scholarly journals CORRELATED RESPONSES IN WEIGHTS OF IMPROVED INDIGENOUS PIGS - NIGERHYB - IN NIGERIA

2021 ◽  
Vol 22 (2) ◽  
pp. 113-119
Author(s):  
O. A. Adebambo
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Genetic Correlations ◽  
Correlated Responses ◽  
Good Criterion ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Indigenous Pigs

Data collected on the weight of 1681 offsprings of improved indigenous pigs from 1984 to 1990 were used to obtain heritability estimates; genetic, environmental and phenotypic correlations among weights and gains from birth to mature and yearling weights. The estimates were used to predict expected change from correlated responses from single trait selection. Heritability estimates obtained from paternal half-sib analysis were birth weight 0.90 ±0. 08; gain from birth to weaning 0.14±0.11; 150 days weight 0.49±18; gain from weaning to 150 days 0.49±0.15; weight gain from.150 days to yearling weight 0.41 ± 026 and yearling weight 0.66±. Genetic correlations among all weights and gains were fairly high, ranging from 0.25 to 0.81. Selection for individual pig weight at 56 days appear to be a single good criterion for selection for growth at other ages with coheritabilities of 0.669 for 56 and 150 days weight and 0,856 for 56 days versus yearling weight.

The role of selection in the improvement of Welsh Mountain sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 819 ◽  
Author(s):  
JM Doney
Keyword(s):  
Birth Weight ◽  
Maternal Environment ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Fleece Weight ◽  
Staple Length

Means and variances of several economic characters in Welsh Mountain sheep are given. The repeatabilities of, and phenotypic correlations between, these characters are generally within the range of similar estimates given for other breeds. Heritabilities, calculated from parent-offspring correlations, were : birth weight 0.39, weaning weight 0.68, 18-month weight 0.59, greasy fleece weight 0.61, and staple length 0.73. These values are in general higher than similarly derived estimates from other breeds. A method of correcting heritability estimates to remove the error due to correlation between maternal environment, and the character as measured in the dam, is described. This reduces the estimate for weaning weight to 0.48, and that for 18-month weight to 0.16, but does not change that for fleece weight. The use of such estimates in predicting the effect of selection is discussed, and it is concluded that accurate selection for the chosen economic characters will result in improvement at the present genetic stage of the breed.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

Genetic and phenotypic relationships between fertility and wool production in 2-year-old Merino sheep

1967 ◽  
Vol 18 (3) ◽  
pp. 515 ◽  
Author(s):  
JP Kennedy
Keyword(s):  
Body Weight ◽  
Genetic Correlations ◽  
Standard Errors ◽  
Phenotypic Correlation ◽  
Correlated Responses ◽  
Merino Sheep ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Fertility Traits

Records of the lambing and weaning performance (fertility) of 2-year-old Peppin Merino ewes were analysed. Repeatability and heritability of number of lambs born and weaned were low. Heritability of number of lambs born was significantly different from zero (0.20 ± 0.10). Phenotypic and genetic correlations between the fertility traits and greasy wool weight, all measured at approximately 15 months of age, were calculated. Phenotypic correlations between number of lambs born or weaned and greasy wool weight were negative and significant. The phenotypic correlation between number of lambs weaned and clean wool weight was negative and significant. Significant negative genetic correlations were found between number of lambs born and both greasy wool weight and clean wool weight. Genetic correlations between number of lambs weaned and the fleece and body traits had very large standard errors. The results were used to estimate correlated responses in fertility resulting from selection for greasy wool weight, clean wool weight, and body weight of –0.08i, –0.13i, and 0.03i respectively.

RESPONSE TO SELECTION FOR WEIGHT-PER-DAY-OF-AGE IN RAMBOUILLET AND ROMNELET SHEEP

1975 ◽  
Vol 55 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J. A. VESELY ◽  
H. F. PETERS
Keyword(s):  
Genetic Correlations ◽  
Response To Selection ◽  
Correlated Responses ◽  
Weaning Weight ◽  
Two Generations ◽  
Selection For ◽  
Heritability Estimates

Responses to selection for weight-per-day-of-age (WPDA) to about 170 days in Rambouillet and Romnelet sheep over 5 yr, comprising two generations, were measured by two methods. Correlated responses in weaning weight (WW) at about 100 days, and postweaning gain (PWG) for 70 days were also estimated. The estimates of annual genetic increases in WPDA were quite similar in both breeds and from both methods. The improvements of this trait in Rambouillet and Romnelet were estimated as 9.7 and 6.0 g/yr from method 1, and 9.1 and 7.8 g/yr from method II. Estimates of correlated responses in PWG obtained by both methods and in both breeds were close to expected estimates, but correlated responses in WW appeared to be overestimated. Heritability estimates for WPDA using paternal half-sibs were 0.20 for Rambouillet and 0.18 for Romnelet. All genetic correlations among the three traits were positive. Realized heritabilities for WPDA were 0.28 and 0.20 in Rambouillet and Romnelet by method I, and 0.26 in both breeds by method II.

Estimates of genetic and phenotypic parameters for growth traits of D'Man lambs

1990 ◽  
Vol 51 (1) ◽  
pp. 173-178 ◽  
Author(s):  
I. Boujenane ◽  
M. Kerfal
Keyword(s):  
High Weight ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Phenotypic Correlations ◽  
High Magnitude ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates

ABSTRACTThe heritability of growth traits from birth to 6 months of age and the genetic and phenotypic correlations among them were determined from paternal half-sib analyses of 1689 records of D'man lambs. Heritability estimates were 0·34 (s.e. 0·08), 0·23 (s.e. 0·06), 0·52 (s.e. 0·10) and 0·43 (s.e. 0·09) for weights at birth, 30 days, 90 days and 180 days, respectively. Heritabilities for average daily gains from birth to 30 days and from 30 to 90 days were estimated to be 0·12 (s.e. 0·05) and 0·56 (s.e. 0·11), respectively. Genetic and phenotypic correlations among growth traits were all positive and of high magnitude. The former estimates varied from 0·66 to 0·98, the latter estimates ranged from 0·23 to 0·92. Selection for high weight at 90 days would be expected to have large effect on other growth traits as a result of their large positive genetic correlations.

Genetic and phenotypic parameters of some measures of lifetime production and their relationship with milk yield in the first three lactations in Tharparkar cows

1982 ◽  
Vol 98 (2) ◽  
pp. 461-465
Author(s):  
V. K. Taneja ◽  
S. B. Basu ◽  
D. S. Bhatnagar
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Traits ◽  
Correlated Responses ◽  
The Third ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

SUMMARYThe genetic parameters of lifetime production traits and their relationship with milk yield in first, second and third lactations were estimated from information on 753 Tharparkar cows. The heritability estimates for milk yield in first, second and third lactations were 0·22 ± 0·10, 0·33 ± 0·14 and 0·49 ± 0·17 and for number of lactations completed, lifetime milk production, number of days in milk and herd life 0·58 ± 0·23, 0·51 ± 0·22, 0·54 ± 0·22 and 0·34 ± 0·20 respectively. The genetic and phenotypic correlations among the four lifetime production traits were in the range of 0·83–1·0 and 0·84–0·85 respectively. The phenotypic correlations of milk yield in first, second and third lactations with lifetime production traits were significant and ranged between 0·15 and 0·56. The corresponding genetic correlations ranged between 0·26 and 0·83. For the first three lactations, the genetic correlations of lifetime traits with the third lactation were high and that between lifetime milk yield and yield in third lactation the highest (0·83 ± 0·17). The direct and correlated responses from single trait selection were also estimated.

scholarly journals Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Parameter Estimates ◽  
Sampling Variance ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

Genetic parameter estimates (full sib and half sib analysis) of fertility and hatchability in two strains of Rhode Island chickens

2021 ◽  
Vol 38 (1) ◽  
pp. 14-22
Author(s):  
M. Orunmuyi ◽  
I. A. Adeyinka ◽  
O.O Oni
Keyword(s):  
Rhode Island ◽  
Additive Genetic Variance ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Parameter Estimates ◽  
Phenotypic Correlations ◽  
Poultry Breeding ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

A study was conducted to estimate the genetic parameters of fertility and hatchability in two strains of Rhode Island Red (RIR) Chickens denoted as Strain A and Strain B respectively using the full-sib (sire +dam variance) and maternal half-sib (dam variance) components. The birds were obtained from the selected populations of RIR Chickens kept at the poultry breeding programme of National Animal Production Research Institute, Shika, Zaria, Nigeria. Settable eggs were collected from mating 28 cocks to 252 hens in a ratio of 1cock:9 hens from each strain. Eggs were pedigreed according to sire and dam. Results showed that values obtained for number of egg set (EGGSET), number of fertile eggs (NFERT), number of hatched chicks (NHATCH), percentage of chicks hatched from total eggs set (PHATCH) and percentage of chicks hatched from fertile eggs (PHATCHBL) were all higher in strain A than strain B. Heritability estimates obtained from the full-sib and maternal half-sib analysis ranged from medium to high for the two strains (0.24-0.96). The maternal half sib estimates were higher (0.40-0.96) than the estimates obtained from full sibs (0.24- 0.48). Genetic and phenotypic correlations obtained for both strains were positive and similar regardless of method of estimation. Genetic correlations between EGGSET and PFERT were low in strain A using both full-sib and maternal half-sib analyses (0.09-0.14). Phenotypic correlations between EGGSET and PFERT, PHATCH and PHATCHBL were also low in both strains and regardless of method of analyses. Moderate to high heritability estimates suggest that genetic improvement can be obtained by selection of these reproductive traits. The full-sib analysis for estimating heritability will be preferred since it is assumed that only additive genetic variance contributes to the covariance between family members.

Estimates of genetic and phenotypic parameters of some weight and fleece traits in a coarse-wool breed of sheep

1982 ◽  
Vol 99 (2) ◽  
pp. 277-285 ◽  
Author(s):  
R. A. Guirgis ◽  
E. A. Afifi ◽  
E. S. E. Galal
Keyword(s):  
Body Weight ◽  
Genetic Correlations ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
Heritability Estimates ◽  
Fleece Weight ◽  
Staple Length

SUMMARYA study using 1150 lambs to estimate genetic and phenotypic parameters of some weight and fleece traits was carried out on coarse-wool Barki sheep. The weight traits were birth, weaning, yearling weights and daily gains whereas fleece traits included kemp score, staple length and greasy-fleece weight.Heritability estimates of weight traits were within the range 0·25–0·30. Those of fleece traits were 0·16, 0·21 and 0·43. The repeatability estimates of fleece traits were 0·18, 0·38 and 0·53 for staple length, greasy-fleece weight and kemp score respectively.Phenotypic correlations between body weight and fleece traits were mostly positive. Genetic correlations between greasy-fleece weight and body weights were mostly positive and of medium values. Those between kemp score and body weights were mostly negative, ranging from medium-high to high.

Response to selection in Australian Merino sheep. III. Single character selection for high and low values of wool weight and its components

1970 ◽  
Vol 21 (6) ◽  
pp. 955 ◽  
Author(s):  
HN Turner ◽  
MG Brooker ◽  
CHS Dolling
Keyword(s):  
Body Weight ◽  
Unit Area ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Initial Response ◽  
Skin Area ◽  
Correlated Responses ◽  
Fibre Number ◽  
Selection For ◽  
Staple Length

Direct and correlated responses are reported for 10 traits in eight pairs of lines under selection for high and low values of single characteristics : clean wool weight per head, clean wool weight per unit skin area (measured only in the groups under selection for it), body weight, wrinkle score, fibre number per unit skin area (adjusted for body weight), fibre diameter, staple length, and percentage clean yield. All groups showed overall divergence in the character under selection, though response was not always symmetrical, and in two cases (long staple and low fibre number) there was no continuing response after the initial response to extreme selection of the base parents. In all except one case, whenever previous estimates of genetic correlation were at the level of 0.2 or higher, correlated responses were in the predicted direction, though not always symmetrical in magnitude. The exception was a previously reported negative correlation between fibre number and staple length, which was not exhibited under selection for either character. Where two characters of a pair were under selection, reciprocal responses agreed in sign; magnitude will be examined in a later paper. Wool per unit area was shown to have a greater influence on clean wool weight than that of surface area, with staple length on this occasion being the most important component of wool per unit area. Reasons for an apparent decrease in the relative importance of fibre number are discussed. Three other points of importance in sheep breeding are again emphasized by these results : 1. Crimp in several pairs of groups was a poor indicator of fibre diameter. 2. Increases in clean wool weight were associated with falls in crimp number, even though fibre diameter actually became finer; diameter, not crimp, should therefore be used as a guide to wool quality. 3. The absence of genetic correlations DL and NL indicates that selection can be for high N (fibre number) with high L (staple length) and low D (fibre diameter) -in other words, a desirable fleece -with no impeding genetic correlations.

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