Heritability Estimates and Genetic Correlations Among Several Traits in a Meat-Type Poultry Population ,

Kinney, T. B.; Shoffner, Robert N.

doi:10.3382/ps.0441020

Cited by 26 publications

(11 citation statements)

References 19 publications

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“…Genetically, these two traits were found to have a highly significant negative relationship with each other. These results are in accord with the findings of other workers (King, 1961;Husain and Singh, 1964^;Kinney and Shoffner, 1965;Kinney et al, 1968) who also reported age at sexual maturity and egg production to be negatively associated. Some of the reported correlations are larger than unity.…”

Section: Resultssupporting

confidence: 95%

“…Estimates of genetic correlation between age at sexual maturity and annual egg production have been reported to have a wide range. Except for Bray et al (i960) and Krueger et al (1952), who reported a low and positive correlation, most of the estimates reported in literature are negative (King, 1961;Kinney and Shoffner, 1965;Kinney et al, 1968). Very few estimates of these parameters have been reported for Indian flocks of White Leghorns (Husain and Singh, 1964a, b;Tandon, Rao and Lachiramani, 1968).…”

Section: Introductionmentioning

confidence: 71%

“…In general, age at sexual maturity has been reported to have a medium heritability, ranging from 0.07 (Krueger,Dickerson,175 I76 R. M. ACHARYA, J. S. DHILLON AND M. S. TIWANA Kinder and Kempster, 1952) to 0*57 (King, 1961) with an unweighted average of 0-34 (Kinney, Lowe, Boheren and Wilson, 1968). Egg production on the other hand has been reported to have a low heritability ranging from o (Wyatt, 1954) to o-6i (Bray,King and Anderson,i960) and an unweighted average of 0*16 (Kinney and Shoffner, 1965). Estimates of genetic correlation between age at sexual maturity and annual egg production have been reported to have a wide range.…”

Section: Introductionmentioning

confidence: 95%

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Age at first egg and egg production — their inheritance and expected response to different methods of selection

Acharya

Dhillon

Tiwana

1969

British Poultry Science

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SYNOPSISData pertaining to a closed White Leghorn flock maintained at the Punjab Agricultural University were used for estimating genetic and phenotypic parameters for age at first egg and 70-d egg production and also to evaluate the expected response to different methods of selection. Records of 2377 pullets, a progeny of 1001 dams and 155 sires over a period of two years, were used. The birds in this flock attained sexual maturity on an average at the age of 176.6 d and produced on an average 33.6 eggs in first 70 d of egg production.Heritability for age at first egg and 70-d egg production was obtained from different observational components. Age at first egg was found to have a medium heritability, the estimates being 0.370 ±0.003, 0.080 ±0.016 and 0.224 + 0.040 from sire, dam and full sib components, respectively. The heritabilities for 70-d egg production were low. The estimates were 0.132±0.004, 0.214±0.011 and 0.173±0.06 from sire, dam and full sib components, respectively. Phenotypic, genetic and environmental correlations were also obtained from analysis of variance and covariance. These two traits were found to be highly genetically negatively associated (-0.554 ±0.007). Phenotypic and environmental correlations between these two traits were also found to be negative and very low.An index incorporating age at first egg and 70-d egg production with 1.5 times negative weightage to the former was found to be two times more effective in reducing the age at first egg and 2-3 times more effective in increasing the 70-d egg production as compared to direct selection for the two traits individually.

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Section: Resultssupporting

confidence: 95%

Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 95%

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Age at first egg and egg production — their inheritance and expected response to different methods of selection

Acharya

Dhillon

Tiwana

1969

British Poultry Science

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“…The positive genetic correlation between juvenile body weight and percentage HDP of normal eggs, while in contrast with the consistantly negative relationship reported by others (Dillard et at., 1953;McClung, 1958;Merritt and Gowe, 1962;King et al, 1963, Siegel, 1963Kinney and Shoffner, 1965;Ideta and Siegel, 1966;van Middelkoop, 1973), is consistent with some estimates. For example, Krueger et al (1952) and Hale (1961) obtained values of 0.13 and 0.12 between juvenile body weight and normal eggs, respectively, and Jaap et al (1962) obtained a positive genetic correlation between 8-week body weight and percentage production of normal eggs.…”

Section: Heritability Estimatessupporting

confidence: 82%

“…Ideta and Siegel (1966) reported evidence of a correlation between genotypes and environments in the earlier generations of selection. Although negative genetic correlations between age at maturity and rate of egg production have been reported on several occasions (King, 1961;Hale, 1961;Kinney and Shoffner, 1965;Kinney and Low, 1968;Merritt, 1968), positive correlations are infrequent. While these data suggest an effect of the feeding program on this correlation they do not provide information on the optimum level of energy restriction to maximize normal egg production via delayed sexual maturity.…”

Section: Heritability Estimatesmentioning

confidence: 90%

Selection for Body Weight at Eight Weeks of Age

Siegel

1977

Poultry Science

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Correlated responses in egg production patterns were studied in lines of White Plymouth Rocks selected bidirectionally for juvenile body weight and in their respective relaxed lines. The production traits measured were the numbers and percentage hen-day production of normal, double-yolked, broken, ovulatory defective, and total defective eggs and yolks. Increasing the photoperiod beyond 14 hours in a 24-hour period from 119 days of age did not have a consistent effect on either body weight or reproductive traits. The frequency of various defective egg-types was significantly higher in the high weight than in the low weight lines. Relaxing selection for high body weight resulted in fewer double yolked and the total number of defective eggs, while relaxing selection for low body weight has no influence on any of the abnormal egg-types.The average heritability estimates for percentage hen-day production of normal eggs and yolks were similar. Heritability estimates of the total defective eggs were moderate to high and the genetic correlations among traits were generally larger than the phenotypic correlations.

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Selection for egg production on part records

Ayyagari

Mohapatra

Venkatramaiah

et al. 1980

Theoret. Appl. Genetics

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Responses from four generations of index selection for egg production to 280 days of age in four White Leghorn populations have been presented. A pedigreed randombred population derived from one of the lines was reared with the selected lines to measure the environmental trend. The magnitude of total as well as average response although varying from population to population was positive in all the lines studied. Close correspondence between predicted and realized gains indicated that natural selection, genotype environmental interactions and environmental fluctuations were unimportant during the course of selection. Realized heritabilities agreed fairly well with the estimated heritabilities in at least three out of four populations studied. Probable reasons for variable and insufficient response were investigated.

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Heritability Estimates and Genetic Correlations Among Several Traits in a Meat-Type Poultry Population ,

Cited by 26 publications

References 19 publications

Age at first egg and egg production — their inheritance and expected response to different methods of selection

Age at first egg and egg production — their inheritance and expected response to different methods of selection

Selection for Body Weight at Eight Weeks of Age

Selection for egg production on part records

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