Effect of sire breed and mating density on the reproductive indicators of improved guinea pigs (Cavia porcellus)

Abstract

To evaluate the influence of sire breed and mating density on the reproductive indicators of improved guinea pigs in Chota, Cajamarca, a study was conducted between May 2022 and May 2024. A Completely Randomized Design with a 2×3 factorial arrangement was implemented to evaluate the interaction of two male breeds (Kuri and Peru) with three mating densities (1:6, 1:7, and 1:8) across two consecutive parities. Forty-two females and six males were randomly distributed. Birth weight showed a significant statistical interaction for both male (p = 0.019) and female (p = 0.036) kits. Litter size at birth showed no significant interaction effects (p = 0.664); however, the additive model determined that the sire breed significantly influenced this variable (p = 0.0016). Kuri sires produced an average of 3.45 ± 1.21 offspring/litter compared to 2.52 ± 1.52 offspring/litter obtained with the Peru breed, representing a +37.0% productive advantage, which was confirmed by t-test, Mann-Whitney U test, and Poisson regression. Parity order significantly affected litter size (p = 0.0070), increasing by 0.78 kits during the second cycle, although this induced a consequent reduction in individual birth weight. It is concluded that the sire breed determines the optimal mating density to maximize birth weight and litter size, recommending the use of Kuri sires under 1:6 and 1:8 densities with improved females in the region.