Avaliação de medidas da persistência da lactação de cabras da raça Saanen sob modelo de regressão aleatória

Menezes, G. R. de O.; Torres, Robledo de Almeida; Sarmento, José Lindenberg Rocha; Rodrigues, Marcelo Teixeira; Melo, Ana Lúcia Puerro de; Silva, Felipe Gomes da; Brito, Luiz F.

doi:10.1590/s1516-35982010000800010

Cited by 6 publications

(4 citation statements)

References 14 publications

(15 reference statements)

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“…Conversely, additive genetic variance was small up to the turning point of the lactation curve. These results are in agreement with those from Menezes et al (2008b), who evaluated different lactation measures of persistence for Saanen goats using RRMs. They found low heritability for all of the evaluated measures.…”

Section: Resultssupporting

confidence: 91%

Random regression models using Legendre orthogonal polynomials to evaluate the milk production of Alpine goats

Silva

Torres²,

Brito³

et al. 2013

Genet. Mol. Res.

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ABSTRACT. The objective of this study was to identify the best random regression model using Legendre orthogonal polynomials to evaluate Alpine goats genetically and to estimate the parameters for test day milk yield. On the test day, we analyzed 20,710 records of milk yield of 667 goats from the Goat Sector of the Universidade Federal de Viçosa. The evaluated models had combinations of distinct fitting orders for polynomials (2-5), random genetic (1-7), and permanent environmental (1-7) fixed curves and a number of classes for residual variance (2, 4, 5, and 6). WOMBAT software was used for all genetic analyses. A random regression model using the best Legendre orthogonal polynomial for genetic evaluation of milk yield on the test day of Alpine goats considered a fixed curve of order 4, curve of genetic additive effects of order 2, curve of permanent environmental effects of order 7, and a minimum of 5 classes of residual variance because it was the most economical model among those that were equivalent to the complete model by the likelihood ratio test. Phenotypic variance and heritability were higher at the end of the lactation period, indicating that the length RR using LOP to evaluate milk production of Alpine goats of lactation has more genetic components in relation to the production peak and persistence. It is very important that the evaluation utilizes the best combination of fixed, genetic additive and permanent environmental regressions, and number of classes of heterogeneous residual variance for genetic evaluation using random regression models, thereby enhancing the precision and accuracy of the estimates of parameters and prediction of genetic values.

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Section: Resultssupporting

confidence: 91%

Random regression models using Legendre orthogonal polynomials to evaluate the milk production of Alpine goats

Silva

Torres²,

Brito³

et al. 2013

Genet. Mol. Res.

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“…Collection of milk samples were done monthly and sent to Milk Quality Lab for quantification of contents of fat, protein, lactose and total dry extract. Menezes et al (2010), studying lactation persistence measures of Saanen goats under random regression model, suggested using some adaptations of the measures found in the literature on dairy bovines, as for the example, the use of 268 days of lactation length, (9 months), rather than 305 days. In this paper the total milk production was estimated until 270 days of lactation.…”

Section: Methodsmentioning

confidence: 99%

Genetic and environmental factors that influence production and quality of milk of Alpine and Saanen goats

Brito

Silva²,

Melo³

et al. 2011

Genet. Mol. Res.

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ABSTRACT. Data from 1279 lactations of 783 Alpine and Saanen goats of the herd of our university in Minas Gerais, Brazil, were used to study environmental effects on and to estimate genetic parameters for milk production until 270 days of lactation (MP270) and for production and percentages of fat (PFAT and %FAT), protein (PPROT and %PROT), lactose (PLACT and %LACT), and total dry extract (PEXTR and %EXTR). Environmental effects were estimated by a statistical model that included contemporary group effect, type of kidding, genetic grouping, and kidding order. A multi-trait animal model with animal and permanent environment random effects was used to estimate genetic parameters and the significant environmental effects (fixed). Contemporary group influenced all traits; genetic grouping did not influence %LACT; type of kidding did not influence PFAT, %PROT or %LACT, and kidding order did not influence %FAT or %EXTR. Estimates of genetic correlations among MP270 and production of milk constituents were positive and high, but correlations between MP270 and %FAT, MP270 and %PROT, MP270 and %ESTR were moderate and negative. These heritability estimates show that satisfactory genetic gains can be obtained by selection, especially for milk constituents.

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“…O sucesso dos sistemas de produção animal é mundialmente dependente do grau de eficiência econômico produtiva que se atinge, sendo importante salientar que essa eficiência não significa, propriamente, máxima produtividade. A cadeia produtiva de ovinos não é diferente e, portanto, precisa estar alinhada a essa tendência mundial (Menezes et al, 2010).…”

Section: Introductionunclassified

Influência do período do ano e horário do dia sobre os parâmetros fisiológicos de ovelhas Santa Inês na microrregião do Alto Médio Gurguéia

Silva¹,

Silva²,

Rocha³

et al. 2013

Pubvet

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Vários fatores influenciam a produção animal, dentre eles os sistemas de produção e fatores climáticos podem provocar alterações fisiológicas e interferir na produtividade. Sendo assim, os autores objetivaram avaliar a influência do período do ano e horário do dia sobre os parâmetros fisiológicos de ovelhas Santa Inês na microrregião do Alto Médio Gurguéia. Foram utilizadas oito matrizes da raça Santa Inês distribuídas em um delineamento inteiramente casualizado em esquema fatorial 4x2, quatro períodos do dia, 7-8, 10-11, 14-15 e 17-18 h, e dois períodos: PC 1 (quente e seco), outubro a SILVA, A.S. et al. Influência do período do ano e horário do dia sobre os parâmetros fisiológicos de ovelhas Santa Inês na microrregião do Alto Médio Gurguéia. PUBVET,

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Avaliação de medidas da persistência da lactação de cabras da raça Saanen sob modelo de regressão aleatória

Cited by 6 publications

References 14 publications

Random regression models using Legendre orthogonal polynomials to evaluate the milk production of Alpine goats

Random regression models using Legendre orthogonal polynomials to evaluate the milk production of Alpine goats

Genetic and environmental factors that influence production and quality of milk of Alpine and Saanen goats

Influência do período do ano e horário do dia sobre os parâmetros fisiológicos de ovelhas Santa Inês na microrregião do Alto Médio Gurguéia

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