scholarly journals GENETIC PARAMETERS OF GIROLANDO CROSSBRED COWS IN DAIRY HERDS IN THE STATE OF ACRE, BRAZIL

2020 ◽  
Vol 23 (1cont) ◽  
Author(s):  
Andressa Pereira Braga ◽  
José Marques Carneiro Júnior ◽  
Antônia Kaylyanne Pinheiro ◽  
Maurício Santos Silva
Keyword(s):  
Maximum Likelihood ◽  
Milk Production ◽  
Genetic Parameters ◽  
Heritability Estimate ◽  
Restricted Maximum Likelihood ◽  
Dairy Herds ◽  
Genetic Progress ◽  
Linear Unbiased Prediction ◽  
Best Linear Unbiased ◽  
Selection For

This study aimed at estimating genetic parameters for milk production and conformation characteristics in Girolando crossbred dairy cows reared in the High and Low Acre region using the restricted maximum likelihood methodology, under an animal model. We estimated the variance components and genetic parameters using the REML/BLUP procedure (Restricted Maximum Likelihood Methodology/Best Linear Unbiased Prediction). The estimated average for milk production for 305 days of lactation (P305) was of 1523.25 ± 481.11 kg, with a heritability of 0.38 for this characteristic. The conformation characteristics showed no significant correlation with milk production. The phenotypical correlations between the linear characteristics of type were, in general, positive and moderate. The P305 obtained in this study can be considered low and indicates that there is a possibility of increasing milk production through selection in herds along with the use of tested and proven bulls. The heritability estimate found (0.38) indicates that there is genetic variability for milk production, demonstrating that selection for this characteristic would result in genetic progress.

scholarly journals Parentesco na seleção para produtividade e teores de óleo e proteína em soja via modelos mistos

2013 ◽  
Vol 48 (9) ◽  
pp. 1246-1253 ◽  
Author(s):  
Larissa Correia de Melo Pinheiro ◽  
Pedro Ivo Vieira Good God ◽  
Vinícius Ribeiro Faria ◽  
Ane Gabrielle Oliveira ◽  
Aline Akemi Hasui ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Best Linear Unbiased Prediction ◽  
Restricted Maximum Likelihood ◽  
Linear Unbiased Prediction ◽  
Best Linear Unbiased ◽  
Unbiased Prediction

O objetivo deste trabalho foi avaliar influência da informação de parentesco na seleção de progênies de soja quanto à produtividade e aos teores de óleo e proteína, com base no uso de modelos mistos de predição dos valores genéticos. Novecentas progênies F4:6 e 200 progênies F4:7 de soja foram avaliadas nas safras 2010/2011 e 2011/2012, respectivamente. As progênies foram obtidas de cruzamentos múltiplos a partir de 57 progenitores. Os dados foram analisados por meio de modelos aleatórios (quadrados mínimos) e mistos BLUP/REML ("best linear unbiased prediction/restricted maximum likelihood"). Os maiores valores de ganhos preditos foram obtidos com o BLUP/REML. Os valores genéticos preditos com o método BLUP/REML, sem informação de parentesco, apresentaram alta correlação com aqueles obtidos com o modelo aleatório, além de detectada alta coincidência das progênies selecionadas. A inclusão da matriz de parentesco resultou na seleção de progênies diferentes e em maior acurácia na predição dos valores genéticos.

scholarly journals Estimação de parâmetros genéticos e predição de valor genético aditivo de trigo utilizando modelos mistos

2014 ◽  
Vol 49 (11) ◽  
pp. 882-890 ◽  
Author(s):  
Adérico Júnior Badaró Pimentel ◽  
João Filipi Rodrigues Guimarães ◽  
Moacil Alves de Souza ◽  
Marcos Deon Vilela de Resende ◽  
Lisandra Magna Moura ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Best Linear Unbiased Prediction ◽  
Restricted Maximum Likelihood ◽  
Linear Unbiased Prediction ◽  
Best Linear Unbiased ◽  
Unbiased Prediction

O objetivo deste trabalho foi estimar os parâmetros genéticos e predizer o valor genético de populações e indivíduos oriundos de populações segregantes de trigo, com o uso da metodologia de modelos mistos ("restricted maximum likelihood"/"best linear unbiased prediction", REML/BLUP). Trinta e seis populações segregantes de trigo e quatro controles foram avaliados na geração F3, em delineamento de blocos ao acaso, com informações de indivíduo retiradas de dentro das parcelas. Os caracteres avaliados foram: produção de grãos, índice de colheita, número de perfilhos e altura de planta. Observou-se a existência de variabilidade genética entre populações em todos os caracteres avaliados. A herdabilidade média variou de 39,15 a 92,78%, e a acurácia, de 62,57 a 96,32%, na seleção de populações. A herdabilidade individual no sentido restrito foi baixa dentro das populações, em todos os caracteres. A acurácia na seleção individual apresentou magnitude média, quanto ao caráter altura de plantas, e baixa quanto aos demais caracteres. A herdabilidade individual contribui para maior ganho nos caracteres altura de planta e índice de colheita com o uso do BLUP individual, em comparação ao BLUP de populações. As populações segregantes Embrapa22/BRS207, Embrapa22/VI98053, Embrapa22/IVI01041, BRS254/BRS207, BRS254/VI98053, BRS254/UFVT1Pioneiro e BRS264/BRS207 destacam-se por apresentar valor genético aditivo elevado em dois ou mais caracteres.

Selection on lean growth in a nucleus of Landrace pigs: an analysis using Gibbs sampling

1996 ◽  
Vol 63 (2) ◽  
pp. 243-253 ◽  
Author(s):  
M. C. Rodriguez ◽  
M. Toro ◽  
L. Silió
Keyword(s):  
Gibbs Sampling ◽  
Variance Components ◽  
Fixed Effects ◽  
Prediction Method ◽  
Environmental Parameters ◽  
Linear Unbiased Prediction ◽  
Normal Distributions ◽  
Lean Growth ◽  
Best Linear Unbiased ◽  
Selection For

AbstractData from 4150 Landrace pigs tested during the period 1989-94 for backfat thickness and age at 100 kg in an open selection nucleus were analysed with the standard restricted maximum likelihood/best linear unbiased prediction method and with a Bayesian approach based on the marginal posterior distributions of parameters of interest achieved via Gibbs sampling. Breeding values and fixed effects were sampled from normal distributions and (co)variance components from inverted Wishart distributions. The Bayesian analysis indicated that the selection was effective for both traits. Assuming flat priors for the (co)variance components, the posterior means of the annual rates of response to selection for both traits were −0·473 days and −0·212 mm. The influence of informative priors constructed from (co)variances estimated in the French Landrace breed on inferences about genetic and common environmental parameters, genetic group effects and total and annual responses was also examined.

Preliminary genetic analyses of voluntarily supplied disease data in Australian dairy herds

2010 ◽  
Vol 50 (3) ◽  
pp. 186 ◽  
Author(s):  
M. Haile-Mariam ◽  
M. E. Goddard
Keyword(s):  
Genetic Parameters ◽  
Dairy Herd ◽  
Dairy Herds ◽  
Event Data ◽  
Economic Traits ◽  
Health Event ◽  
Health Disorders ◽  
Selection For ◽  
Improvement Scheme ◽  
Environmental Measures

Health disorders data collected from Australian dairy herds were analysed to estimate incidence levels and genetic parameters for some diseases traits and to examine the consequence of selection for Australian profit ranking (the economic index in Australia) and other economic traits on incidence of some diseases. Data on disease problems including udder, leg, reproductive and ‘all disorders’ were extracted from the Australian Dairy Herd Improvement Scheme database for cows that calved in 2007 and 2008 and were analysed fitting a linear sire model. The occurrence of disease problems was as high as 0.3 if ‘all disorders’ were put into one group. Five percent of the cows that calved showed leg problems and the incidence of udder problems was ~0.13. The heritability of all disease problems ranged from 0.01 for reproductive problems to 0.03 for udder problems. The results showed that selection on milk yield traits will likely increase the frequency of all health disorders. Although selection on udder depth and somatic cell count helps to mitigate the possible genetic deterioration in udder problems, it is unlikely to avoid it totally. Therefore, more effort to collect and analyse health event data from Australia dairy herds could help to better design genetic and environmental measures to reduce the consequence of health problems.

scholarly journals Genetic evaluation and selection correlated response of growth traits in Japanese quail

2020 ◽  
Vol 50 (2) ◽  
pp. 325-333
Author(s):  
M.M. El-Attrouny ◽  
E.A. Manaa ◽  
S.I. Ramadan
Keyword(s):  
Growth Traits ◽  
Best Linear Unbiased Prediction ◽  
Correlated Response ◽  
Genetic Trend ◽  
Linear Unbiased Prediction ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Best Linear Unbiased ◽  
Selection For ◽  
Genetic Trends

Objectives of the current study were to i) investigate effects of selection for bodyweight at four weeks old on bodyweight (BW) and bodyweight gain (BWG) across four generations; ii) estimate correlated response to selection for BW and BWG at different ages; and iii) document best linear unbiased prediction (BLUP) of genetic trends for BW and BWG across four generations of selection. A total of 3540 chicks from 444 sires and 885 dams were used to estimate heritabilities, and genetic and phenotypic correlations for growth traits, including BW at 0, 2, 4, and 6 weeks, and BWG between 0 and 2, 2 and 4, 4 and 6, and 0 and 6 weeks. The selection effects, correlated responses and genetic trend for BW and BWG across generations were quantified by applying the animal model. Estimates of heritability for BW and BWG ranged from 0.22 to 0.42 and from 0.18 to 0.23, respectively. Ranges of genetic and phenotypic correlations for BW varied from 0.31 to 0.92 and 0.05 to 0.65, respectively. Moreover, estimates of genetic and phenotypic correlations for BWG at different ages were from 0.12 to 0.72 and 0.17 to 0.60, respectively. Bodyweight and BWG estimates after four generations of selection were significantly higher than those of the base generation. Moreover, contrasts of generation means were significant across the four generations. The genetic trends across the generations clarified that BLUP estimates for BW and BWG gradually increased with the advance of generations until the fourth generation. Keywords: best linear unbiased prediction, bodyweight, heritability, selection, genetic trend

Genetic evaluation of pedigree beef cattle in Great Britain

1993 ◽  
Vol 1993 ◽  
pp. 106-106
Author(s):  
R E Crump ◽  
J G E Bryan ◽  
D Nicholson ◽  
R Thompson ◽  
G Simm
Keyword(s):  
Great Britain ◽  
Herd Size ◽  
Best Linear Unbiased Prediction ◽  
Individual Animal ◽  
Genetic Progress ◽  
Linear Unbiased Prediction ◽  
Beef Herds ◽  
Best Linear Unbiased ◽  
Improved Performance ◽  
High Level

In order that genetic progress in British beef breeds could be improved, performance traits have been recorded by the Meat and Livestock Commission for many years. A large number of pedigree beef herds have recorded with the Meat and Livestock Commission during this period. Until recently, these records were only made use of via within herd contemporary comparisons such that the results for animals could not be compared across herds or time.Through the use of Individual Animal Model Best Linear Unbiased Prediction (BLUP), differences between herds and contemporary groups within herds can be accounted for provided there are genetic links between herds and contemporary groups. As a result of the small pedigree herd size in Great Britain, typically less than 20, sires are often chosen from outside the herd in order to reduce inbreeding. This practise has resulted in there being a relatively high level of connectedness between contemporary groups and this enables the BLUP procedure to disentangle management and genetic effects.

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