1. Genetic parameters of test-day milk yield in Guzerá cattle under tropical conditions
- Author
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El Faro L, F. A. T. Bruneli, Maria Gabriela Campolina Diniz Peixoto, Diego Augusto Campos da Cruz, and Annaiza Braga Bignardi
- Subjects
Tropical Climate ,General Medicine ,Heritability ,Biology ,Residual ,Random effects model ,Milk ,Quantitative Trait, Heritable ,Milk yield ,Test day ,Agronomy ,Random regression ,Statistics ,Genetics ,Animals ,Lactation ,Cattle ,Guzera cattle ,Molecular Biology ,Genetic Association Studies ,Selection (genetic algorithm) - Abstract
The objective of this study was to estimate genetic parameters for test-day milk yield (TDMY) in Guzerá cows using random regression models. Additive and permanent environmental random effects were modeled by random regression on fourth- and fifth-order orthogonal Legendre polynomials, respectively. The residual variances were heterogeneous, with seven classes. Heritability estimates for TDMY ranged from 0.24 to 0.52, with higher heritabilities for yields during early lactation. Genetic correlations between TDMYs ranged from -0.03 to 0.95. The phenotypic and permanent environmental correlations were all positive, and the highest estimates were between adjacent TDMYs. The results suggest that TDMYs obtained with random regression models may be used as selection criteria for Guzerá cattle.
- Published
- 2015