scholarly journals Effectiveness of Genetic Parameter Estimation in a Small Flock of Merino Sheep with Shallow Pedigree

2020 ◽  
Vol 8 (4) ◽  
pp. 920-926
Author(s):  
Serdar Duru ◽  
Mehmet Koyuncu
Keyword(s):  
Growth Traits ◽  
Genetic Parameter ◽  
Average Daily Gain ◽  
Information Criterion ◽  
Suitable Model ◽  
Merino Sheep ◽  
Kleiber Ratio ◽  
Sources Of Variation ◽  
Maternal Heritability ◽  
Daily Gain

In this study, the genetic and non-genetic parameters were estimated for growth traits of Karacabey merino sheep. Growth performance data refer to 1863 lambs born between 2016 and 2018. Analyses were carried out by restricted maximum likelihood fitting animal models and disregarding or including maternal genetic or maternal permanent environmental effect. Six different animal model were fitted for all traits, and the most suitable model for each trait was chosen after Akaike information criterion test (AIC). Year of birth, age of dam, type of birth and lamb sex were significant sources of variation on birth weight (BW), average daily gain (ADG), Kleiber ratio (KR), weaning weight (WW) and six month weight (6MW). Direct heritability (h^2) for BW, ADG and 6MW were 0.12, 0.02 and 0.04, respectively, however, for KR and WW were 0.00 model 6 (which the best). The estimates of maternal heritability (m^2) for ADG, KR and WW were 0.12, 0.04 and 0.04, respectively in model 5, also maternal heritability were low for BW and 6MW. Maternal permanent environmental effects (c^2) have high contribution to the explanation growth traits and were estimated between 0.19 and 0.75 for these traits. These results showed that selecting for improved maternal and/or direct effects for Karacabey merino in the herd would generate very slow genetic improvement in growth traits.

Genetic parameters for growth rate and Kleiber ratios of Nellore sheep

2018 ◽  
Author(s):  
I. Satish Kumar ◽  
G. Gangaraju ◽  
C. Vijaya Kumar ◽  
Sapna Nath
Keyword(s):  
Andhra Pradesh ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Research Station ◽  
Genetic Progress ◽  
Stages Of Growth ◽  
Kleiber Ratio ◽  
Nellore Sheep ◽  
Daily Gain

Data on growth traits of Nellore sheep were extracted from the records maintained at Livestock Research Station, Palamaner, Andhra Pradesh, India for a period of five years. The genetic and phenotypic parameters were estimated for growth traits i.e., average daily gain (ADG) from birth to 3 months (ADGa), 3 months to 6 months (ADGb), 6 to 12 months (ADGc) and the corresponding Kleiber ratio (KR) at respective stages of growth. The non genetic factors included in the model were having significance on most of the traits studied. The heritability estimates for ADG and corresponding KR ranged from 0.17 to 0.25. The estimates of genetic correlations among the traits ranged between -0.28 (Ka-Kb) and 0.99 (ADGb-Kb). The moderate estimates of heritability, high and positive genetic correlations among the traits in the study were suggestive of moderate genetic progress in the Nellore breed of sheep through selection.

Genetic parameter estimates for early growth traits in Naeini goat

2012 ◽  
Vol 52 (11) ◽  
pp. 1046 ◽  
Author(s):  
Hasan Baneh ◽  
Mojtaba Najafi ◽  
Ghodrat Rahimi
Keyword(s):  
Environmental Effects ◽  
Variance Components ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Parameter ◽  
Average Daily Gain ◽  
Parameter Estimates ◽  
Estimate Variance ◽  
Daily Gain ◽  
Birth Type

The present study was carried out to estimate variance components for growth traits in Naeini goats. Bodyweight records were collected for two flocks under supervision of the Agriculture Organisation of the Esfahan province between 2000 and 2007. Investigated traits were birthweight (BW; n = 2483), weaning weight (WW; n = 1211) and average daily gain from birth to weaning (ADG; n = 1211). Environmental effects were investigated using fixed-effect models, while (co)variance components and genetic parameters were estimated with single- and three-trait analyses using REML methods and WOMBAT software. Six different animal models were fitted to the traits, with the best model for each trait determined by log-likelihood ratio tests (LRT). All traits were significantly influenced by herd, birth year, sex of the kid, birth type and dam age (P < 0.01). On the basis of LRT, maternal permanent environmental effects (c2) were significant for WW and ADG, while BW was affected only by direct genetic effects. Direct heritability estimates for BW, WW and ADG were 0.25 ± 0.05, 0.07 ± 0.06 and 0.21 ± 0.11, respectively. The estimate of c2 was 0.16 ± 0.06 for both WW and ADG. Estimates of genetic correlation for BW–ADG, BW–WW and ADG–WW were 0.49, 0.61 and 0.94, respectively. The estimated phenotypic correlations were positive and were between 0.03 (BW–ADG) and 0.95 (ADG–WW). These results indicate that selection can be used to improve growth traits in this goat breed.

scholarly journals Genetic parameters for direct and maternal effects on growth traits of sheep

2012 ◽  
Vol 55 (6) ◽  
pp. 603-611 ◽  
Author(s):  
F. Ghafouri-Kesbi ◽  
H. Baneh
Keyword(s):  
Maternal Effects ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Information Criterion ◽  
Phenotypic Variance ◽  
Environmental Variance ◽  
Daily Gain

Abstract. The aim of the present study was to estimate (co)variance components and corresponding genetic parameters for birth weight (BW), weaning weight (WW), 6-month weight (W6), 9-month weight (W9), average daily gain from birth to weaning (WWDG), average daily gain from weaning to 6 months (W6DG) and average daily gain from 6 months to 9 months (W9DG) for a nucleus flock of Iranian Makooei sheep. Genetic parameters were estimated by REML procedure fitting six animal models including various combinations of maternal effects. The Akaike information criterion (AIC) was used to determine the most appropriate model. Estimates of direct heritability (h2) ranged from 0.13 (W6DG) to 0.32 (BW). Maternal effects were found to be important in the growth performance of the Makooei sheep, indicating the necessity of including maternal effects in the model to obtain accurate estimates of direct heritability. Estimates of maternal heritability (m2) ranged from 0.05 (W6) to 0.16 (WWDG) and the estimates of proportion of maternal permanent environmental variance to phenotypic variance (c2) were in the range between 0.05 (BW) and 0.10 (W6). Direct additive genetic correlations were positive in all cases and ranged from 0.00 (BW/W9DG) to 0.99 (WW/WWDG). Phenotypic correlations showed a broad range from −0.27 (WW/W9DG) to 0.99 (WW/WWDG). Estimates of genetic parameters showed that genetic improvement through selection programs is possible. WW would be a suitable selection criterion since it has acceptable direct heritability and relatively high genetic correlation with other traits.

Average daily gain and kleiber ratio in Bharat merino sheep

2019 ◽  
Vol 25 (2) ◽  
pp. 151
Author(s):  
P.K. Mallick ◽  
I.S. Chauhan ◽  
G.R. Gowane ◽  
P. Thirumurgan ◽  
G. Murali ◽  
...  
Keyword(s):  
Average Daily Gain ◽  
Merino Sheep ◽  
Kleiber Ratio ◽  
Daily Gain

scholarly journals Non-genetic factor and genetic parameter analysis for growth traits in Sumba Ongole (SO) cattle

2018 ◽  
Vol 43 (2) ◽  
pp. 94 ◽  
Author(s):  
W.P.B. Putra ◽  
P.P. Agung ◽  
S. Said
Keyword(s):  
Generalized Linear Model ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Parameter ◽  
Average Daily Gain ◽  
Correlation Method ◽  
Genetic Effect ◽  
Parameter Analysis ◽  
High Category ◽  
Daily Gain

The aim of this study was to evaluate non-genetic factors and genetic parameters of the growth traits in Sumba Ongole (SO) cattle. The growth traits were consisted of birth weight (BW), weaning weight (WW), yearling weight (YW), average daily gain of pre-weaning (ADG1) and post-weaning (ADG2). Data from 143 heads of SO cattle (year 2011 to 2016) which raised at PT KAR were used in this study. Generalized Linear Model (GLM) analysis was performed to evaluate non-genetic effect including sex, year of birth, generation and season. Therefore, to evaluate genetic parameters, the heritability (h2) and genetic correlation (rg ) were performed using Paternal Halfshib Correlation method. The results showed that sex of calf had no significant effect (P>0.05) on BW, WW and YW, but year of birth had significant effect on those traits. The factor of season had significant effect on WW. The estimation of h2 values of growth traits were included high category (h2>0.30) and accurate (h2>SE) on BW (0.66±0.42), WW (0.65±0.44), YW (0.67±0.42), ADG1 (0.68±0.45) and ADG2 (0.70±0.43). The estimation of rg values were included high category (rg>0.50) and accurate (rg>SE) on BW-WW (0.87±0.63); BW-YW (0.95±0.87); ADG1-WW (0.99±0.34); WW-YW (0.98±0.48) and ADG1-YW (0.95±0.51). It was concluded that trait of WW could be used as selection criteria to increase YW trait in SO cattle. 

Effects of dietary energy planes on growth and heritability estimates for postweaning growth traits in young beef bulls

1995 ◽  
Vol 75 (3) ◽  
pp. 469-472
Author(s):  
D. R. C. Bailey ◽  
M. F. Liu ◽  
N. H. Shannon
Keyword(s):  
Growth Rate ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Dietary Energy ◽  
Relative Growth ◽  
Heritability Estimates ◽  
Energy Plane ◽  
Maternal Heritability ◽  
Daily Gain

Records of young AN and young HE bulls were analyzed to evaluate the influences of dietary energy planes on growth and heritability estimates of growth traits during 168-d postweaning test. Estimates of h2a for end of test weight (WT168), average daily gain on test (ADG 0–168) and relative growth rate on test (RGR 0–168) were much higher in the MED line than in the HED line. Between lines, maternal heritability estimates (h2m) for WT0 and ADG 0–168 were similar. Estimates of h2m for WT168 was much higher in the HED line than in the MED line. All direct-maternal genetic correlations (ram) were negative. These results may indicate that the antagonism between direct and maternal genetic effects for postweaning growth traits in the MED line was much less than that in the HED line. Key words: Beef cattle, energy plane, growth, heritability

scholarly journals Model comparisons and genetic parameter estimates of growth and the Kleiber ratio in Shal sheep

2013 ◽  
Vol 56 (1) ◽  
pp. 264-275 ◽  
Author(s):  
H. Mohammadi ◽  
M. M. Shahrebabak ◽  
H. M. Shahrebabak ◽  
A. Bahrami ◽  
M. Dorostkar
Keyword(s):  
Maternal Effects ◽  
Growth Traits ◽  
Genetic Parameter ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Parameter Estimates ◽  
Phenotypic Variance ◽  
Kleiber Ratio ◽  
Lamb Growth

Abstract. Genetic and phenotypic parameters were estimated for lamb growth traits for the Shal sheep using an animal model. Data on lamb growth performance were extracted from available performance records at the Shal sheep Station in Qazvin, Iran. Studied traits were body weights of lambs at birth (BW), at 3 months of age as weaning weight (WW), 6 months weight (6MW), 9 months weight (9MW), yearling weight (YW), average daily gain from birth to weaning (ADG) and Kleiber ratio from birth to weaning (KR). Significant random effects for each trait were determined by fitting additive direct genetic effects, additive maternal effects, covariance between additive direct and additive maternal effects, maternal permanent environmental and maternal temporary environmental (common litter) effects under twelve animal models. Univariate analyses were carried out under the most appropriate model, determined by AIC test. Direct heritability estimates for BW, WW, ADG, KR, 6MW, 9MW and YW were 0.13, 0.19, 0.18, 0.05, 0.16, 0.18 and 0.19, respectively. Maternal additive genetic effects were fitted only for BW and WW; corresponding estimates of 0.12 and 0.10 obtained for maternal heritability of BW and WW, respectively. Maternal permanent environmental effects have low contribution in expression of KR and lead to estimates of 0.06 and 0.06 for maternal permanent environmental variance as a proportion of phenotypic variance (c2) of these traits, respectively. All pre-weaning traits, except KR, were affected by litter effects. The magnitude of ratio of common litter variance to phenotypic variance (l2) was 0.05, 0.12 and 0.14 for BW, WW and ADG, respectively. Direct genetic correlations were positive and ranged from 0.09 for KR-YW to 0.80 for WW-ADG; phenotypic ones ranged from 0.18 for KR-YW to 0.87 for WW-ADG.

scholarly journals Grid search approach to discriminate between old and recent inbreeding using phenotypic, pedigree and genomic information

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Pattarapol Sumreddee ◽  
El Hamidi Hay ◽  
Sajjad Toghiani ◽  
Andrew Roberts ◽  
Samuel E. Aggrey ◽  
...  
Keyword(s):  
Common Ancestor ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Recent Common Ancestor ◽  
Pedigree Information ◽  
Grid Search ◽  
Genomic Information ◽  
The Impact ◽  
Daily Gain ◽  
Harmful Effects

Abstract Background Although inbreeding caused by the mating of animals related through a recent common ancestor is expected to have more harmful effects on phenotypes than ancient inbreeding (old inbreeding), estimating these effects requires a clear definition of recent (new) and ancient (old) inbreeding. Several methods have been proposed to classify inbreeding using pedigree and genomic data. Unfortunately, these methods are largely based on heuristic criteria such as the number of generations from a common ancestor or length of runs of homozygosity (ROH) segments. To mitigate these deficiencies, this study aimed to develop a method to classify pedigree and genomic inbreeding into recent and ancient classes based on a grid search algorithm driven by the assumption that new inbreeding tends to have a more pronounced detrimental effect on traits. The proposed method was tested using a cattle population characterized by a deep pedigree. Results Effects of recent and ancient inbreeding were assessed on four growth traits (birth, weaning and yearling weights and average daily gain). Thresholds to classify inbreeding into recent and ancient classes were trait-specific and varied across traits and sources of information. Using pedigree information, inbreeding generated in the last 10 to 11 generations was considered as recent. When genomic information (ROH) was used, thresholds ranged between four to seven generations, indicating, in part, the ability of ROH segments to characterize the harmful effects of inbreeding in shorter periods of time. Nevertheless, using the proposed classification method, the discrimination between new and old inbreeding was less robust when ROH segments were used compared to pedigree. Using several model comparison criteria, the proposed approach was generally better than existing methods. Recent inbreeding appeared to be more harmful across the growth traits analyzed. However, both new and old inbreeding were found to be associated with decreased yearling weight and average daily gain. Conclusions The proposed method provided a more objective quantitative approach for the classification of inbreeding. The proposed method detected a clear divergence in the effects of old and recent inbreeding using pedigree data and it was superior to existing methods for all analyzed traits. Using ROH data, the discrimination between old and recent inbreeding was less clear and the proposed method was superior to existing approaches for two out of the four analyzed traits. Deleterious effects of recent inbreeding were detected sooner (fewer generations) using genomic information than pedigree. Difference in the results using genomic and pedigree information could be due to the dissimilarity in the number of generations to a common ancestor. Additionally, the uncertainty associated with the identification of ROH segments and associated inbreeding could have an effect on the results. Potential biases in the estimation of inbreeding effects may occur when new and old inbreeding are discriminated based on arbitrary thresholds. To minimize the impact of inbreeding, mating designs should take the different inbreeding origins into consideration.

scholarly journals Residual feed intake and relationships with performance of Nellore cattle selected for post weaning weight

2011 ◽  
Vol 40 (4) ◽  
pp. 929-937 ◽  
Author(s):  
T. Lucila Sobrinho ◽  
R.H. Branco ◽  
S.F.M. Bonilha ◽  
A.M. Castilhos ◽  
L.A. Figueiredo ◽  
...  
Keyword(s):  
Body Weight ◽  
Standard Deviation ◽  
Feed Intake ◽  
Average Daily Gain ◽  
Residual Feed Intake ◽  
Feed Conversion ◽  
Relative Growth ◽  
Kleiber Ratio ◽  
Nellore Cattle ◽  
Daily Gain

The objective of this work was to evaluate performance, efficiency parameters and phenotypic correlations among measurements of energy efficiency of Nellore cattle selected for post weaning weight and classified according to residual feed intake, calculated by the difference between observed and predicted intake, based on average metabolic body weight and average daily gain. Thus, animals were classified within three groups: high (> mean + 0.5 standard deviation, less efficient); medium (±0.5 standard deviation of the mean); and low (< mean - 0.5 standard deviation, more efficient) residual feed intake. No differences were observed at initial and final body weights, average daily gain and dry matter intake among groups. Animals with low residual feed intake also had greater feed efficiency, feed conversion and partial efficiency of growth and did not differ from the other animals regarding to relative growth rate and Kleiber ratio. Residual feed intake was significantly correlated to feed efficiency (-0.25), feed conversion (0.25), partial efficiency of growth (-0.37) and dry matter intake (0.16) but it did not present significant correlation with body weight (0.04), average daily gain (-0.02), relative growth rate (-0.03) and Kleiber ratio (-0.05). Significant correlations were found between feed conversion and initial body weight (0.34) and average daily gain (-0.46). Partial efficiency of growth presented significant correlation with all other efficiency parameters analyzed. Residual feed intake has high potential in productive efficiency, when compared to the other energy efficiency measurements, being independent of growth and size of the animals.

scholarly journals (Co)variance components and genetic parameters for growth rate and Kleiber ratio in fat-tailed Mehraban sheep

2013 ◽  
Vol 56 (1) ◽  
pp. 564-572 ◽  
Author(s):  
F. Ghafouri-Kesbi
Keyword(s):  
Growth Rate ◽  
Variance Components ◽  
Genetic Parameters ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Phenotypic Variance ◽  
Genetic Progress ◽  
Kleiber Ratio ◽  
Derivative Free ◽  
Maternal Heritability

Abstract. The aim of the present study was to estimate (co)variance components and genetic parameters for average daily gain from birth to weaning (ADGa), weaning to 6 months (ADGb), weaning to 9 months (ADGc), 6 months to 9 months (ADGd) and corresponding Kleiber ratios (KRa, KRb, KRc and KRd) in Mehraban sheep. A derivative-free algorithm combined with a series of six univariate linear animal models was used to estimate phenotypic variance and its direct, maternal and residual components. In addition, bivariate analyses were done to estimate (co)variance components between traits. Estimates of direct heritability (h2) were 0.10, 0.11, 0.16, 0.09, 0.13, 0.13, 0.15 and 0.08 for ADGa, ADGb, ADGc, ADGd, KRa, KRb, KRc and KRd, respectively and indicate that in Mehraban sheep genes contribute very little to the variance of the growth rate and Kleiber ratio. Estimates of maternal heritability (m2) were 0.10, 0.08 and 0.05 for ADGa, KRa and KRb, respectively. Direct additive genetic correlations ranged from −0.32 (KRa-KRd) to 0.99 (ADGb-KRb) and phenotypic correlations ranged from −0.53 (ADGa- ADGd) to 0.99 (ADGa-KRa). Estimates of direct heritability and genetic correlations show that genetic improvement in efficiency of feed utilization through selection programmes is possible, though it would generate a relatively slow genetic progress.

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