ABSTRACT This study aimed to evaluate genotype × environment (G×E) interactions in Guzerá breed animals for 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), and protein (PY305). We used 6823 records of MY305, 2466 records of FY305, and 1870 records of PY305. The contemporary groups (CG) were created considering herd and year of calving. The analyses were performed in two steps. In the first step, environmental effects on phenotypes were estimated by using a multi-trait model ignoring G×E […]

The objective of this study was to evaluate the genotype-environment interaction (GEI) in the body weight adjusted to 550 days of age (W550) of Polled Nellore cattle raised in Northeastern Brazil using reaction norms (RN) models. Hierarchical RN models included fixed effects for age of cow (linear and quadratic) and random effects for contemporary groups (CG) and additive genetic RN level and slope. Four RN hierarchical models (RNHM) were used. The RNHM2S uses the solutions of contemporary groups estimated by […]

Avaliaram-se modelos estatísticos com diferentes pressuposições para definir o que melhor descreva a presença de interação genótipo × ambiente no ganho de peso pós-desmama ajustado (GPD345) de bovinos Hereford, mediante o estudo de normas de reação ao ambiente, obtidas por regressão aleatória, usando uma abordagem bayesiana. Quatro modelos hierárquicos de normas de reação (MHNR) foram empregados por meio do programa INTERGEN. O MHNRK utiliza as soluções de grupos contemporâneos estimadas previamente pelo modelo animal padrão (MA) e as considera como […]