Phenotypic diversity and morphometric patterns of Creole goats in the Peruvian Amazonian: a multivariate approach

Abstract

Background and Aim: Creole goats (Capra hircus) constitute an important genetic resource in tropical production systems; however, their morphostructural characterization in the Peruvian Amazonian remains limited. This study aimed to evaluate the morphological and morphometric characteristics, body indices, and multivariate structure of Creole goats to identify patterns of phenotypic variability and functional adaptation under extensive systems. Materials and Methods: A total of 149 adult Creole goats were evaluated across three districts (Bagua Grande, Cumba, and El Milagro). 15 qualitative traits and 31 morphometric variables were recorded using standardized protocols. Six ethnological indices; body index (BI), cephalic index (CI), facial index (FI), thoracic index (TI), pelvic index (PI), and proportionality index (PrI), and nine productive indices; thoracic metacarpus index (TMI), costal metacarpus index (CMI), posterior podal index, relative thoracic depth index (RTDI), transverse pelvic index, longitudinal pelvic index, compactness index (CoI), relative cane thickness index, and cane load index, were calculated. Statistical analyses included descriptive statistics, Fisher’s exact test, Z-test, Mann–Whitney U test, Student’s t-test, and Welch’s t-test. Relationships among indices were assessed using Pearson’s correlation coefficient, and multivariate structure was explored using principal component analysis (PCA). Results: Significant sexual dimorphism was observed, with males showing higher body weight, greater skeletal robustness, and higher FI, TMI, and CoI, whereas females exhibited higher TI and distinct mammary traits. Ecotype differentiation revealed that longilinear goats had elongated conformations with lower PrI values, while brevilinear goats exhibited compact and robust structures with higher TMI, CMI, and cane load index values. Strong correlations were identified between BI and FI, as well as among productive indices such as TMI, RTDI, and CoI (p ≤ 0.001). PCA explained 57.4% of total variability, with body weight and thoracic-related measurements contributing most to the first component, confirming their importance in morphostructural differentiation. Conclusion: Creole goats in the Peruvian Amazonian exhibit high phenotypic variability and clear morphostructural differentiation influenced by sex, ecotype, and environment. Body measurements and indices provide reliable tools for field-based selection and characterization. The integration of morphometric and multivariate approaches offers a robust framework for genetic improvement, conservation, and sustainable management of goat populations in tropical production systems.