da Silva, A., Dalto, D., Lozano, A., de Oliveira, E., Gavioli, D., de Oliveira, J., Jamile, Romero, N. and da Silva, C. 2013. Differences in muscle characteristics of piglets related to the sow parity. Can. J. Anim. Sci. 93: 471-475. Two hundred forty-three piglets were obtained from 81, 1st through 7th parity sows to determine the influence of sow's parity on piglets′ myogenesis. Those piglets weighing close to or equal to the average weight of their litter were sacrificed, and their semitendinosus muscles were collected to determine the secondary muscle fiber number, area and weight. The number of secondary muscle fibers was correlated with muscle weight (P<0.05; 0.39) and muscle area (P<0.001; 0.63), and muscle area and weight were also correlated (P<0.001; 0.64). Weights of piglets at birth had a correlation with number of muscle fibers (P<0.05; 0.39), muscle area (P<0.001; 0.54) and muscle weight (P<0.001; 0.73). The piglets′ birthweights and muscle weight, muscle area and muscle secondary fiber numbers increased quadratically as parity increased (R²=0.56, 0.36, 0.44, 0.64 and 0.54; P<0.05, respectively). The results of this study indicate that parity influences the pre-natal development of piglets and that the best muscle characteristics of piglets born from 3rd and 4th parity sows were responsible for their higher weight at birth.