scholarly journals A comparison between different selection indices for some productive traits on Egyptian buffaloes

2009 ◽  
Vol 52 (5) ◽  
pp. 476-484 ◽  
Author(s):  
K. A. M. Mourad ◽  
A. S. Khattab
Keyword(s):  
Animal Model ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Lactation Period ◽  
Environmental Correlations ◽  
Selection Indices ◽  
Total Milk ◽  
Production Research ◽  
Productive Traits

Abstract. A total of 2 262 normal lactation records of Egyptian buffaloes kept at Mehallet Mousa Farm belonging to Animal Production Research Institute, Ministry of Agriculture during the period from 1985 to 2003 were used to estimate phenotypic and genetic parameters for total milk yield (TMY, kg), lactation period (LP, day), birth weight (BW, kg) and weaning weight (WW, kg). In addition, eleven selection indices were constructed. Data were analyzed using multi trait animal model (MTAM). The model included individuals, permanent environmental and errors as random effects, month and year of calving and parity as fixed effects. Heritability estimates were 0.172, 0.134, 0.046 and 0.257 for TMY, LP, BW and WW, respectively. Genetic correlations among all traits studied are positive highly significant and ranged from 0.50 to 0.99. Permanent and temporary environmental correlations among all traits studied are similar to genetic correlations, while the correlations between WW and all traits studied are negative. Eleven selection indices were constructed, index I1 which incorporating TMY, LP, BW and WW or index I2 which incorporating TMY, LP and WW are the best (RIH =0.86), both indices are recommended to improve productive traits in Egyptian buffaloes.

scholarly journals Comparison of models for estimating genetic parameters and predicting breeding values for birth weight and calving ease in Czech Charolais cattle 

2014 ◽  
Vol 59 (No. 7) ◽  
pp. 302-309 ◽  
Author(s):  
L. Vostrý ◽  
Z. Veselá ◽  
A. Svitáková ◽  
H. Vostrá Vydrová
Keyword(s):  
Animal Model ◽  
Birth Weight ◽  
Beef Cattle ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Parameters Estimation ◽  
Calving Ease ◽  
Heritability Estimates

The most appropriate model for genetic parameters estimation for calving ease and birth weight in beef cattle was selected. A total of 27 402 field records were available from the Czech Charolais breed. For estimation of genetic parameters for calving ease and body weight, three bivariate models were tested: a linear-linear animal model (L-LM) with calving ease classified into four categories (1 – easy; 2–4 – most difficult), a linear-linear animal model (SC-LM) in which calving ease scores were transformed into Snell scores (Snell 1964) and expressed as percentage of assisted calving (ranging 0–100%), and a bivariate threshold-linear animal model (T-LM) with calving ease classified into four categories (1 – easy, 2–4 – most difficult). All tested models included fixed effects for contemporary group (herd × year × season), age of dam, sex and breed of a calf. Random effects included direct and maternal genetic effects, maternal permanent environmental effect, and residual error. Direct heritability estimates for calving ease and birth weight were, with the use of L-LM, SC-LM, and T-LM, from 0.096 ± 0.013 to 0.226 ± 0.024 and from 0.210 ± 0.024 to 0.225 ± 0.026, respectively. Maternal heritability estimates for calving ease and birth weight were, with the use of L-LM, SC-LM, and T-LM, from 0.060 ± 0.031 to 0.104 ± 0.125 and from 0.074 ± 0.041 to 0.075 ± 0.040, respectively. Genetic correlations of direct calving ease with direct birth weight ranged from 0.46 ± 0.06 to 0.50 ± 0.06 for all tested models; whereas maternal genetic correlations between these two traits ranged from 0.24 ± 0.17 to 0.25 ± 0.53. Correlations between direct and maternal genetic effects within-trait were negative and substantial for all tested models (ranging from –0.574 ± 0.125 to –0.680 ± 0.141 for calving ease and from –0.553 ± 0.122 to –0.558 ± 0.118 for birth weight, respectively), illustrating the importance of including this parameter in calving ease evaluations. Results indicate that any of the tested models could be used to reliably estimate genetic parameters for calving ease for beef cattle in the Czech Republic. However, because of advantages in computation time and practical considerations, genetic analysis using SC-LM (transformed data) is recommended.

scholarly journals Direct and Maternal Genetic Trends for Some Productive and Reproductive Traits in Egyptian Buffaloes

2020 ◽  
Vol 25 (1) ◽  
pp. 1
Author(s):  
Ibrahim Abu El- Naser
Keyword(s):  
Genetic Correlations ◽  
Reproductive Traits ◽  
Breeding Value ◽  
Lactation Period ◽  
Production Research ◽  
Days Open ◽  
Productive Traits ◽  
Set Up ◽  
Maternal Heritability ◽  
Daily Milk

This study was done to determine the direct and maternal genetic and phenotypic trends for productive traits such as first lactation milk yield (FLMY, kg), first lactation period (FLP, d) and first lactation daily milk (FLDM, kg), and reproductive traits such as age at first calving (AFC, mo), First days open (FDO, d) and first calving interval (FCI, d). Data were collected over consecutive 25 years (1991 to 2015) of 1104 first lactation of 135 sires and 482 dams maintained at Mahallet Mousa farms of Animal Production Research Institute. Data were analyzed by Animal model to determine genetic parameters for studied traits. Means of FLMY, FLP, FLDM, AFC, FDO and FCI were 1546.5kg, 189d, 7.9kg, 37.9mo, 120.8d and 428d, respectively. The direct heritability (h2a) for same traits were 0.25, 0.18, 0.24, 0.45, 0.18 and 0.19, respectively. Corresponding maternal heritability (h2m) for mentioned traits was 0.12, 0.19, 0.22, 0.25, 0.12 and 0.12, respectively. Genetic correlations (rg) among studied traits were varied between -0.19 to 0.38. Accuracy of predicted breeding value varied between 69 to 94, 0.37 to 94 and 42 to 91% for FLMY, FLP, FLDM, AFC, FDO and FCI of sires, cows and dams, respectively that revealed the genetic improvement could be actualized through each of cows or sires or dams. Additive and maternal genetic, permanent environmental and phenotypic trends were not significant for all studied traits. It indicated that it is important to set up a plan to improve genetic and environmental conditions thus, increasing productivity and realization of high profitability.

scholarly journals Genetic Analysis of Basic and Composite Reproduction Traits in Guilan Sheep

2017 ◽  
Vol 17 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Bahareh Eteqadi ◽  
Navid Ghavi Hossein-Zadeh ◽  
Abdol Ahad Shadparvar
Keyword(s):  
Litter Size ◽  
Fixed Effects ◽  
Production Efficiency ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Meat Production ◽  
Environmental Correlations ◽  
Litter Weight ◽  
The North

Abstract The objective of the present study was to estimate genetic parameters for reproductive traits in Guilan sheep. Data were comprised of 14,534 records of lambs from 136 sires and 2,021 dams which were collected during 1994 to 2011 by the Agriculture Organization of Guilan Province in the north of Iran. The basic reproductive traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), and litter mean weight per lamb weaned (LMWLW). The composite reproductive traits were total litter weight at birth per ewe lambing (TLWB) and total litter weight at weaning per ewe lambing (TLWW). The general linear model procedure of SAS was used for determining the fixed effects which had significant effect on the traits under study. The flock-year-season of lambing had significant effect on studied traits (P<0.01). The genetic parameters were estimated with repeatability animal model using restricted maximum likelihood (REML) procedure of the Wombat program. Direct heritability estimates were 0.00, 0.00, 0.01, 0.01, and 0.03 for LSB, LSW, LMWLW, TLWB, and TLWW, respectively, and corresponding repeatabilities were 0.2, 0.00006, 0.01, 0.972 and 0.034, respectively. Genetic correlation estimates between traits ranged from -0.99 for LSB-LSW to 0.99 for LMWLW-TLWW. Phenotypic correlations ranged from -0.09 for LSB-TLWB to 0.98 for LMWLW-TLWW and environmental correlations ranged from -0.03 for LSW-TLWW to 0.98 for LMWLW-TLWW. The results showed that strong positive genetic correlations of LMWLB and LMWLW with other traits may improve meat production efficiency in Guilan sheep. The low estimates of heritability and repeatability obtained for ewe productivity traits indicate that selection based on the ewe’s own performance may result in slow genetic improvement.

scholarly journals Genetic parameters and genetic gains for reproductive traits of Arabi sheep

2015 ◽  
Vol 31 (1) ◽  
pp. 23-36 ◽  
Author(s):  
H. Roshanfekr ◽  
P. Berg ◽  
K. Mohammadi ◽  
Mirza Mohamadi
Keyword(s):  
Litter Size ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Least Square ◽  
Research Station ◽  
Environmental Correlations ◽  
Breeding Values ◽  
Litter Weight

The current study reports, for the first time, the genetic parameters and genetic, phenotypic and environmental correlations and trends of reproductive traits in Arabi sheep. Data were collected at Animal Science Research Station of Khuzestan Ramin Agricultural and Natural Resources University (ASRSKRANRU), south-west of Iran from 2001 to 2008. Litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), litter mean weight per lamb weaned (LMWLW), total litter weight at birth (TLWB) and total litter weight at weaning (TLWW) averaged 1.11 lambs, 1.01 lambs, 3.83 kg, 19.43 kg, 4.16 kg and 20.12 kg, respectively. Genetic parameters and correlations were estimated with univariate and bivariate models using restricted maximum likelihood, breeding values of animals were estimated with best linear unbiased prediction (BLUP) and genetic- and phenotypic trends by regression of ewes? average breeding values and phenotypic least square means on year of birth respectively. Random effects were fitted by additive direct genetic effects and permanent environment related to the ewe as well as service sire effects, in addition to fixed effects of ewe age at lambing and lambing year. Heritability estimates of 0.05, 0.02, 0.13, 0.12, 0.04, and 0.06, and repeatability estimates of 0.08, 0.06, 0.17, 0.16, 0.14 and 0.21 for the six traits, respectively. Genetic correlations between traits varied from ?0.82 to 0.94. Phenotypic correlations were lower, ranging from ?0.33 to 0.52. Estimated annual genetic progress was very low; ?0.003 lambs for LSW and 15 g for TLWW. Annual phenotypic trend was only significant for LSW being 0.007 lambs. The study concluded that indirect selection based on total litter weight at weaning could be efficient for the traits studied.

Estimation of genetic parameters for litter size in sheep: a comparison of a repeatability and a multivariate model

1998 ◽  
Vol 66 (3) ◽  
pp. 685-688 ◽  
Author(s):  
M. J. de Vries ◽  
E. H. van der Waaij ◽  
J. A. M. van Arendonk
Keyword(s):  
Animal Model ◽  
Genetic Correlation ◽  
Litter Size ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Multivariate Model ◽  
Phenotypic Variance ◽  
Multiple Trait ◽  
Environmental Correlations ◽  
Estimation Of Genetic Parameters

AbstractGenetic parameters were estimated for litter size in two prolific sheep breeds, i.e. the Zwartbles and the synthetic breed Swifter. Genetic parameters and breeding values for litter size in different parities were estimated using both a repeatability and a multivariate animal model. The estimated heritability from the repeatability model was 0·10 for the Zwartbles and 0·12 for the Swifter. For the multivariate model, heritability of litter size in first, second and third parity was 0·05, 0·07 and 0·10 for the Zwartbles and 0·09, 0·12 and 0·09 for the Swifter. Genetic correlation for litter size in Swifter was 0·81 between parity 1 and 2 and 0·99 between parity 2 and 3. For the Zwartbles genetic correlations were all very close to unity. Environmental correlations between litter size in subsequent parities were not constant over parities. Phenotypic variance in litter size in both breeds was 0·309 in first parity and was almost 50% higher in later parities. Based on the results it is recommended to apply a multiple trait model.

Genetic analysis of docility score of Australian Angus and Limousin cattle

2018 ◽  
Vol 58 (2) ◽  
pp. 213 ◽  
Author(s):  
S. F. Walkom ◽  
M. G. Jeyaruban ◽  
B. Tier ◽  
D. J. Johnston
Keyword(s):  
Adverse Effect ◽  
Animal Model ◽  
Genetic Analysis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Costs ◽  
Breeding Value ◽  
Maternal Behaviour ◽  
Production Traits ◽  
Subjective Score

The temperament of cattle is believed to affect the profitability of the herd through impacting production costs, meat quality, reproduction, maternal behaviour and the welfare of the animals and their handlers. As part of the national beef cattle genetic evaluation in Australia by BREEDPLAN, 50 935 Angus and 50 930 Limousin calves were scored by seedstock producers for temperament using docility score. Docility score is a subjective score of the animal’s response to being restrained and isolated within a crush, at weaning, and is scored on a scale from 1 to 5 with 1 representing the quiet and 5 the extremely nervous or anxious calves. Genetic parameters for docility score were estimated using a threshold animal model with four thresholds (five categories) from a Bayesian analysis carried out using Gibbs sampling in THRGIBBS1F90 with post-Gibbs analysis in POSTGIBBSF90. The heritability of docility score on the observed scale was 0.21 and 0.39 in Angus and Limousin, respectively. Since the release of the docility breeding value to the Australian Limousin population there has been a favourable trend within the national herd towards more docile cattle. Weak but favourable genetic correlations between docility score and the production traits indicates that docility score is largely independent of these traits and that selection to improve temperament can occur without having an adverse effect on growth, fat, muscle and reproduction.

scholarly journals Animal Model Versus Polynomial Legendre Test-Day In Dairy Cattle

2020 ◽  
Vol 23 (1) ◽  
pp. 5-12
Author(s):  
Mircea Cătălin Rotar ◽  
Horia Grosu ◽  
Mihail Alexandru Gras ◽  
Rodica Ştefania Pelmuş ◽  
Cristina Lazăr ◽  
...  
Keyword(s):  
Animal Model ◽  
Dairy Cattle ◽  
Fixed Effects ◽  
Rank Correlation ◽  
Pedigree Information ◽  
Lactation Period ◽  
Data Set ◽  
Breeding Values ◽  
Normal Limits ◽  
Model Versus

AbstractThe aim of the study was to compare the classical animal model (based on total milk for 305 days) with the Test-Day model (using monthly records of milk yield from Official Records of Performances). The data set derived from a total 175 animals (cows with records, parents of these animals and the descendants) from two Romanian breeds (Romanian Black Spotted and Montbeliarde), the phenotypic and the pedigree information arisen from National Research Development Institute for Animal Biology and Nutrition (IBNA-Balotesti). The selection criteria to be included in the analysis for each cow was to have at least 3 test-days and the days in milk between 200 and 330 for the Test-Day model and the total amount of the 305- day lactation yield for classical Animal Model respectively. Both models use B.L.U.P methodology and for that reason all the estimates were adjusted for fixed effects and all the breeding values and the solution for fixed effects were estimated simultaneous. For the animal model the fixed effects used was the breed and the year of performing and for the Test-Day model was an extra one, the test day effect. The correlation calculated between test days was very high (over 90%) for consecutive tests, and was getting lower when the days between tests was higher (under 40%). Also, in terms of heritability the values were in normal limits throughout lactation, except at the beginning and end of lactation period where these values were a little bit higher. The comparison of the ranking of breeding values with Spearman rank correlation shows that in 80% of the cases the ranking was similar for both models. As the ranking correlations shows, it is certain that the two models are very similar when they are used for genetic evaluation. But, in conclusion, we can say that for a better lactation curve estimation it is recommending to use test-day model for dairy cattle.

scholarly journals PSVIII-38 Late-Breaking Abstract: Estimating genetic parameters of feed efficiency traits in American mink

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 347-347
Author(s):  
Pourya Davoudi ◽  
Duy Ngoc Do ◽  
Guoyu Hu ◽  
Siavash Salek Ardestani ◽  
Younes Miar
Keyword(s):  
Body Weight ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
American Mink ◽  
Genetic Correlations ◽  
Final Body Weight ◽  
Selection For

Abstract Feed cost is the major input cost in the mink industry and thus improvement of feed efficiency through selection for high feed efficient mink is necessary for the mink farmers. The objective of this study was to estimate the heritability, phenotypic and genetic correlations for different feed efficiency measures, including final body weight (FBW), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR) and residual feed intake (RFI). For this purpose, 1,088 American mink from the Canadian Center for Fur Animal Research at Dalhousie Faculty of Agriculture were recorded for daily feed intake and body weight from August 1 to November 14 in 2018 and 2019. The univariate models were used to test the significance of sex, birth year and color as fixed effects, and dam as a random effect. Genetic parameters were estimated via bivariate models using ASReml-R version 4. Estimates of heritabilities (±SE) were 0.41±0.10, 0.37±0.11, 0.33±0.14, 0.24±0.09 and 0.22±0.09 for FBW, DFI, ADG, FCR and RFI, respectively. The genetic correlation (±SE) was moderate to high between FCR and RFI (0.68±0.15) and between FCR and ADG (-0.86±0.06). In addition, RFI had low non-significant (P &gt; 0.05) genetic correlations with ADG (0.04 ± 0.26) and BW (0.16 ± 0.24) but significant (P &lt; 0.05) high genetic correlation with DFI (0.74 ± 0.11) indicating that selection for lower RFI will reduce feed intake without adverse effects on the animal size and growth rate. The results suggested that RFI can be implemented in genetic/genomic selection programs to reduce feed intake in the mink production system.

scholarly journals Estimation of genetic parameters and comparison of random regression animal and sire models of production traits in the first three lactations of Iranian Holsteins

2014 ◽  
Vol 30 (2) ◽  
pp. 261-279 ◽  
Author(s):  
A. Mohammadi ◽  
S. Alijani
Keyword(s):  
Milk Fat ◽  
Genetic Parameters ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Random Regression ◽  
Lactation Period ◽  
Production Traits ◽  
Environmental Variance ◽  
In The Beginning ◽  
Residual Variances

This study was conducted to compare of random regression (RR) animal and sire models for estimation of the genetic parameters for production traits of Iranian Holstein dairy cows. For this purpose, the test day records were used belonged to first three lactations of cows and for, milk, fat and protein yields traits where, collected from 2003 to 2010, by the national breeding center of Iran. The genetic parameters were estimated using restricted maximum likelihood algorithm. To compare the model, different criterion -2logL value, AIC, BIC and RV were used for considered traits. Residual variances were considered homogeneous over the lactation period. Obtained results showed that additive genetic variance was highest in the beginning and end lactation and permanent environmental variance was highest in beginning of lactation than other lactation period. Heritabilities estimate for milk, fat and protein yields by RR animal and sire models were found to be lowest during early lactation (0.05, 0.04 and 0.07; 0.05, 0.19 and 0.13; 0.14, 0.19 and 0.15, for milk, fat and protein yields and in first, second and third lactation respectively). However, estimated heritabilities during lactation did not vary among different order Legendre polynomials, and also between RR animal and sire models. The variation in genetic correlations estimate in the RR animal and sire models was larger in the first lactation than in the second and third lactations. Thus, based on the results obtained, it can be inferred that the RR animal model is better for modeling yield traits in Iranian Holsteins.

Estimates of (co)variances due to direct and maternal effects for body weights in Timahdite sheep

2002 ◽  
Vol 74 (3) ◽  
pp. 409-414 ◽  
Author(s):  
I. Boujenane ◽  
J. Kansari
Keyword(s):  
Animal Model ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Early Growth ◽  
Genetic Effects ◽  
Direct Effects ◽  
Genetic Progress ◽  
Body Weights ◽  
Cross Correlations ◽  
Maternal Heritability

AbstractGenetic parameters for body weights in Timahdite sheep were estimated using records of 10370 lambs from the ‘Société Nationale de Développement de l’Elevage’ born in 1988-89 to 1998-99. An animal model with derivativefree restricted maximum likelihood procedures was used. Random effects were direct and maternal additive genetic, maternal permanent environmental, and error. Direct and maternal heritability estimates were 0·05 and 0·05 for birth weight, 0·02 and 0·07 for weight at 30 days, 0·07 and 0·08 for weight at 70 days, 0·06 and 0·01 for weight at 90 days. Estimates of fraction of variance due to maternal permanent environmental effects were close to zero, except for weight at 90 days. Genetic correlations between direct and maternal genetic effects were –0·55, –0·51, –0·50 and –0·17 for body weights at birth, 30, 70 and 90 days, respectively. Estimates of direct genetic correlations among body weights were positive and high, ranging from 0·69 to unity. Phenotypic correlations were positive and moderate to high, being lower than their corresponding direct genetic correlations. Estimates of correlations between maternal genetic effects among weights were positive and high, varying from 0·79 to unity. Cross-correlations between direct genetic effects for one weight and maternal genetic effects for another weight were consistently negative, ranging from –0·05 to –0·63. These results indicate that selecting for improved maternal and/or direct effects in Timahdite sheep is expected to generate only slow genetic progress in terms of early growth.

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