Atik Kot Gi̇ysi̇lerden İleri̇ Dönüşüm Yöntemi̇ İle Sanat Eseri̇ Oluşturulmasi: Deni̇z Sağdiç’In Portre Çalişmalarinin İncelenmesi̇ (original) (raw)
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2011
Five models were fitted to weaning weight data of indigenous Tuli cattle to investigate their suitability for evaluation of breeding values. Variance components for direct, maternal, permanent environmental effects, covariance between direct and maternal effects were estimated by restricted maximum likelihood, fitting five different animal models from 4091 pedigree weaning weight records. All investigated models included a random direct effect, but different combinations of random maternal genetic and permanent environmental maternal effects as well as for direct-maternal genetic covariance. The direct heritability ranged from zero to 0.30 when maternal genetic effects were included in model, while direct heritability estimates were 0.21 and 0.68 when maternal effects were excluded. The maternal heritability was higher, 0.26 than direct heritability, zero when only maternal genetic effects were included in the model and were 0.19 and 0.30 when permanent environment maternal effects of the dam was added. The permanent environmental maternal effects were negligible and a small and positive genetic correlation was observed. The proportion of direct additive variance for weaning weight in indigenous Tuli was high which means genetic response might also be high. On the basis of the log likelihood ratio test results and number of parameters used, Model 5 was determined as the most appropriate model for weaning weight of indigenous Tuli cattle of Zimbabwe.
Scientific Journal of Agriculture, 2012
Five models were fitted to weaning weight data of indigenous Nguni cattle to investigate their suitability for evaluation of breeding values. The animal models were ranked using a simple Mallows statistic. Variance components for additive direct, additive maternal, permanent environmental maternal effects, the covariance between additive direct and maternal effects were estimated by restricted maximum likelihood, fitting five animal models from 1278 weaning weight records of indigenous Nguni cattle collected over a period of 10 years (1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999). All investigated models included a random direct effect, but different combinations of random maternal genetic and permanent environmental effects as well as for direct-maternal genetic covariance. The direct heritability (h 2 a ) ranged from 0.0 to 0.25 when the maternal genetic effects were included in the model, while h 2 a estimates were 0.21 and 0.68 when maternal effects were excluded. The maternal heritability (h 2 m ) was lower (0.04) than h 2 a (0.09) when only maternal genetic effects were included in the model, and were 0.13 and 0.17 when the permanent environmental effects of the dam was fitted. The permanent environmental effects of the dam were not important. A large and negative covariance Contents lists available at Sjournals Journal homepage: www.Sjournals.com Original article N. Assan and A. Masache / Scientific Journal of Agricultural (2012) 1(3) 53-60 54
Journal of Animal and Plant Sciences, 2012
Data on368birth records of Swedish Red and White cattle herdraised organically atgan Organic Dairy Cattle Farm for a period of 2006 and 200 9(4years) were used to estimate the effects of different environmental factors on birth weight. Additionally, a comparison of four methods for variance component estimation to compute heritability of birth weight was performed using ML (Maximum likelihood), MINQUE (Minimum variance quadratic unbiased estimation), REML (Restricted maximum likelihood) and Hendersons Method III. Average abortion rate, stillbirth rate, twin and single birth rates of S wedish Red and White cattle were as 4.5%, 4.3%, 3.2% and 87.7% respectively. The least square s mean for birth weight was 37.4±0.70 kg. While effects of calving year (P 0.05). Sire and error variance componentsand standard error of the heritability obtained by using ML method were lower than those obtained by the other three methods. Heritability estimates for birth weight obtained by ML, REML, MINQUE ...
Genetic Parameters Estimation and Trends for Birth Weight in Cattle
J Anim Sci Adv, 2012
In this study data on birth weight (BWT) of local Tuli calves collected from 1988- 1997 at Matopos Research Station, located in Bulawayo, Zimbabwe were analyzed. A single trait animal model was fitted allowing for genetic maternal effects and a genetic covariance between direct and maternal effects. Estimates of heritability for direct genetic effects (h²A), maternal genetic effects (h²M), and the genetic covariance between direct and maternal effects as a proportion of the total variance (cAM) for weaning weight were, 0.25, 0.14, -0.06, respectively. Direct additive genetic variance was twice larger than maternal variance. The correlation between direct and maternal effects was negative implying selection be directed at both components considering the maternal heritability estimate which was moderate. The natures of environmental values suggest that birth weight was not depressed by the tropical harsh semi arid environmental conditions.
2012
Five models were fitted to weaning weight data of indigenous Nguni cattle to investigate their suitability for evaluation of breeding values. The animal models were ranked using a simple Mallows statistic. Variance components for additive direct, additive maternal, permanent environmental maternal effects, the covariance between additive direct and maternal effects were estimated by restricted maximum likelihood, fitting five animal models from 1278 weaning weight records of indigenous Nguni cattle collected over a period of 10 years (1989-1999). All investigated models included a random direct effect, but different combinations of random maternal genetic and permanent environmental effects as well as for direct-maternal genetic covariance. The direct heritability (h 2 a) ranged from 0.0 to 0.25 when the maternal genetic effects were included in the model, while h 2 a estimates were 0.21 and 0.68 when maternal effects were excluded. The maternal heritability (h 2 m) was lower (0.04) than h 2 a (0.09) when only maternal genetic effects were included in the model, and were 0.13 and 0.17 when the permanent environmental effects of the dam was fitted. The permanent environmental effects of the dam were not important. A large and negative covariance Contents lists available at Sjournals
2005
The Tabapuã is a Zebu polled breed used for beef production, with white or gray hair coat and pigmented skin. Weaning (W205, 30,746 observations), twelve-month (W365, 27,701 observations) and 18-month (W550, 18,493 observations) weights of Tabapuã cattle, raised on pastures in several regions of Brazil, from 1975 to 1995, were analyzed with four different single trait animal models (including or not the maternal genetic and/or the permanent environmental effects with the direct genetic effect). Genetic parameters and covariance components were estimated by restricted maximum likelihood method. For all three traits the most complete model that included all three random effects was the best. The model that included only direct genetic effects overestimated the additive genetic variance and heritability (0.27, 0.24 and 0.15 for W205, W365 and W550, respectively). When the permanent environmental effect was included in the model, the portion of the total variance due to it was 0.09, 0.06 and 0.02 for W205, W365 and W550, respectively, and the estimate of the additive genetic variance decreased. The inclusion of the additive maternal effect instead of the permanent environmental effect did not change the estimate of the additive direct variance. Heritability estimates, obtained with the most complete model, were low: 0.16, 0.17 and 0.13 for direct genetic effects, and 0.10, 0.03 and 0.03 for maternal genetic effects, for W205, W365 and W550, respectively. Estimates of genetic correlation between direct and maternal effects were negative, showing an antagonism between such effects. Maternal effects still remained evident after weaning, though they became less important. fax 55-67-5093760 RESUMO. Dados de pesos ao desmame (P205), ao ano (P365) e ao sobreano (P550) de bovinos da raça Tabapuã, criados em regime de pastagens em diversas regiões do Brasil, no período de 1975 a 1995, foram estudados em análise univariadas, sob quatro diferentes modelos de análises (incluindo ou não os efeitos genético materno e de ambiente permanente, além do efeito aditivo direto). Os componentes de (co)variância e parâmetros genéticos foram estimados pelo método da máxima verossimilhança restrita (REML), usando o aplicativo MTDFREML Para as três características, o modelo mais completo forneceu o melhor ajuste dos dados. O modelo que incluiu somente o efeito genético direto do animal superestimou a variância genética aditiva, inflacionando o valor de herdabilidade (0,27, 0,24 e 0,15 para P205, P365 e P550, respectivamente). Quando o efeito de ambiente permanente foi incluído no modelo, a variância genética aditiva decresceu e a porção da variância total em função deste efeito reduziu com o aumento da idade (0,09; 0,06 e 0,02 para P205, P365 e P550, respectivamente). A inclusão do efeito genético materno em vez do efeito de ambiente permanente, praticamente não alterou o valor da variância genética aditiva direta. As estimativas de herdabilidade, obtidas sob o modelo mais completo, foram baixas: 0,16; 0,17 e 0,13 para os efeitos direto e 0,10; 0,03 e 0,03 para os efeitos maternos, para P205, P365 e P550, respectivamente e as estimativas de correlações genéticas entre os efeitos direto e materno foram negativas, evidenciando antagonismo entre estes efeitos. Efeitos maternos permaneceram ainda evidentes após a desmama, porém menos importantes.
Genetic parameter of birth and weaning weights for Friesian calves by using an animal model
Archives Animal Breeding
Birth and weaning weights of 556 Friesian calves by 41 sires out of 318 different dams over a 11 years period were obtained from a herd of Friesian in Sakha Experimental Farm, Ministry of Agriculture, Egypt were used. The records were analyzed by Multiple Trait Likelihood Method (MTDFREML) by using a repeatability animal model (BOLDMAN et al., 1995). Convergence was attained after 699 iterations. The fixed effects included in the model were season and year of calving, parity and sex and the random effects were direct and maternal genetic, permanent maternal environmental and error. Direct heritability estimates for birth weight (BW) and weaning weight (WW) are 0.28 and 0.13, respectively, while, maternal heritability estimates for the same traits are 0.14 and 0.06, respectively. Repeatability estimates are 0.75 and 0.15 for BW and WW, respectively. Phenotypic and genetic correlations are 0.89 and 0.80, respectively. Estimates of calve breeding values ranged from −3.12 to 4.11 ...
South African Journal Of Animal Science
Genetic parameters were estimated for weaning weight (WW) in Kenya Boran cattle using animal models that assumed non-zero direct-maternal genetic covariance. In addition to the direct and maternal genetic effects, maternal permanent environmental and sire by herd-year interaction effects were tested. Two datasets were used. Dataset 1 (DS1) included all animals while dataset 2 (DS2) constituted only records of animals with known paternity. Estimates of direct and maternal heritabilities from DS1 ranged from 0.61 to 0.64 and 0.25 to 0.27, respectively. Estimates of direct and maternal heritabilities from DS2 ranged from 0.07 to 0.31 and 0.16 to 0.23. Direct-maternal genetic correlations were large and negative but were lower in the analyses of DS2 than in DS1. Similarly, estimates of direct and maternal heritability were lower in the analyses of DS2 than in DS1 especially when the effect of sire by herd-year effect was fitted in the model. This study shows that WW is highly heritable ...
Journal of Animal Production Advances, 2013
Maternal effects have been reported using different animal models for post weaning growth traits in some cattle breeds. Variance components for additive direct, additive maternal, permanent environmental maternal effects, the covariance between additive direct and maternal effects were estimated by restricted maximum likelihood, fitting five animal models from 2978 of 18 months (18MW) weight pedigree records of indigenous Tuli cattle of Zimbabwe. All investigated models included a random direct genetic effect, but different combinations of random maternal genetic and permanent environmental effects as well as for directmaternal genetic covariance. The direct heritability (h 2 a) was constant (0.10) when the maternal genetic effects were included in the model, while (h 2 a) estimates were higher (0.22) and (0.63) when maternal effects were excluded. The maternal heritability (h 2 m) was (0.23) and higher than the direct heritability (0.10) when only maternal genetic effects were included in the model and did not change even when the permanent environmental effects of the dam was added. The permanent environmental effect of the dam was negligible and a strong positive correlation between direct and maternal genetic effects (σ 2 am) was observed. The strong positive genetic correlation between direct and maternal genetic effects would not limit the effective utilization of both direct and maternal effects in selection for 18MW growth in indigenous Tuli cattle. A simple animal model with additive direct genetic effects as the only random effect would be appropriate for genetic evaluation of 18MW in indigenous Tuli cattle.