 4 years' data were combined in a joint analysis and years considered, for purpose of the analysis, as a fixed effect. The results (Table 1) indicate clearly that pre-incubation storage effects cannot be accounted for by egg weight differences. The performance traits affected and the magnitude and trend of the storage effects are in good agreement with those reported by Merritt (1964). The only differences between the results of the two studies are in the statistical significance for adult weights and H. H. egg production. The adult weight differences were found significant in the 1964 study whereas the egg production differences were not. The trends however in both studies are the same for both traits. Pre-incubation storage of hatching eggs must change in some manner the "adequacy" of the environment for the developing embryo. The interesting biological aspect of this phenomenon is that it is long-lived as evidenced by the effect on traits, such as egg production and egg weight, which are only expressed some months after hatching. Egg weight and egg production show a negative genetic but a positive environmental correlation (Merritt, 1968; and others) so some decrease in egg weight might be expected