Principal component and canonical correlation analyses of morphometric and physiological traits in Bali cattle

Bali cattle (B. javanicus domesticus) adapts to tropical heat stress. This study evaluated multivariate associations between morphometric and physiological traits in 95 females aged 2–7 years. Morphometric included withers height (WH), body length (BL), chest girth (CG), chest depth (CD), hip height (HH), hip width (HW) and body weight (BW). Physiological traits comprises respiration rate (RR), heart rate (HR), rectal temperature (RCT) and body surface temperatures at the eye (ES), forehead (FH), dorsal (DS) and hip (HS). Analyses included descriptive statistics, Pearson correlation, principal component analysis (PCA) and canonical correlation analysis (CCA). Cattle age 6–7 years exhibited greater BW and BL than age 2–3 years (p < 0.05), whereas FH and HR were lower in 6–7 years, while RCT remained stable across age groups. Correlations between morphometric and physiological traits were weak (r = –0.362 to 0.144). PCA showed that morphometric variation was mainly explained by PC1, dominated by BW, CG and BL (67.30%), whereas physiological variation was associated with body surface temperatures (34.56%). Canonical correlation analysis revealed moderate significant relationship (r = 0.563; Pr > F = 0.0074). Larger body dimensions were associated with lower thermal response indicators, reflecting thermal inertia and heat exchange efficiency.