Association of Temperament with Growth Performance in Nili Ravi Buffalo Heifers

This study investigated the association between temperament and retrospective growth rates in 84 Nili Ravi buffalo heifers aged 18 to 24 months. Temperament was assessed using chute score and exit velocity, measured twice at a seven-day interval, and classified as calm (≤3) or nervous (>3). Retrospective average daily weight gain data were retrieved from farm records, and blood samples were collected to measure cortisol levels. ANOVA was used to analyze data, considering temperament, age group, season, and year of birth as fixed effects, with birth weight as a covariate. Results showed that 48 heifers were calm and 36 were nervous. Calm heifers exhibited significantly higher average daily gains than nervous heifers during the post-weaning period, with an increase of 240 g/day from 4 to 6 months and 190 g/day from 6 to 12 months (p < 0.001). However, this difference was not significant at 18-24 months (p = 0.144). Calm heifers have numerically lower cortisol levels (0.96 vs. 1.27 μg/dL; p = 0.11). These findings suggest that calmer heifers grow faster in early life, emphasizing the importance of temperament in breeding programs aimed at improving growth performance and welfare.