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Heritability estimates for body weight and height at withers in Brazilian army horses/ Estimativas de herdabilidade para peso corporal e altura de cernelha de equinos do exercito Brasileiro
The aim of this study was to estimate the heritability for weight and height at withers of 260-780 days of age No Defined Breed (NDB) horses, at intervals of 40 days, which belong to the Brazilian Army cavalry. Thus, the model considered the direct genetic effects as random ones, as fixed, the effec...
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Published in: | Ciência rural 2012-12, Vol.42 (12), p.2246-2251 |
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Main Authors: | , , , , |
Format: | Article |
Language: | eng ; spa |
Subjects: | |
Online Access: | Get full text |
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Summary: | The aim of this study was to estimate the heritability for weight and height at withers of 260-780 days of age No Defined Breed (NDB) horses, at intervals of 40 days, which belong to the Brazilian Army cavalry. Thus, the model considered the direct genetic effects as random ones, as fixed, the effects of sex and year of birth and the linear effects of height at withers and age, as covariates for the analysis of body weight, whereas for the analysis of height, the linear effect of weight was included as a covariate. For the complete data, the estimated heritability coefficients were 0.40 [+ or -] 0.034 and 0.70 ± 0.019 for weight and height at withers, respectively, indicating that individual selection for these traits may be effective. On the other hand, for the data subdivided into age classes, the heritability coefficients ranged between 0.04 and 0.77 for weight, with the highest estimation for the class between 440 and 480 days of age, which indicates a higher possibility of weight selection during this period. For height, the heritability values ranged between 0.08 and 0.98, being the highest estimate found between 300 and 340 days of age, corroborating, thus, to the selection of the trait at this age. Key words: cavalry growth traits, selection. Objetivou-se estimar a herdabilidade para peso e altura de cernelha de equinos sem raca definida (SRD), pertencentes a cavalaria do Exercito brasileiro, com idades entre 260 e 780 dias, em intervalos de 40 dias. Assim, o modelo utilizado considerou os efeitos geneticos aditivos diretos como aleatorios, os efeitos de sexo e ano de nascimento como fixos e os efeitos lineares de altura de cernelha e idade do animal, como covariaveis para analise do peso corporal, sendo que, para analise da altura, o efeito linear do peso foi incluido como covariavel. Para o arquivo completo, os coeficientes de herdabilidade estimados foram 0,40 ± 0,034 e 0,70 [+ or -] 0,019, para peso e altura de cernelha, respectivamente, indicando que a selecao individual para essas caracteristicas pode ser eficiente. Entretanto, para os arquivos subdivididos em classes de idade, os coeficientes de herdabilidade variam entre 0,04 e 0,77 para peso, sendo a maior estimativa obtida para a classe entre 440 e 480 dias de idade, o que indica maior possibilidade de selecao para peso nesse periodo. Para altura, as herdabilidades oscilaram entre 0, 08 e 0, 98, sendo a maior estimativa encontrada entre 300 e 340 dias de idade, corroborando a selecao da c |
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ISSN: | 0103-8478 1678-4596 |