Evolution of carcass traits, pH, color and non-carcass components of guinea pigs from three to six months of age.

Guinea pig (Cavia porcellus) production represents an important source of high-quality animal protein in Andean regions, however knowledge regarding the evolution of carcass characteristics and meat quality parameters during the growth period is limited. This study investigated the progression of carcass traits, regional composition, linear measurements, pH and color evolution during muscle-to meat conversion, and non-carcass components in Peru breed guinea pigs at three critical ages: 3, 4, and 6 months. A total of 120 animals (20 males and 20 females per age group) were evaluated following standardized slaughter and carcass evaluation protocols. Results demonstrated significant age-dependent increases in live weight at slaughter, empty body weight, and hot and cold carcass weights. Males exhibited higher values than females across all weight parameters. Regional composition analysis revealed proportional changes in shoulder and neck (in females) and long leg and ribs (in males) percentages with advancing age. Linear measurements showed progressive increases in all carcass dimensions, with carcass compactness indices improving significantly from 3 to 6 months. Post-mortem pH evolution in Longissimus thoracis and Psoas major muscles followed expected glycolytic patterns. Color parameters exhibited distinct temporal and age-related variations, with younger animals showing more pronounced changes during the muscle-to-meat conversion process. Non-carcass components evaluation demonstrated allometric growth patterns relative to body size, with peri-renal fat deposition increasing substantially between 3 and 6 months. These findings provide essential baseline results for optimizing slaughter age decisions and understanding meat quality development in guinea pig production systems, contributing to the standardization of carcass evaluation protocols for this emerging livestock species.