Estimating the association between wool and skin characters and fleece rot

1983 ◽  
Vol 34 (1) ◽  
pp. 47 ◽  
Author(s):  
R Evans ◽  
BJ McGuirk
Keyword(s):  
Correlation Coefficient ◽  
Selection Criteria ◽  
Genetic Correlations ◽  
Indirect Selection ◽  
Phenotypic Correlation ◽  
Phenotypic Correlations ◽  
Standard Deviations

To assess the value of skin and fleece characters as potential indirect selection criteria for increased resistance to fleece rot, estimates of the genetic correlations between the skin and fleece characters and fleece rot are needed. The characters most likely to be useful can be identified relatively cheaply and quickly by estimating the phenotypic correlation with fleece rot. This paper illustrates how phenotypic correlations with fleece rot, scored as an all-or-none character, can be estimated retrospectively from published estimates of means and standard deviations of fleece and skin characters measured in groups of sheep affected by or free from fleece rot. The paper emphasizes the incidence-dependent nature of the correlation coefficient so obtained, and points out that this must be allowed for when comparisons of correlations are made between flocks in which the incidence of fleece rot differs. This problem can be avoided by using the concept of liability to fleece rot. Data from three recently published papers are used to illustrate the main points.

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.

scholarly journals Estimation of genetic parameters and relationships between type traits and milk yield of Holstein cows in Turkey

2021 ◽  
Vol 73 (6) ◽  
pp. 1371-1380
Author(s):  
O. Ermetin ◽  
B. Dağ
Keyword(s):  
Milk Yield ◽  
Selection Criteria ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Scoring Systems ◽  
Holstein Cows ◽  
Phenotypic Correlations ◽  
Type Traits ◽  
Final Score ◽  
Selection For

ABSTRACT In this study, milk yield, reproductive yield, and type traits of 533 Holstein cows in the first lactation raised in 54 farms were examined. In the three-year study, phenotypic (rP) and genetic (rG) correlations between type traits and milk yield were estimated based on the variance elements and heritability of the type traits of Holstein cows in the first lactation. Linear identification and scoring systems have been applied to classify the cows according to type traits. Heritability and correlations were estimated with ASREML models. The type traits included stature, angularity, rump width, hocks, rear udder height, central ligament, teat length, body capacity, feet and legs, udder composite and final score for genetic correlations with 305-day milk yield were estimated as -0.49, -0.14, -0.93, 0.35, 0.40, 0.11, -0.65, 0.70, 0.31, 0.54, and 0.70, for phenotypic correlations were estimated as 0.28, 0.28, 0.30, 0.21, 0.35, 0.39, -0.06, 0.46, 0.48, 0.56, and 0.58 respectively. Among the phenotypic correlations between the type traits, especially the phenotypic correlations between the final score and various type traits were found to be high and significant. The fact that these traits are in high correlation with other traits and milk yield may enable these to be used as indirect selection criteria in the selection for milk yield.

HERITABILITY OF TEAT NUMBER IN SWINE

1990 ◽  
Vol 70 (2) ◽  
pp. 425-430 ◽  
Author(s):  
R. M. McKAY ◽  
G. W. RAHNEFELD
Keyword(s):  
Key Words ◽  
Genetic Correlation ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Data Set ◽  
Phenotypic Correlations ◽  
Teat Number ◽  
Genetic And Phenotypic Correlations ◽  
Time Periods ◽  
Selection For

Heritabilities were estimated for teat number in nine populations of swine over two time periods. From 1962 to 1974 the populations included Lacombe, Yorkshire, and Lacombe × Yorkshire. In this data set, only total teat number was recorded. From 1982 to 1988 three purebred populations (Landrace, Yorkshire, and Hampshire) and three crossbred populations (Landrace-Yorkshire rotation, Landrace × Yorkshire, and Landrace × Hampshire) were represented and total teat number and the number of teats anterior and posterior to the navel were recorded. Heritabilities for total teat number were greater in the 1982–1988 data (ranging from 0.27 to 0.47) than in the 1962–1974 data (ranging from 0.20 to 0.32). The heritability of posterior teat numbers (ranging from 0.08 to 0.39) was generally larger than the heritability of anterior teat numbers (ranging from 0.03 to 0.21) and both were considerably less than the heritability of total teat number. Genetic and phenotypic correlations were calculated for the relationships between anterior and posterior teat numbers (AP), anterior and total teat numbers (AT), and posterior and total teat numbers (PT). The relative magnitudes of the genetic and phenotypic correlations with respect to AP, AT, and PT revealed that selection for increased total teat number would increase the number of anterior and posterior teats. However, the larger genetic correlations for PT relative to AT would lead to a greater increase in posterior teat number than anterior teat number. Key words: Pigs, teat number, heritability, genetic correlation, phenotypic correlation

A preliminary genetic analysis of breech and tail traits with the aim of improving the welfare of sheep

2007 ◽  
Vol 58 (2) ◽  
pp. 161 ◽  
Author(s):  
D. R. Scobie ◽  
D. O'Connell ◽  
C. A. Morris ◽  
S. M. Hickey
Keyword(s):  
New Zealand ◽  
Genetic Analysis ◽  
Genetic Correlation ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Linear Scale ◽  
Bare Area ◽  
Phenotypic Correlations ◽  
Tail Docking

The area of naturally bare skin around the perineum was scored at weaning in lambs (n = 2152) from a composite flock of New Zealand crossbred sheep. Breech bareness was scored on a range from 1, where wool was growing right to the edges of the anus, to 5, where a large bare area surrounded the perineum. Bareness on the under surface of the tail was measured on a linear scale at tail docking. Dag score (degree of breech soiling) was recorded at weaning, on a scale of 0–5, where an increasing score indicated more dags. Dag score was taken as a measure of the risk of flystrike in the breech. Female lambs tended to have slightly greater (P < 0.001) breech bareness score (mean score 2.7) than males (mean score 2.6), whereas mean dag score of females was lower than that of males (0.45 v. 0.53; P < 0.05). Breech bareness score had a heritability of 0.33 ± 0.06, and the length of bare skin under the tail had a heritability of 0.59 ± 0.06. The genetic correlation between breech bareness score at weaning and length of bare skin under the tail at docking was positive (0.35 ± 0.10). These 2 traits had phenotypic correlations with dag score of –0.17 ± 0.02 and –0.03 ± 0.03, respectively, and genetic correlations with dag score of –0.30 ± 0.13 and 0.03 ± 0.12, respectively; negative values indicated a favourable relationship. Tails were removed at docking, so the phenotypic correlation of about zero between tail data and dag score at weaning was of little utility. Our results suggest that selecting for these 2 bareness traits could reduce dag formation and the associated risk of breech strike.

Evaluation of repeatability and pre-structured repeatability models for genetic analyses of repeated records of fat and protein contents of milk in Iranian Holstein cows

2018 ◽  
Vol 58 (11) ◽  
pp. 1983
Author(s):  
M. Asadi Fozi
Keyword(s):  
Genetic Analysis ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Holstein Cows ◽  
Phenotypic Correlation ◽  
Genetic Covariance ◽  
Future Studies ◽  
Phenotypic Correlations ◽  
Variance Structure

Fat and protein content of milk measurements from first to fifth lactations of Iranian Holstein cows were analysed using repeatability and several pre-structured repeatability models that varied in additive genetic variance structure and fitted heterogeneous residual co (variance). For this research, a total of 257 197 fat and 218 688 protein records were used. The records were measured on 116 531 cows born between 2010 and 2014. The animals originated from 2355 sires and 91 212 dams. Pre-structured repeatability models with heterogeneous residual co (variance) and the respective genetic variance structure were the best models for genetic analysis of the fat and protein data. The results derived from these models showed that heritability of both fat and protein are decreased from first to fifth lactations. Heritability of fat measured at first, second, third, fourth and fifth locations were between 0.10 and 0.19 and those for protein were between 0.07 and 0.24. Moderate to high phenotypic correlations were estimated between the repeated records of the fat and protein. Values of 0.13 and 0.16 were estimated for heritability of fat and protein using repeatability model. Phenotypic correlations among the repeated records of fat and protein were estimated to be 0.30 and 0.33, respectively when this model was applied. The results showed the genetic variance, heritability and phenotypic correlation of the fat and protein are changed over the lactations but the genetic parameters derived from the repeatability model are homogenous whereas in both models unity genetic correlations are assumed among the repeated records. The results of this study show that the repeatability model is not an appropriate model for genetic analysis of the repeated records of fat and protein in the population investigated and can be improved when pre-structured repeatability model is used. In the present study homogenous genetic covariance was assumed among the fat and protein taken at the different lactations which can be modelled in future studies for more improving the models.

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.

scholarly journals Genotypic and Phenotypic Correlations between Leaf-Rust Disease and Leaf Morphology and its Ratio in Arabica Coffee

2020 ◽  
Vol 25 (3) ◽  
pp. 468-477
Author(s):  
Sabam Malau
Keyword(s):  
Leaf Rust ◽  
Leaf Area ◽  
Selection Criteria ◽  
Leaf Morphology ◽  
Indirect Selection ◽  
Leaf Length ◽  
Rust Disease ◽  
Phenotypic Correlations ◽  
Genotypic And Phenotypic Correlations ◽  
Rust Severity

  Selection parameter in coffee breeding for leaf rust (Hemeleia vastatrix) resistance is very important. Breeders used leaf-rust severity and leaf-rust incidence as parameters of direct selection. However, scientific proof is not yet available whether leaf morphology can be used as a parameter of indirect selection. The objective of this research was to seek the possibility of leaf morphology parameter and its ratio to be used as selection criteria through analyses of genotypic and phenotypic correlations of parameter of rust disease and parameter of leaf morphology and its ratio. The result revealed that genotypes showed significant variations in leaf-rust severity (5.21–25.84%), leaf morphology, and leaf-morphology ratio. Leaf length to leaf width ratio, leaf length to leaf area ratio, and leaf width to leaf weight ratio were not affected by the environment. Leaf-rust severity performed highly significant positive genotypic and phenotypic correlations the ratio of with leaf length to leaf area. For selection criteria, leaf-rust severity could be better used rather than leaf-rust incidence and branch-rust incidence. The ratio of leaf length to leaf area could also be used as an indirect selection criterion because the ratio showed a highly significant genotypic correlation with leaf-rust severity (rGab = 0.254**). However, the ratio of leaf length to leaf area is even better chosen for selection criteria rather than leaf-rust severity because the ratio was not affected by the environment.   Keywords: fungus, Hemeleia vastatrix, indirect selection

scholarly journals GENETIC AND PHENOTYPIC CORRELATIONS FOR BODY WEIGHTS IN YANKASA SHEEP

2021 ◽  
Vol 18 ◽  
pp. 12-18
Author(s):  
W. A. HASSAN ◽  
N. I. DIM ◽  
O. A. OSINOWO ◽  
B. Y. ABUBAKAR
Keyword(s):  
Genetic Correlation ◽  
Correlation Coefficient ◽  
Correlation Coefficients ◽  
Phenotypic Correlation ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations ◽  
One Year

Using paternal half-sib (PHS) analysis, coefficients of genetic and phenotypic correlations be- tween body weights of Yankasa lambs at birth, weaning (three months), six months, nine months and one year of age were estimate. The highest genetic correlation coefficient of 0.33 was obtained between birth and yearling weight. Six- month weight had very low and negative genetic correlation with yearling weight (-0.04). Phenotypic correlation coefficients for the various body weights pairs were positive and mostly of medium magnitude (0.12 -0.47). 

INHERITANCE OF FLOWERING TIME AND ITS APPLICATION FOR INDIRECT SELECTION IN THE DAVIS POPULATION OF GERBERA

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1357F-1358
Author(s):  
Yiran Yu ◽  
James Harding ◽  
Thomas Byrne
Keyword(s):  
Flowering Time ◽  
Genetic Correlations ◽  
Indirect Selection ◽  
Cut Flower ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Components Of Variance ◽  
Genetic Components ◽  
Flower Yield ◽  
Cut Flower Yield

Genetic components of variance and heritability of flowering time were estimated for five generations of the Davis Populationof Gerbera hybrids, Composite, Estimates of narrow-sense heritability averaged 0.50 and broad-sense heritability averaged 0.77 using the NCII design. Narrow-sense heritability was also estimated with two models of parent-offspring regression, resulting in average heritability of 0.49 and 0.51. Estimates of components of variance indicated that the major genetic effect controlling flowering time is additive. However, the dominance component accounted for 28% of the total variance; the environmental component was only 23%. Flowering time is negatively correlated with cut-flower yield. The phenotypic coefficient was –0.34; genetic correlations were –0.47 when estimated from the NCII design, and –0.72 when estimated from the parent-off-spring method. A practical model was constructed to assess the efficiency of indirect selection for cut-flower yield using flowering time as a marker trait. The advantages of indirect selection accruing from increased population size and reduced generation time are discussed.

scholarly journals Genetic Influences on the Covariance and Genetic Correlations in a Bivariate Twin Model: An Application to Well-Being

2021 ◽  
Author(s):  
Lianne P. de Vries ◽  
Toos C. E. M. van Beijsterveldt ◽  
Hermine Maes ◽  
Lucía Colodro-Conde ◽  
Meike Bartels
Keyword(s):  
Complex Traits ◽  
Educational Achievement ◽  
Genetic Correlations ◽  
Well Being ◽  
Genetic Influences ◽  
Phenotypic Correlation ◽  
Twin Model ◽  
Twin Models ◽  
Adolescent Twins ◽  
Depressed Symptoms

AbstractThe distinction between genetic influences on the covariance (or bivariate heritability) and genetic correlations in bivariate twin models is often not well-understood or only one is reported while the results show distinctive information about the relation between traits. We applied bivariate twin models in a large sample of adolescent twins, to disentangle the association between well-being (WB) and four complex traits (optimism, anxious-depressed symptoms (AD), aggressive behaviour (AGG), and educational achievement (EA)). Optimism and AD showed respectively a strong positive and negative phenotypic correlation with WB, the negative correlation of WB and AGG is lower and the correlation with EA is nearly zero. All four traits showed a large genetic contribution to the covariance with well-being. The genetic correlations of well-being with optimism and AD are strong and smaller for AGG and EA. We used the results of the models to explain what information is retrieved based on the bivariate heritability versus the genetic correlations and the (clinical) implications.

Sign in / Sign up

Export Citation Format

Share Document