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Inheritance of Viability of Pullets in the Laying House1
Inheritance of Viability of Pullets in the Laying House 1 F. A. HAYS University of Massachusetts, Amherst (Received for publication January 11, 1954)
H
1107
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Breeding practices in a closed flock in IGH viability of pullets in the laying house is one of the most important which high fecundity is the major objecqualifications of a superior flock. For a tive do include high viability, but it would considerable period of time, attention of be safe to say that in many cases high promany workers has been directed toward ducing individuals are selected for breedthe value of selective breeding as a tool ing from low viability families. In modern to increase viability. Recently Moultrie, terminology, selection pressure for high King and Cottier (1953) have reported viability may be inadequate to maintain very significant progress in reducing mor- high viability in the flock because of low tality through selective breeding. Many heritability of viability. other workers have made valuable conLush, Lamoreux and Hazel (1948) retributions. Their work is cited by the Ala- port an extensive study on the heritability bama workers and need not be reviewed of viability in White Leghorns. In a threehere. Most pedigree breeders now include year period they found the heritability to viability in their selection program. be 8.3 percent. Robertson and Lerner Since selective breeding has been effec- (1949) made estimates on the heritability tive in reducing mortality, it seems very of total mortality, and arrived at a value probable that hereditary factors may be in of 8.93 percent, which is very close to the operation. Due consideration should be value given by Lush et al. (1949). These given, however, to such important en- studies indicate that viability has a very vironmental factors as exposure to and low degree of heritability. contraction of diseases and parasites, proData Available on Rhode Island Reds. tective vaccinations, medicinal treat- Mortality records are available for famiments, nutrition, housing, and general lies of sisters for 365 days in the laying management, all of which may affect the houses over the ten-year period from 1942 death rate. to 1951. All pullets were bred for high Breeding for High Fecundity and Via- fecundity in a closed flock. Mean mortalbility. Most of the recent reports indicated ity for the period was 23.38 percent, and that egg production may increase in lines no culling was practiced. Yearly mortality bred for high viability as a major objec- fluctuated widely with no consistent tive, but for the most part such lines have trend. not attained the high level of egg producThe binomial a(t—a)/t suggested by tion that exists in superior flocks. All data Lush et al. (1948) was used in all calculaon the Massachusetts Agricultural Ex- tions. It was possible to find some eviperiment Station flock of Rhode Island dence of heritability in our data only by Reds seem to indicate that fecundity and using four years in which the mean morviability are independent entities. tality rate for the year was very similar. After much preliminary calculation, it was 1 Contribution No. 939 from the Massachusetts decided to use the data on birds hatched in 1942, 1947, 1948, and 1950. The morAgricultural Experiment Station.
1108
W. W. SADLER, H. S. WILGUS AND E. G. BUSS
tality rates for these years were 22.12, 26.17, 21.13, and 25.24 percent respectively. It was also necessary to omit all 0 mortality families and to include only families with ten or more sisters housed. The data are summarized in tabular form. Variance in laying house mortality— Rhode Island Reds Source Total Between Sires Between Dams Between Full Sisters 0288
ss
Mean sq.
Components of mean square
1,170 42 48
215.64 9.86 9.53
.2348 .1985
B+dA+sS B+dA
1,080
196.25
.1817
B
5 (i =
B+A+S
These data substantiate previous observations that heritability of viability in the laying house is extremely low. Our
REFERENCES Lush, J. L., W. F. Lamoreux and L. N. Hazel, 1948. The heritability of resistance to death in the fowl. Poultry Sci. 27: 375-388. Moultrie, F., D. F. King and C. J. Cottier, 1953. Fifteen years of selection for viability in White Leghorns. Poultry Sci. 32:454-461. Robertson, A., and I. M. Lemer, 1949. The heritability of all-or-none traits: viability of poultry. Genetics, 34:395-411.
Incubation Factors Affecting Hatchability of Poultry Eggs 2. SOME EFFECTS OF CARBON DIOXIDE UPON MORPHOGENESIS 12 W. W. SADLER3, H. S. WILGUS 4 AND E. G. BUSS Poultry Section, Colorado Agricultural Experiment Station, Fort Collins, Colorado (Received for publication August 4, 1953)
T
HE reports of Ells and Morris (1947), Meshew (1949), Stephenson (1950), and Wilgus and Sadler (1954), indicated that ventilation in itself is not adequate under certain conditions to supply the proper amounts of oxygen and carbon dioxide during incubation. Furthermore, Meshew (1949) and Wilgus and 1
Colorado Agricultural Experiment Station Scientific Paper No. 343. 2 This investigation was supported in part by a grant from the International Baby Chick Association (American Poultry Hatchery Federation). 3 Now at the University of California School of Veterinary Medicine. 4 Resigned.
Sadler (1954) presented evidence of an interrelationship between CO2 and O2 in their effect on embryonic development. Evidence for this was given earlier by Romanoff (1930) and Romanoff and Romanoff (1933), although the data were complicated by the fact that O2 was not maintained at a constant level as CO2 was increased. Barott (1938) concluded that hatchability decreased as CO2 concentration was increased above 0.5 percent, the lowest level used. The most fundamental approach to this problem was that of Romijn and Roos (1938). Levels of 0 2 and C0 2 available to the embryo in the air cell of
Downloaded from http://ps.oxfordjournals.org/ by guest on May 19, 2015
(' = .0072
d/f
data indicate a heritability of 2.88 percent in Rhode Island Reds. On the whole, it appears that viability as measured by deaths in families of full sisters during the first laying year is highly variable and subject to a vast array of factors. Extreme selection pressure is now being applied to viability in this flock, and future developments will be watched with interest.
H
1107
Downloaded from http://ps.oxfordjournals.org/ by guest on May 19, 2015
Breeding practices in a closed flock in IGH viability of pullets in the laying house is one of the most important which high fecundity is the major objecqualifications of a superior flock. For a tive do include high viability, but it would considerable period of time, attention of be safe to say that in many cases high promany workers has been directed toward ducing individuals are selected for breedthe value of selective breeding as a tool ing from low viability families. In modern to increase viability. Recently Moultrie, terminology, selection pressure for high King and Cottier (1953) have reported viability may be inadequate to maintain very significant progress in reducing mor- high viability in the flock because of low tality through selective breeding. Many heritability of viability. other workers have made valuable conLush, Lamoreux and Hazel (1948) retributions. Their work is cited by the Ala- port an extensive study on the heritability bama workers and need not be reviewed of viability in White Leghorns. In a threehere. Most pedigree breeders now include year period they found the heritability to viability in their selection program. be 8.3 percent. Robertson and Lerner Since selective breeding has been effec- (1949) made estimates on the heritability tive in reducing mortality, it seems very of total mortality, and arrived at a value probable that hereditary factors may be in of 8.93 percent, which is very close to the operation. Due consideration should be value given by Lush et al. (1949). These given, however, to such important en- studies indicate that viability has a very vironmental factors as exposure to and low degree of heritability. contraction of diseases and parasites, proData Available on Rhode Island Reds. tective vaccinations, medicinal treat- Mortality records are available for famiments, nutrition, housing, and general lies of sisters for 365 days in the laying management, all of which may affect the houses over the ten-year period from 1942 death rate. to 1951. All pullets were bred for high Breeding for High Fecundity and Via- fecundity in a closed flock. Mean mortalbility. Most of the recent reports indicated ity for the period was 23.38 percent, and that egg production may increase in lines no culling was practiced. Yearly mortality bred for high viability as a major objec- fluctuated widely with no consistent tive, but for the most part such lines have trend. not attained the high level of egg producThe binomial a(t—a)/t suggested by tion that exists in superior flocks. All data Lush et al. (1948) was used in all calculaon the Massachusetts Agricultural Ex- tions. It was possible to find some eviperiment Station flock of Rhode Island dence of heritability in our data only by Reds seem to indicate that fecundity and using four years in which the mean morviability are independent entities. tality rate for the year was very similar. After much preliminary calculation, it was 1 Contribution No. 939 from the Massachusetts decided to use the data on birds hatched in 1942, 1947, 1948, and 1950. The morAgricultural Experiment Station.
1108
W. W. SADLER, H. S. WILGUS AND E. G. BUSS
tality rates for these years were 22.12, 26.17, 21.13, and 25.24 percent respectively. It was also necessary to omit all 0 mortality families and to include only families with ten or more sisters housed. The data are summarized in tabular form. Variance in laying house mortality— Rhode Island Reds Source Total Between Sires Between Dams Between Full Sisters 0288
ss
Mean sq.
Components of mean square
1,170 42 48
215.64 9.86 9.53
.2348 .1985
B+dA+sS B+dA
1,080
196.25
.1817
B
5 (i =
B+A+S
These data substantiate previous observations that heritability of viability in the laying house is extremely low. Our
REFERENCES Lush, J. L., W. F. Lamoreux and L. N. Hazel, 1948. The heritability of resistance to death in the fowl. Poultry Sci. 27: 375-388. Moultrie, F., D. F. King and C. J. Cottier, 1953. Fifteen years of selection for viability in White Leghorns. Poultry Sci. 32:454-461. Robertson, A., and I. M. Lemer, 1949. The heritability of all-or-none traits: viability of poultry. Genetics, 34:395-411.
Incubation Factors Affecting Hatchability of Poultry Eggs 2. SOME EFFECTS OF CARBON DIOXIDE UPON MORPHOGENESIS 12 W. W. SADLER3, H. S. WILGUS 4 AND E. G. BUSS Poultry Section, Colorado Agricultural Experiment Station, Fort Collins, Colorado (Received for publication August 4, 1953)
T
HE reports of Ells and Morris (1947), Meshew (1949), Stephenson (1950), and Wilgus and Sadler (1954), indicated that ventilation in itself is not adequate under certain conditions to supply the proper amounts of oxygen and carbon dioxide during incubation. Furthermore, Meshew (1949) and Wilgus and 1
Colorado Agricultural Experiment Station Scientific Paper No. 343. 2 This investigation was supported in part by a grant from the International Baby Chick Association (American Poultry Hatchery Federation). 3 Now at the University of California School of Veterinary Medicine. 4 Resigned.
Sadler (1954) presented evidence of an interrelationship between CO2 and O2 in their effect on embryonic development. Evidence for this was given earlier by Romanoff (1930) and Romanoff and Romanoff (1933), although the data were complicated by the fact that O2 was not maintained at a constant level as CO2 was increased. Barott (1938) concluded that hatchability decreased as CO2 concentration was increased above 0.5 percent, the lowest level used. The most fundamental approach to this problem was that of Romijn and Roos (1938). Levels of 0 2 and C0 2 available to the embryo in the air cell of
Downloaded from http://ps.oxfordjournals.org/ by guest on May 19, 2015
(' = .0072
d/f
data indicate a heritability of 2.88 percent in Rhode Island Reds. On the whole, it appears that viability as measured by deaths in families of full sisters during the first laying year is highly variable and subject to a vast array of factors. Extreme selection pressure is now being applied to viability in this flock, and future developments will be watched with interest.