In silico investigation of the effect of nutrition on the estimates of genetic parameters for lambs infected with gastro-intestinal parasites

In recent years there has been an increased interest for breeding lambs resistant to gastrointestinal parasites due to the reduced efficacy of anthelminthics. Furthermore, protein supplementation alleviates the adverse effects of parasitism since more protein is available for the satisfaction of the competing body functions of growth and resistance to parasites. Therefore, differences in dietary protein might result in the expression of genotype x environment interaction. Additionally the estimates of genetic and phenotypic correlations obtained from populations kept under different nutritional conditions might differ with implications for the breeding programmes. The aim here is to explore the effect of dietary protein level on the estimates of genetic and phenotypic correlations of a population of growing lambs infected with gastrointestinal parasites using a simulation model.

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

Genetics ◽

10.1093/genetics/143.3.1409 ◽

1996 ◽

Vol 143 (3) ◽

pp. 1409-1416 ◽

Cited By ~ 1

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.

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Genetic parameters of Barki sheep raised under semi-arid conditions

Animal Science ◽

10.1017/s0003356100027008 ◽

1969 ◽

Vol 11 (3) ◽

pp. 361-367 ◽

Cited By ~ 9

Author(s):

M. H. Fahmy ◽

E. Salah E. Galal ◽

Y. S. Ghanem ◽

S. S. Khishin

Keyword(s):

Genetic Parameters ◽

Genetic Correlations ◽

Research Station ◽

Phenotypic Correlations ◽

Arid Conditions ◽

Body Weights ◽

Genetic And Phenotypic Correlations ◽

Fleece Weight ◽

Semi Arid ◽

Desert Research

SUMMARYRecords on 695 lambs were collected over a period of 5 years from 1961/62 to 1965/66, at Ras El-Hekma Desert Research Station, 230 km west of Alexandria. The characters studied were birth, weaning and yearling body weights, pre- and post-weaning daily gains and greasy fleece weight.Birth, 120-day and 365-day body weights were 3·4, 18·2 and 33·4 kg respectively. Greasy fleece weight at 16 months of age was 3·29 kg. Heritability estimates of birth, weaning, yearling weights, pre- and post-weaning daily gains and greasy fleece weight were 0·22, 0·45, 0·41,0·45 and 0·29 respectively. Genetic and phenotypic correlations between birth, weaning and yearling weights were all positive and significant. Genetic correlations between fleece weight and body characteristics were negative and low.

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Genetic variability for girth growth and rubber yield in Hevea brasiliensis

Scientia Agricola ◽

10.1590/s0103-90162006000300006 ◽

2006 ◽

Vol 63 (3) ◽

pp. 246-254 ◽

Cited By ~ 32

Author(s):

Paulo de Souza Gonçalves ◽

Marcelo de Almeida Silva ◽

Ligia Regina Lima Gouvêa ◽

Erivaldo José Scaloppi Junior

Keyword(s):

Hevea Brasiliensis ◽

Genetic Parameters ◽

Genetic Correlations ◽

Basic Knowledge ◽

Environment Interaction ◽

Genetic Characteristics ◽

Genotype Environment Interaction ◽

Genetic And Phenotypic Correlations ◽

High Heritability ◽

Selection Intensities

Basic knowledge of genetic characteristics of populations is necessary to conduct effective breeding and selection. The objective of this paper is describing the genetic variation of rubber yield and the correlation with other traits, and estimating the genetic parameters for girth growth and total number of latex vessels. Sixty seven clones of Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg. were tested at five sites during 10 years. Characters girth growth at panel opening and rubber yield, showed broad sense heritability on plot mean level, from 0.32 to 0.66 and 0.59 to 0.92, respectively. Predicted genetic gains equal to 0.73 cm and 0.79 g increase respectively on girth and yield in the opening panel and mature phases seems realistic, even with moderate selection intensities. Genetic correlations with rubber yield, bark thickness and total number of latex vessels were very large, and almost no genotype-environment interaction was present for girth growth. High genotype-environment interaction was present for rubber yield with genetic and phenotypic correlations across the sites, ranging from 0.64 to 0.92 (genetic) and 0.63 to 0.89 (phenotypic). Total number of latex vessels rings had a high heritability, ranging from 20.0% to 64.0% in the sites E and B, respectively.

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EFFECT OF FIXED FACTORS AND ESTIMATION OF GENETIC PARAMETERS OF GROWTH TRAITS FOR MOUNTAIN KIDS

IRAQI JOURNAL OF AGRICULTURAL SCIENCES ◽

10.36103/ijas.v50i6.843 ◽

2019 ◽

Vol 50 (6) ◽

Author(s):

Hermiz & Baper

Keyword(s):

Variance Components ◽

Fixed Effects ◽

Genetic Parameters ◽

Maximum Likelihood Method ◽

Growth Traits ◽

Genetic Correlations ◽

Likelihood Method ◽

Phenotypic Correlations ◽

Body Weights ◽

Genetic And Phenotypic Correlations

Body weights at birth (469), weaning (394) and at six month of age (358) for kids utilized in this study were raised at private project in Duhok governorate, Iraq during two kidding season (2016-2017) and (2017-2018). GLM within SAS programme was used to analyze the data which include the fixed effects (age of doe, year and season of kidding, sex of kid and type of birth, regression on doe weight at kidding, and the regression of later weights of kids on earlier weights) influencing the studied traits. Restricted Maximum Likelihood Method was used to estimate repeatability, heritability, genetic and phenotypic correlations after adjusting the records for fixed effects. Variance components of random effects were tested for positive definite. Overall mean of weights at birth (BWT), weaning (WWT) and 6 month of age (WT6M) were 2.92, 15.32 and 24.45 kg, respectively. Differences among groups of age of doe in all studied traits were not significant, while year of kidding and sex of kid affect all traits significantly (p<0.01). Season of kidding affect BWT and WWT significantly (P<0.01). Single born kids were heavier (P<0.01) than twins in BWT only. Regression of BWT on doe weight at kidding (0.033 kg/kg) was significant (P<0.01), while the regressions of WWT and WT6M were not significant. The regression coefficients of WWT on BWT (1.906 kg/kg) and of WT6M on WWT (0.835 kg/kg) were highly significant (P<0.01). Repeatability estimates for BWT, WWT and WT6M were 0.47, 0.45 and 0.35, respectively; on the same order the estimates of heritability were 0.41, 0.61 and 0.79. Genetic correlations between BWT with each of WWT (0.45) and WT6M (0.55), and between WWT and WT6M (0.68) were highly significant. All phenotypic correlations between each pair of body weights were higher than genetic correlations and ranged between 0.48 and 0.73.

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GENETIC ASPECTS OF PREWEANING PERFORMANCE OF NDAMA CATTLE

Nigerian Journal of Animal Production ◽

10.51791/njap.v11i2.2545 ◽

2021 ◽

Vol 11 (2) ◽

pp. 151-155

Author(s):

A. O. Leigh ◽

O. Akinokun ◽

S. A. Adeyanju

Keyword(s):

Birth Weight ◽

Beef Cattle ◽

Genetic Parameters ◽

Weaning Weight ◽

Livestock Farm ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Daily Gain

Records on birth weight (BW), preweaning daily gain (PWG) and weaning weight (WW) of Ndama beef cattle were obtained from the Fashola Livestock Farm in Oyo State of Nigeria between 1954 and 1964 and were analyzed to estimate the phenotypic and genetic parameters of preweaning performances of this breed of cattle. For birth weight, preweaning daily gain and weaning weight respectively heritability was estimated as 0.13 ± 0.08, 0.30 ± 0.14 and 0.25 ± 0.12 from paternal half-sib relationship. The estimates of genetic and phenotypic correlations obtained from these data among the three pre-weaning traits were found to be similar to those already in the general literature on beef cattle.

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Estimation genetic and phenotypic correlations between weight traits pre and post weaning weight in Baluchi sheep

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200019748 ◽

2007 ◽

Vol 2007 ◽

pp. 71-71

Author(s):

Mojtaba Hosseinpour Mashhadi ◽

Mehdi Aminafshar ◽

Nafise Tabasi

Keyword(s):

Genetic Parameters ◽

Genetic Parameter ◽

Harsh Environment ◽

Economic Traits ◽

Weaning Weight ◽

Sheep Population ◽

Phenotypic Correlations ◽

Native Breed ◽

Hot Climate ◽

Genetic And Phenotypic Correlations

Baluchi is the most common native breed of sheep in Iran, comprising 30% of the sheep population. This breed is native to the eastern part of the country, which has a dry and hot climate. The animals have had to adapt to the harsh environment. In order to improve efficiency, the performance of the animals for economic traits is used to estimate genetic parameters and selection in some nucleus flocks. The genetic and phenotypic correlations between weight traits have been reported for different breeds. The objective of this investigation is to estimate the genetic parameter and genetic and phenotypic correlations between weight traits.

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Genetic parameters for faecal egg count following mixed, natural, predominantly Ostertagia circumcincta infection and relationships with live weight in young lambs

Animal Science ◽

10.1017/s1357729800015319 ◽

1996 ◽

Vol 63 (3) ◽

pp. 423-428 ◽

Cited By ~ 116

Author(s):

S. C. Bishop ◽

K. Bairden ◽

Q. A. McKellar ◽

M. Park ◽

M. J. Stear

Keyword(s):

Genetic Parameters ◽

Genetic Correlations ◽

Live Weight ◽

Gastrointestinal Parasites ◽

Phenotypic Correlations ◽

Selection Decisions ◽

Faecal Egg Count ◽

Resistance To Infection ◽

Faecal Egg Counts ◽

Small Measurement Error

AbstractFaecal egg counts and live weights were measured on approximately 200 predominantly twin-born Scottish Blackface lambs each year for 3 years, from 1 to 6 months of age. Measurements were made at 4-week intervals following anthelmintic treatment. Heritability estimates (with s.e.s) of log transformed faecal egg count at each age were 0·01, 0·00, 0·12 (0·10), 0·14 (0·12), 0·15 (0·07) and 0·22 (0·13), for ages 1 to 6 months respectively. Therefore, genetic variation exists for acquired but apparently not for innate resistance to infection. Maternal common environmental effects (with s.e.s) were 0·36 (0·11), 0·20 (0·05), 0·27 (0·09), 0·06 (0·08), 0·15 (0·09) and 0·16 (0·08), for ages 1 to 6 months respectively. Genetic correlations between faecal egg counts in lambs older than 3 months were not significantly less than 1·0, indicating that faecal egg counts at different ages are expressions of the same trait. Phenotypic correlations between faecal egg counts were generally positive but small. Measurement error contributed one-third of the observed variation for individual egg counts. The heritability of mean faecal egg count from 3 to 6 months was 0·33 (s.e. 0·15), indicating that selection decisions can be made more accurately using multiple egg counts per animal. Phenotypic correlations between faecal egg counts and live weight were generally negative but close to zero. However, genetic correlations between faecal egg counts and live weight in lambs older than 3 months were close to -1·0, indicating that resistance to gastrointestinal parasites may be an important genetic determinant of growth rate in this environment.

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Genetic parameters of yield and morphological fruit and stone properties in apricot

Genetika ◽

10.2298/gensr0703315m ◽

2007 ◽

Vol 39 (3) ◽

pp. 315-324 ◽

Cited By ~ 4

Author(s):

Evica Mratinic ◽

Vera Rakonjac ◽

Dragan Milatovic

Keyword(s):

Correlation Analysis ◽

Genetic Correlation ◽

Genetic Parameters ◽

Ecological Factors ◽

Fruit Weight ◽

Genetic Differences ◽

Total Variance ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Significant Yield

Yield, fruit and stone weight and dimensions were studied in 24 apricot cultivars over a four-year period, to determine components of variability, heritability and genetic and phenotypic correlations. The analysis of the components of total variance evidenced that genetic differences between cultivars determined to the highest percentage the variability of fruit height and stone weight and dimensions, whereas the variation of yield, and fruit weight, breadth and thickness was predominantly determined by ecological factors. The values of heritability coefficients, in a broader sense, were found to be relatively high for fruit and stone weight and dimensions (88-93%), and medium for yield (48%). It was established by correlation analysis that all genetic and phenotypic coefficients of correlation between fruit and stone weight and dimensions were positive and statistically very significant. Yield was in a very significant, positive genetic correlation with a majority of studied characters except for fruit breadth. However, the phenotypic coefficients of correlation between those properties were not statistically significant.

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Estimates of genetic parameters of growth rate in sheep with reference to the method of estimation

Animal Production ◽

10.1017/s0003356100026003 ◽

1968 ◽

Vol 10 (1) ◽

pp. 109-112 ◽

Cited By ~ 1

Author(s):

E. Salah ◽

E. Galal

Keyword(s):

Growth Rate ◽

Body Weight ◽

Birth Weight ◽

Genetic Parameters ◽

Regression Coefficient ◽

Research Station ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Heritability Estimates ◽

Desert Research

There were 563 lambs in the study. They were single Barki lambs born during the period 1961–62 to 1965–66 in Ras El-Hekma Desert Research Station (U.A.R.). All lambs were weighed at birth and at weaning. From 1963–64 onward lambs were weighed nearly every 15 days.Two methods of estimating growth rate were compared:R1 = weaning weight — birth weight/age at weaningand R2 = the regression coefficient of weight on age. The effect of method of estimation on heritabilities and genetic and phenotypic correlations was examined.Heritability estimates of birth weight, R1 and genetic and phenotypic correlations between them were 0·18 ± 0·10, 0·24 ± 0·11, 0·50 and 0·12 respectively. From the data collected during the period 1963–64 to 1965–66 alone the heritability estimates of birth weight, R1 and R2 and the genetic and phenotypic correlations between birth weight and each of R1 and R2 were 0·15 ± 0·14, 0·39 ± 0·20 and 0·39 ± 0·20; 0·84 and 0·96; 0·28 and 0·27 respectively.For preweaning growth rate the method of dividing the gain in weight until weaning by age at weaning was virtually as good a method as using the regression of body weight on age. The correlation between the two methods was estimated as 0·91.

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

The Journal of Agricultural Science ◽

10.1017/s0021859600042015 ◽

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.

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