Genetic parameters of test-day milk yield in Guzerá cattle under tropical conditions

• DOI: 10.4238/2015.october.28.23
• Publication Date: 2015-11-03T12:00:43Z
• Authors: D.A.C. Cruz; M.G.C.D. Peixoto; F.A.T. Bruneli; A.B. Bignardi; L. El Faro
• Keywords: Genetic correlation; Additive genetic effects; Stepwise regression

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 effects were modeled by on fourth- fifth-order orthogonal Legendre polynomials, respectively. residual variances heterogeneous, with seven classes. Heritability estimates TDMY ranged from 0.24 0.52, higher heritabilities yields during early lactation. Genetic correlations between TDMYs -0.03 0.95. phenotypic all positive, the highest adjacent TDMYs. results suggest that obtained models may be used as selection criteria cattle.