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The Use of Egg Weight and Chick Weight Coefficients of Variation as Quality Indicators in Hatchery Management1
01993 Applied Poultty Science, I n c
THEUSE OF EGGWEIGHT AND CHICK WEIGHT COEFFICIENTS OF VARIATION AS QUALITY INDICATORS IN HATCHERY MANAGEMENT^
Primary Audience: Hatchery Managers, Breeder Production Managers, Researchers
of variation (C.V.), has been suggested as a DESCRIPTION OF PROBLEM potential indicator of this type. The C.V is
The ultimate measure of quality control in hatcheries is the number of top quality chicks obtained from the eggs set. However, hatchery managers need additional indicators of hatchery and breeder performance that will assist them in determining the probable causes of reduced hatchability and chick quality. The variation in chick weight in comparison to setting egg weight, as measured by the coefficient 1 2
defrned as the average deviation of the individual weights from the overall mean and is ex-
pressed as a percent of the overall mean. Numerous studies have investigated the relationship between the weight of the eggs at the beginning of incubationto the weight of the newly hatched chick. These have been reviewed by Shanawany [l],Wilson [2, 31, and others. However, little information has been
Florida Agricultural Experiment Station Journal Series No. R-03101 To whom correspondence should be addressed
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
H. R.WILSON2 and M. E. SUAREZ Poultry Science Department, University of Florida, P.O. Box 110930, Gainesville, FL 32611-0930 Phone: (904) 392-1931 FAX: (904) 392-3047
HATCHERY QUALITY INDICATOR
228
in the back. Eggs and chicks were weighed individually at setting, transfer (21 days), and at hatching (24 days). Eggs from White Leghorns (HyLine W-36)were used in Experiment 4. Four hundred eggs, stored 1-3 days, were weighed individually at setting and at hatching (21 days). The eggs were incubated under normal incubation conditions. The results were summarized by egg-weight groupings as well as for the overall or combined average.
RESULTS AND DISCUSSION Average initial egg weights for bobwhite eggs in Experiment 1 were 11.04 g for the Flight Strain and 11.96 g for the Meat Strain with corresponding chick weights of 6.88 and 7.36 g (Table 1). CY’S increased significantly (PS.OS) from 4.23% for egg weight to 9.24% for chick weight in the Flight Strain. C.V.’s in the Meat Strain increased similarly from 3.90% for egg weight to 9.65% for chick weight. There was a significant strain effect on C.X’s of chicWegg weight. In Experiment 2 the setting weight and transfer weight of hatched eggs were very uniform; therefore, the C.V.’s for egg weight and transfer weight were small (Table 2). However, the low air movement groups, by chance, each contained one unusually large egg which, due to the small number of eggs set, resulted in larger C.V.’s for all eggs set. Because these
MATERIALS AND METHODS Three experiments were conducted with bobwhite quail eggs and one with White Leghorn eggs. In Experiment 1,sixty eggs from the University of Florida Flight Strain of bobwhite and forty eggs from the University of Florida Meat Strain of bobwhite were weighed individually at setting, incubated in a Robbins IH-A incubator (100.5”Fand 86°F wet bulb), and weighed individually when removed from the hatcher at 24 days of incubation. Bobwhite eggs used in Experiments2 and 3 were from the Flight Strain used in Experiment 1.The eggs were subjected to the following four air movement treatments: low during both incubation (0-21 days) and hatching, low during incubation and high during hatching, high during incubation and low during hatching, high during both incubation and hatching. Low air movement was measured as 83 (60130) feet per minute (FPM) in the front of the incubator and 85 FPM (55-120) in the back. High air movement was measured as 182FPM (125-275) in the front and 232 FPM (120420)
TRAIT
FLIGHT STRAINA
MEAT STRAINB
Setting eggwt (g)
11.04
11.96
Settingwt C.V. (%)
4.23b
3.90b
Chickwt f!z\
6.88
7.36
*N =
(io
BN = 40 *bC.V.meansforsettingweight andchickweightwithin a strain having no common superscript are significantly different (P < .OS). There was no significant difference between strains. Significantly different (P < .OS) between strains.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
presented concerningeither the expected C.V. of eggs at setting or chicks at hatching, or on factors which influence the C.V. The C.V. of egg weights from 26-week-old hens calculated from the data of Petersen [4] was lower than that of egg weights of 55-week-old hens (4.93 vs. 6.83%). Genotype, nutrition, and numerous other factors may affect egg weight C.V. Chick weight is affected by egg weight and thus by the many factors affecting egg weight. Chick weight is additionally affected by weight loss during incubation, shell and residue weights, and dehydration due to the length of time between hatching and removal of the chick from the hatcher [q.Therefore, these sources of variation might suggest a higher C.V. for chick weight than for egg weight. This hypothesis is confirmed in C.V.’s calculated from the data of Petersen [4], in which C.Vs for egg and chick weight were 4.93 and 5.49% at 26 weeks and 6.83 and 8.22% at 55 weeks of breeder age. Chick weight C.V.’s calculated from the data of Shanawany [6] were lower and showed that age had no major effect (4.43% at 28 weeks and 3.23% at 44weeks). The objective of these studies was to determine the level of variation, expressed as C.V., for egg weight at setting, egg weight at transfer (two experiments), and chick weight.
Research Report 229
WILSON and SUAREZ
TABLE 2. Coefficients of variation (C.V.) for egg weight at setting, egg weight at transfer, chick weight, and chick weight as a percent of egg weight in bobwhite quail (Experiment 2)
large eggs subsequently failed to hatch, the C.V.’sfor setting weight of hatched eggs, transfer eggs, and chicks were reduced and comparable to those of the high air movement groups. This result suggests that the setting of extreme sized eggs can be reflected in abnormal C.V.’s. The C.V.’s of chick weight were significantly larger than those at set or transfer, a frndingwhich indicated that factors other than initial egg weight also have major effects on chick weight. The variation in chick weight
expressed as a percent of set egg weight was very similar to that of chick weight and was affected by air movement treatment. In Experiment 3 the egg weight at setting was more variable than in Experiment 2 as indicated by the range of C.V.’s of eggs set: from 5.09 to 6.62% (Table 3). The C.V.’s of chick weights were higher than for eggs at setting or transfer, ranging from 8.18 to 10.17%. However, these differences were not significant ( P I .05). Air movement treatments
TABLE 3. Coefficients of variation (C.V.) for egg weight at setting, egg weight at transfer, chick weight, and chick weight as a percent of egg weight in bobwhite quail (Experiment 3)A
N
I
38
35
22
I
27
*C.V.’s did not differ significantly (PS.05) among air movement treatments or among egg and chick weights.
BAir movement codes are LOW = 83-85 FPM and HIGH = 182-232 FPM.Before slash (0 is in incubator; after slash is in hatcher.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
ight C.V.’swithin a column having no common superscript are significantly different (PS.05).
JAPR HATCHERY QUALITY INDICATOR
230
TABLE 4. Coefficients of variation (C.V.) for egg weight and chick weight in White Leghorn chickens (Experiment 4)*
56.0-58.9
48.68
71.0-73.9
Total All eggs set
1
I
282 400
I
73.80
-
58.96 58.96
the calculate’d value (chick weight as a percent of set weight) was similar in magnitude to that of chick weight. In Experiment 3 it was more similar to that of set weight. Therefore, in the quail it is normal for the variation in weight to increase from the time the eggs are set until the chicks are hatched. As expected, factors other than initial egg weight also have major effects on variation (expressed as C.V.) during incubation. In these studies, neither strain nor air movement had major influences on the variation of transfer egg weights or chick weights. The results of Experiment 4 with eggs from White Leghorn chickens confirm those found with the bobwhite quail. The C.V. for overall chick weight was significantly greater than that for egg weight at setting (Table 4).
I
5.68
-
6.76
52.90 41.06
8.47
6.97
-
-
Experiment 3. Grouping by egg weight at setting increased the difference between egg weight and chick weight C.V.’s although the magnitude of both C.V.’s was less. It is apparent from these studies that if the comparison of the C.V. of the chick weight at hatching with that of eggs at setting is used to evaluate the quality of hatchery performance, then the chick weight C.V. should be expected to be higher. The use of C.V.’s as a criterion of hatchery performance will require the development of a large body of baseline data in the scientific literature and by the user hatchery. Additional information will also be necessary on the effects of numerous factors on C.V.’s utilized and on the interpretation of changes in the C.V.’s.
CONCLUSIONS AND APPLICATIONS 1. The use of variation comparisons, expressed as C.V.’s, between the egg weight at setting and chick weight has merit as a potential quality control indicator. 2. The C.V. of chick weight will normally be higher than that of egg weight at setting or egg weight at transfer to the hatcher. 3. Egg weight has a known major effect on chick weight and its C.V.; however, a number of other factors may also have major influences. The magnitude of these effects needs to be determined. 4. In order for the C.V.3 of egg weight, transfer weight, and chick weight to be used effectively by commercial hatcheries for quality control, it will be necessary to develop appropriate baseline data for each hatchery and for the effect of factors such as age, strain, season, nutrition, microenvironment, and disease.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
68.0-70.9
Research Report WILSON and SUAREZ
231
REFERENCES AND NOTES
P
1. Shanmany, M.M., 1987.Hatching wei t in relation to egg weight in domestic birds. World’s oultry Sci.
J. 43:107-115.
2.W b n , H.R, 1991. Effects of egg sue on hatchability, chick size and posthatchin v h . Pages 279-283 In: “Avian Incubation,” Poultly kience Symposium No. 22; Ed. S.G. Tullett, Buttenvorth-Heineman Ltd.,Surrey,
UK. 3. Wilson, H.R, 1991. Interrelationships of e size, chick size,posthatching growth and hatchability. #orld’s PoultIy Sci. J. 475-20.
4. Petersen, C.B., 1984.Egg weight and weight of day old chicks the influence on growth rate and feed efficiency of broilers. National Committee for Poultry and Eggs, Denmark, pp. 1-44.
-
5. Tullett, S.G. and F.C. Burton, 1982.Factors affecting the weight and water status of the chick at hatch. Br. Poultry Sci. 25361-369. 6. S h a m a n y , M.M., 1984. Inter-relationship between egg weight, arental age and embryonic develop25:449455. ment. Br. Poultry
&.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
THEUSE OF EGGWEIGHT AND CHICK WEIGHT COEFFICIENTS OF VARIATION AS QUALITY INDICATORS IN HATCHERY MANAGEMENT^
Primary Audience: Hatchery Managers, Breeder Production Managers, Researchers
of variation (C.V.), has been suggested as a DESCRIPTION OF PROBLEM potential indicator of this type. The C.V is
The ultimate measure of quality control in hatcheries is the number of top quality chicks obtained from the eggs set. However, hatchery managers need additional indicators of hatchery and breeder performance that will assist them in determining the probable causes of reduced hatchability and chick quality. The variation in chick weight in comparison to setting egg weight, as measured by the coefficient 1 2
defrned as the average deviation of the individual weights from the overall mean and is ex-
pressed as a percent of the overall mean. Numerous studies have investigated the relationship between the weight of the eggs at the beginning of incubationto the weight of the newly hatched chick. These have been reviewed by Shanawany [l],Wilson [2, 31, and others. However, little information has been
Florida Agricultural Experiment Station Journal Series No. R-03101 To whom correspondence should be addressed
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
H. R.WILSON2 and M. E. SUAREZ Poultry Science Department, University of Florida, P.O. Box 110930, Gainesville, FL 32611-0930 Phone: (904) 392-1931 FAX: (904) 392-3047
HATCHERY QUALITY INDICATOR
228
in the back. Eggs and chicks were weighed individually at setting, transfer (21 days), and at hatching (24 days). Eggs from White Leghorns (HyLine W-36)were used in Experiment 4. Four hundred eggs, stored 1-3 days, were weighed individually at setting and at hatching (21 days). The eggs were incubated under normal incubation conditions. The results were summarized by egg-weight groupings as well as for the overall or combined average.
RESULTS AND DISCUSSION Average initial egg weights for bobwhite eggs in Experiment 1 were 11.04 g for the Flight Strain and 11.96 g for the Meat Strain with corresponding chick weights of 6.88 and 7.36 g (Table 1). CY’S increased significantly (PS.OS) from 4.23% for egg weight to 9.24% for chick weight in the Flight Strain. C.V.’s in the Meat Strain increased similarly from 3.90% for egg weight to 9.65% for chick weight. There was a significant strain effect on C.X’s of chicWegg weight. In Experiment 2 the setting weight and transfer weight of hatched eggs were very uniform; therefore, the C.V.’s for egg weight and transfer weight were small (Table 2). However, the low air movement groups, by chance, each contained one unusually large egg which, due to the small number of eggs set, resulted in larger C.V.’s for all eggs set. Because these
MATERIALS AND METHODS Three experiments were conducted with bobwhite quail eggs and one with White Leghorn eggs. In Experiment 1,sixty eggs from the University of Florida Flight Strain of bobwhite and forty eggs from the University of Florida Meat Strain of bobwhite were weighed individually at setting, incubated in a Robbins IH-A incubator (100.5”Fand 86°F wet bulb), and weighed individually when removed from the hatcher at 24 days of incubation. Bobwhite eggs used in Experiments2 and 3 were from the Flight Strain used in Experiment 1.The eggs were subjected to the following four air movement treatments: low during both incubation (0-21 days) and hatching, low during incubation and high during hatching, high during incubation and low during hatching, high during both incubation and hatching. Low air movement was measured as 83 (60130) feet per minute (FPM) in the front of the incubator and 85 FPM (55-120) in the back. High air movement was measured as 182FPM (125-275) in the front and 232 FPM (120420)
TRAIT
FLIGHT STRAINA
MEAT STRAINB
Setting eggwt (g)
11.04
11.96
Settingwt C.V. (%)
4.23b
3.90b
Chickwt f!z\
6.88
7.36
*N =
(io
BN = 40 *bC.V.meansforsettingweight andchickweightwithin a strain having no common superscript are significantly different (P < .OS). There was no significant difference between strains. Significantly different (P < .OS) between strains.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
presented concerningeither the expected C.V. of eggs at setting or chicks at hatching, or on factors which influence the C.V. The C.V. of egg weights from 26-week-old hens calculated from the data of Petersen [4] was lower than that of egg weights of 55-week-old hens (4.93 vs. 6.83%). Genotype, nutrition, and numerous other factors may affect egg weight C.V. Chick weight is affected by egg weight and thus by the many factors affecting egg weight. Chick weight is additionally affected by weight loss during incubation, shell and residue weights, and dehydration due to the length of time between hatching and removal of the chick from the hatcher [q.Therefore, these sources of variation might suggest a higher C.V. for chick weight than for egg weight. This hypothesis is confirmed in C.V.’s calculated from the data of Petersen [4], in which C.Vs for egg and chick weight were 4.93 and 5.49% at 26 weeks and 6.83 and 8.22% at 55 weeks of breeder age. Chick weight C.V.’s calculated from the data of Shanawany [6] were lower and showed that age had no major effect (4.43% at 28 weeks and 3.23% at 44weeks). The objective of these studies was to determine the level of variation, expressed as C.V., for egg weight at setting, egg weight at transfer (two experiments), and chick weight.
Research Report 229
WILSON and SUAREZ
TABLE 2. Coefficients of variation (C.V.) for egg weight at setting, egg weight at transfer, chick weight, and chick weight as a percent of egg weight in bobwhite quail (Experiment 2)
large eggs subsequently failed to hatch, the C.V.’sfor setting weight of hatched eggs, transfer eggs, and chicks were reduced and comparable to those of the high air movement groups. This result suggests that the setting of extreme sized eggs can be reflected in abnormal C.V.’s. The C.V.’s of chick weight were significantly larger than those at set or transfer, a frndingwhich indicated that factors other than initial egg weight also have major effects on chick weight. The variation in chick weight
expressed as a percent of set egg weight was very similar to that of chick weight and was affected by air movement treatment. In Experiment 3 the egg weight at setting was more variable than in Experiment 2 as indicated by the range of C.V.’s of eggs set: from 5.09 to 6.62% (Table 3). The C.V.’s of chick weights were higher than for eggs at setting or transfer, ranging from 8.18 to 10.17%. However, these differences were not significant ( P I .05). Air movement treatments
TABLE 3. Coefficients of variation (C.V.) for egg weight at setting, egg weight at transfer, chick weight, and chick weight as a percent of egg weight in bobwhite quail (Experiment 3)A
N
I
38
35
22
I
27
*C.V.’s did not differ significantly (PS.05) among air movement treatments or among egg and chick weights.
BAir movement codes are LOW = 83-85 FPM and HIGH = 182-232 FPM.Before slash (0 is in incubator; after slash is in hatcher.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
ight C.V.’swithin a column having no common superscript are significantly different (PS.05).
JAPR HATCHERY QUALITY INDICATOR
230
TABLE 4. Coefficients of variation (C.V.) for egg weight and chick weight in White Leghorn chickens (Experiment 4)*
56.0-58.9
48.68
71.0-73.9
Total All eggs set
1
I
282 400
I
73.80
-
58.96 58.96
the calculate’d value (chick weight as a percent of set weight) was similar in magnitude to that of chick weight. In Experiment 3 it was more similar to that of set weight. Therefore, in the quail it is normal for the variation in weight to increase from the time the eggs are set until the chicks are hatched. As expected, factors other than initial egg weight also have major effects on variation (expressed as C.V.) during incubation. In these studies, neither strain nor air movement had major influences on the variation of transfer egg weights or chick weights. The results of Experiment 4 with eggs from White Leghorn chickens confirm those found with the bobwhite quail. The C.V. for overall chick weight was significantly greater than that for egg weight at setting (Table 4).
I
5.68
-
6.76
52.90 41.06
8.47
6.97
-
-
Experiment 3. Grouping by egg weight at setting increased the difference between egg weight and chick weight C.V.’s although the magnitude of both C.V.’s was less. It is apparent from these studies that if the comparison of the C.V. of the chick weight at hatching with that of eggs at setting is used to evaluate the quality of hatchery performance, then the chick weight C.V. should be expected to be higher. The use of C.V.’s as a criterion of hatchery performance will require the development of a large body of baseline data in the scientific literature and by the user hatchery. Additional information will also be necessary on the effects of numerous factors on C.V.’s utilized and on the interpretation of changes in the C.V.’s.
CONCLUSIONS AND APPLICATIONS 1. The use of variation comparisons, expressed as C.V.’s, between the egg weight at setting and chick weight has merit as a potential quality control indicator. 2. The C.V. of chick weight will normally be higher than that of egg weight at setting or egg weight at transfer to the hatcher. 3. Egg weight has a known major effect on chick weight and its C.V.; however, a number of other factors may also have major influences. The magnitude of these effects needs to be determined. 4. In order for the C.V.3 of egg weight, transfer weight, and chick weight to be used effectively by commercial hatcheries for quality control, it will be necessary to develop appropriate baseline data for each hatchery and for the effect of factors such as age, strain, season, nutrition, microenvironment, and disease.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015
68.0-70.9
Research Report WILSON and SUAREZ
231
REFERENCES AND NOTES
P
1. Shanmany, M.M., 1987.Hatching wei t in relation to egg weight in domestic birds. World’s oultry Sci.
J. 43:107-115.
2.W b n , H.R, 1991. Effects of egg sue on hatchability, chick size and posthatchin v h . Pages 279-283 In: “Avian Incubation,” Poultly kience Symposium No. 22; Ed. S.G. Tullett, Buttenvorth-Heineman Ltd.,Surrey,
UK. 3. Wilson, H.R, 1991. Interrelationships of e size, chick size,posthatching growth and hatchability. #orld’s PoultIy Sci. J. 475-20.
4. Petersen, C.B., 1984.Egg weight and weight of day old chicks the influence on growth rate and feed efficiency of broilers. National Committee for Poultry and Eggs, Denmark, pp. 1-44.
-
5. Tullett, S.G. and F.C. Burton, 1982.Factors affecting the weight and water status of the chick at hatch. Br. Poultry Sci. 25361-369. 6. S h a m a n y , M.M., 1984. Inter-relationship between egg weight, arental age and embryonic develop25:449455. ment. Br. Poultry
&.
Downloaded from http://japr.oxfordjournals.org/ at New York University on June 10, 2015