Medidas morfométricas associadas à predição matemática do peso corporal como ferramenta de manejo em rebanhos de caprinos

Data control is critical to success the production systems. However, goat farming in semi-arid and tropical regions mostly produce artisanal dairy derivatives or handcraft meat products as sausages and salami. Despite the importance, body weight (BW) is frequently unmeasured by small and medium producers due to lack of weighing scales, pen structures and inadequate rural installations. The main objective of this study was to establish equations to estimate BW in Saanen and Anglo Nubian. Data were collected from 125 animals comprising of 65 goats Saanen and 60 goats Anglo-Nubian of different age groups. Measurements were made for withers height, rump height; body length, chest depth, thoracic girth (TG), rump length, rump width (RW), abdominal circumference and BW. For all relationships evaluated between BW (kg) and morphometric measurements (cm), gender effect was significant (P 0.01). The RW presented the highest correlations (R2 = 0.92) with BW of females, while the measurements of TG presented the highest correlations (R2 = 0.92) with BW of males. The following equations were adjusted: BW females = 0.1188 × RW2 + 0.5732 × RW - 5.5888; and BW males = 0.0127 × TG2 – 0.6611 × TG + 11.261. In addition, to estimate BW considering the age in days (t): BW = 36.5674 × exp (-2.2404 exp (-0.0046t)) for males and BW = 27.2616 × exp (-2.4151 exp (-0.00775t)) for females.