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Cluster analysis of breeding values for milk yield and lactation persistency in Guzerá cattle

2016; UNIVERSIDADE FEDERAL DE SANTA MARIA; Volume: 46; Issue: 7 Linguagem: Inglês

10.1590/0103-8478cr20150418

1678-4596

Diego Augusto Campos da Cruz, Rodrigo Pelicioni Savegnago, Annaíza Braga Bignardi, Maria Gabriela Campolina Diniz Peixoto, F. A. T. Bruneli, Lenira El Faro,

Agricultural and Rural Development Research

ABSTRACT: The aim of this study was to explore the pattern of genetic lactation curves of Guzerá cattle using cluster analysis. Test-day milk yields of 5,274 first-lactation Guzerá cows were recorded in a progeny test. A total of 34,193 monthly records were analyzed with a random regression animal model using Legendre polynomials to fit additive genetic and permanent environmental random effects and mean trends. Hierarchical and non-hierarchical cluster analyses were performed based on the EBVs for monthly test-day milk yield, peak yield, lactation persistency, and partial cumulative and 305-day yields. The heritability estimates for test-day milk yields ranged from 0.24 to 0.52. Cluster analysis identified animals in the population that belong to different groups according to milk production level and lactation persistency.