scholarly journals DIRECT AND MATERNAL GENETIC PARAMETERS AND GENETIC TRENDS FOR SOME BODY WEIGHTS AND GROWTH TRAITS IN BARKI SHEEP

2014 ◽  
Vol 51 (3) ◽  
pp. 186-195
Keyword(s):  
Genetic Parameters ◽  
Growth Traits ◽  
Body Weights ◽  
Genetic Trends

scholarly journals Estimates of (co)variance components and genetic parameters for body weights and growth efficiency traits in the New Zealand white rabbit

2017 ◽  
Vol 25 (4) ◽  
pp. 329 ◽  
Author(s):  
M. Sakthivel ◽  
D. Balasubramanyam ◽  
P. Kumarasamy ◽  
H. Gopi ◽  
A. Raja ◽  
...  
Keyword(s):  
Body Weight ◽  
New Zealand ◽  
Variance Components ◽  
Environmental Effect ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Effect ◽  
Growth Efficiency ◽  
Body Weights ◽  
Heritability Estimates

The genetic parameters of growth traits in the New Zealand White rabbits kept at Sheep Breeding and Research Station, Sandynallah, The Nilgiris, India were estimated by partitioning the variance and covariance components. The (co)variance components of body weights at weaning (W42), post-weaning (W70) and marketing (W135) age and growth efficiency traits viz., average daily gain (ADG), relative growth rate (RGR) and Kleiber ratio (KR) estimated on a daily basis at different age intervals (42 to 70 d; 70 to 135 d and 42 to 135 d) from weaning to marketing were estimated by restricted maximum likelihood, fitting 6 animal models with various combinations of direct and maternal effects. Data were collected over a period of 15 yr (1998 to 2012). A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for W42, W70 and W135 were 0.42±0.07, 0.40±0.08 and 0.27±0.07, respectively. Heritability estimates of growth efficiency traits were moderate to high (0.18 to 0.42). Of the total phenotypic variation, maternal genetic effect contributed 14 to 32% for early body weight traits (W42 and W70) and ADG1. The contribution of maternal permanent environmental effect varied from 6 to 18% for W42 and for all the growth efficiency traits except for KR2. Maternal permanent environmental effect on most of the growth efficiency traits was a carryover effect of maternal care during weaning. Direct maternal genetic correlations, for the traits in which maternal genetic effect was significant, were moderate to high in magnitude and negative in direction. Maternal effect declined as the age of the animal increased. The estimates of total heritability and maternal across year repeatability for growth traits were moderate and an optimum rate of genetic progress seems possible in the herd by mass selection. The genetic and phenotypic correlations among body weights and between growth efficiency traits were also estimated. Moderate to high heritability and higher genetic correlation in body weight traits promise good scope for genetic improvement provided measures are taken to keep the inbreeding at the lowest level.

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

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.

scholarly journals Estimation of phenotypic and genetic trends of the growth traits in Lipska and Svrljig sheep

2012 ◽  
Vol 28 (4) ◽  
pp. 743-749
Author(s):  
V. Caro-Petrovic ◽  
M.P. Petrovic ◽  
M.M. Petrovic ◽  
Z. Ilic ◽  
N. Maksimovic ◽  
...  
Keyword(s):  
Body Weight ◽  
Growth Traits ◽  
Genetic Correlations ◽  
The Body ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
First Time ◽  
Genetic Trends ◽  
Birth Type

Some phenotypic and genetic trends on growth traits of lambs are observed. The research implicated lambs of two local breeds of sheep: Lipska (LP) and Svrljig (SV). All lambs were weighed for the first time at birth (BWB), and thereafter, regularly in two-week intervals. On the basis of the results during weighing the body weight (BW) were adjusted to the average age: 30 (BW30), 60 (BW60) and 90 days (BW90). Results of the effect of genotype on growth showed a significant effect on the growth traits. Sex of lambs had a significant effect at birth and very significant effect at 30 days, but had no significant effect on weight at 60 (BW60) and 90 (BW90) days. Birth type had significant effect on the body weight from birth to weaning and the highest body weights were recorded in singles. Phenotypic correlations were positive and very highly significant between the growth traits. Genetic correlations were significant, but not between all observed ages of lambs.

scholarly journals Analysis of genetic parameters and genetic trends for early growth traits in Iranian Afshari sheep

2018 ◽  
Vol 34 (3) ◽  
pp. 289-301
Author(s):  
Meysam Latifi ◽  
Ali Mohammadi
Keyword(s):  
Genetic Improvement ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Early Growth ◽  
Information Criteria ◽  
Daily Weight Gain ◽  
Data Set ◽  
Female Birth ◽  
Genetic Trends

The purpose of the present study was estimation of genetic parameters and genetic trends of early growth traits using Bayesian approach by Gibbs3f90 software in Iranian Afshari sheep. The data set [birth weight (BW), weaning weight (WW) and pre-weaning daily weight gain (PWDG)] were collected during the period 1999 to 2010 from Agriculture Jahad of Zanjan province, Iran. The fitted fixed effects were herd-year-season as interactions, sex (male, female), birth type (single, multiple) and age of dam. Based on Derivative Information Criteria (DIC), for studied traits the most appropriate model was determined. Therefore, based on the most appropriate fitted model, the direct additive heritabilities estimate for BW, WW and PWDG were 0.32?0.02, 0.05?0.01 and 0.24?0.02, respectively. The estimates of maternal heritabilities were 0.17?0.04, 0.07?0.02 and 0.12?0.05 and total heritabilities 0.11?0.05, 0.08?0.02 and 0.08?0.03 for BW, WW and PWDG, respectively. Direct genetic trends were positive for all traits but only significant for BW 0.75?0.31 g/year (P <0.05). Also, maternal genetic trends were for all traits negative and was significant for BW -0.63?0.27 g/year (P <0.05). The moderate estimates of heritabilities for early growth traits indicate that in Afshari sheep faster genetic improvement through selection is possible for these traits. Furthermore, the results genetic trends in this current study indicated that genetic improvement through selection is suitable only for BW in Afshari sheep.

scholarly journals Genetic parameters and genetic trends for growth traits of the Red Maasai sheep and its crosses to Dorper sheep under extensive production system in Kenya

2022 ◽  
Vol 206 ◽  
pp. 106588
Author(s):  
Edwin Oyieng ◽  
Raphael Mrode ◽  
Julie M.K. Ojango ◽  
Chinyere C. Ekine-Dzivenu ◽  
James Audho ◽  
...  
Keyword(s):  
Production System ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Dorper Sheep ◽  
Genetic Trends

Estimation of genetic parameters for body weight traits and litter size of Moghani sheep, using a Bayesian approach via Gibbs sampling

2010 ◽  
Vol 148 (3) ◽  
pp. 363-370 ◽  
Author(s):  
N. GHAVI HOSSEIN-ZADEH ◽  
M. ARDALAN
Keyword(s):  
Body Weight ◽  
Gibbs Sampling ◽  
Litter Size ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Residual Effects ◽  
Pedigree Information ◽  
Body Weights

SUMMARYThe objective of the present study was to estimate genetic parameters for body weights at different ages and litter size (LS) in Moghani sheep. Traits included were birth weight (BW), 3 months weight (3MW), 6 months weight (6MW), 9 months weight (9MW), yearling weight (YW) and LS. The data of 6659 lambing records and pedigree information used in the current programme were collected at the Breeding Station of Moghani sheep (Ardebil province, Iran) during 1987–2005. Different linear and threshold animal models with additive genetic, maternal genetic, maternal permanent environmental and residual effects were implemented by Gibbs sampling (GS) methodology. A single GS chain with 150 000 rounds was generated by the MTGSAM program. The posterior means of genetic parameters were estimated based on the 1300 samples that were left after elimination of 20 000 rounds in the burn-in period and 100 rounds of each thinning interval. Posterior mean estimates of direct heritability were 0·29, 0·13, 0·14, 0·10, 0·31 and 0·10, while those of maternal heritabilities were 0·29, 0·08, 0·11, 0·06, 0·10 and 0·17 for BW, 3MW, 6MW, 9MW, YW and LS, respectively. Genetic correlations among the growth traits and LS were negative for direct genetic and maternal genetic effects. Therefore, selection for increased growth or LS may have a negative genetic effect on the other traits. The medium to high negative estimates of direct–maternal correlations for body weight traits or LS suggest that it would be difficult to improve direct and maternal growth ability jointly for Moghani sheep.

scholarly journals Estimates of genetic parameters for growth traits of local Hamra breed threatened with extinction in southwestern arid rangeland of Algeria

2018 ◽  
Vol 34 (4) ◽  
pp. 433-441
Author(s):  
Houari Yerou ◽  
Hakim Ouldouelhadj ◽  
Abdelrahmane Berber ◽  
Amine Mokadem ◽  
Bachir Koudad
Keyword(s):  
Animal Models ◽  
Data Base ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
Covariance Components ◽  
Variance And Covariance Components

The data base for body weights and growths of 411 Hamra lambs were used to estimate genetic parameters. These lambs were obtained from 31 rams and 493 ewes between 2012 and 2017. Traits analysed were weights at birth (BW), 30 days (W30), 90 days (W90) of age, and average daily gains from 10 to 30 (ADG10-30) and30-90 (ADG30-90) days. REML estimates of variance and covariance components were obtained assuming animal models that included the fixed effects for year-type of birth (2012 single, 2012 twin, . ., 2017 single, 2017 twin), sex (male, female), and ewes age at lambing (< 18, 18-30, 30-42, 42-54, >54 months). Heritabilities were 0.12, 0.06 and 0.11 respectively for BW, W3Oand W90and the average daily gains were 0.05 and 0.17 for ADG0-30and ADG30-90. The estimates of genetic correlations showed no genetic antagonisms among the growth traits. The genetic correlations estimated were positive and medium to high, except those between ADG30-90 and ADG0-30 and between ADG30-90 and W30 which were slightly negative. Phenotypic correlations were positive and ranged from 0.12 to 0.85. They were high between adjacent weights and between ADG and their corresponding weights.

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