Patrón dinámico de crecimiento de gazapos de chinchilla (<i>Chinchilla lanigera</i>) durante la lactancia

Abstract

The ability of linear and exponential functions to describe the dynamic behavior of body weight of chinchilla kits during lactation was evaluated. Residual variance and coefficient of determination average values derived from each model assigned to linear function a slight advantage. While the linear function underestimated birth weight the exponential model overestimated it showing both models differences of similar magnitude between estimated and observed values. The use of the linear model to characterize the dynamic growth of male kits belonging to litters with one, two or three pups, between birth and weaning at 43 days of age, allowed to confirm that increasing litter size from one to two pups slightly decreases their initial body weight and their growth rate during lactation, without a detrimental effect on overall pre-weaning growth. By contrast, the presence of a third kit in the litter markedly reduces both initial body weight and daily body weight gain from birth to weaning. According to data surveyed in this study increasing the number of parturitions per female per year, for example through an appropriate management of photoperiod, would be more useful than increasing litter size at birth above two kits to increase the overall efficiency of the system.