Genetic associations of temperament and facial hair whorls with productive, reproductive, and carcass traits in Canchim beef cattle

Objective: This study aimed to estimate genetic parameters and evaluate genetic correlations between temperament and facial hair whorl traits with productive, reproductive, and carcass traits in Canchim beef cattle. Methods: Phenotypic records from animals born between 2013 and 2022 were analyzed. Temperament was assessed using behavioral scores (movement, tension, breathing, vocalization), reactivity measured by accelerometers, and flight time, while facial hair whorls were characterized by presence, number, position, and height. Productive, reproductive, and carcass traits included body weights, scrotal circumference, and ribeye area at different ages. Genetic parameters were estimated using single- and two-trait animal models. Results: Heritability estimates ranged from low to high (0.09 to 0.67), indicating sufficient additive genetic variability for all trait groups. Favorable genetic correlations were observed between body weight traits and temperament measures, particularly vocalization and flight time, as well as between ribeye area and reactivity flight time. Scrotal circumference at 12 and 18 months of age showed moderate to high genetic correlations with facial hair whorl traits, especially whorl number and position. Conclusion: These results indicate that selection for productive and reproductive traits can lead to indirect improvements in temperament. Moreover, pre-selection for the absence of facial hair whorls, combined with selection for body weight and scrotal circumference, may promote favorable genetic gains in temperament, supporting their inclusion in Canchim breeding programs.