Modelling lactation curves of dairy goats by fitting random regression models using Legendre polynomials or B-splines
| Autor: | Luiz F. Brito, Hinayah R. Oliveira, Felipe Gomes da Silva, Gilberto Romeiro de Oliveira Menezes, Giovani da Costa Caetano, Edson Vinícius Costa, Marcelo Teixeira Rodrigues, Nadson Souza, Ana Lúcia Puerro de Melo, Robledo de Almeida Torres |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Restricted maximum likelihood 0402 animal and dairy science 04 agricultural and veterinary sciences Covariance Heritability Residual 040201 dairy & animal science 03 medical and health sciences 030104 developmental biology Quadratic equation medicine.anatomical_structure Food Animals Random regression Lactation Statistics medicine Animal Science and Zoology Legendre polynomials Mathematics |
| Zdroj: | Canadian Journal of Animal Science. |
| ISSN: | 1918-1825 0008-3984 |
| Popis: | A total of 17 356 test-day milk yield (TDMY) records from 642 first lactations of Alpine goats were used to model variations in lactation curve using random regression models (RRM). Orthogonal Legendre polynomials and B-splines were evaluated to obtain adequate and parsimonious models for the estimation of genetic parameters. The analysis was performed using a single-trait RRM, including the additive genetic, permanent environmental, and residual effects. We estimated the mean trend of milk yield, and the additive genetic and permanent environmental covariance functions through random regression using different orders of orthogonal Legendre polynomial (three to six) and B-spline functions (linear, quadratic, and cubic, with three to six knots). This study further evaluated different number of classes of residual variances. The covariance components and the genetic parameters were estimated using the restricted maximum likelihood method. Heritability estimates presented similar trends for both functions. T... |
| Databáze: | OpenAIRE |
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