The characterization of genetic resources is an important activity because it provides knowledge for designing appropriate strategies for the use of these and establishes comparisons with other populations. The objective of the present study was to document how the weight of heifers at 15 months of age influences the birth weight and pre-weaning gain of its offspring. During 4 years, a total of 75 Argentine Creole heifers and their offspring were evaluated. Four treatments were performed

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... ng to the 15 month weight of the females as they entered breeding herds: less than 200 kg, 200-230 kg, 231-250 kg and greater than 250 kg. Proc glm of the SAS statistical package was used to evaluate the effect the treatments, year and sex on weight at birth and the pre-weaning average daily gain of the offspring. There were no significant differences in the birth weight of offspring as a function of treatments. The differences were significant when considering year and sex. The male offspring weighed 21.4 kg and the females 19.5 kg (P <0.05). As for the weight gain of calves, there is significant effect of treatments, but not year of birth or sex. The mean pre-weaning weight gain was 0.407 ± 0.107 kg/day. No dystocia problems were observed in the heifers despite the limited body development of some of them. There was a high level of calf losses (18.67 %), possibly related to the low milk capacity of the lighter ones. RESUMEN La caracterización de los recursos genéticos es una actividad importante porque aporta conocimientos que permiten constituir adecuadas estrategias de utilización de los mismos y establecer comparaciones con otras poblaciones. El objetivo del presente trabajo fue conocer en qué medida el peso de la vaquillona de servicio a los 15 meses de edad influye en el peso al nacer y ganancia pre-destete de sus crías. Durante 4 años, un total de 75 vaquillonas Criollo Argentino y sus crías fueron evaluadas. Se conformaron 4 tratamientos en función del peso de ingreso a servicio de las hembras: menores de 200 kg, 200-230 kg, 231-250 kg y mayores de 250 kg. Se utilizó proc glm del paquete estadístico SAS para evaluar el efecto del peso de la vaquillona, año de nacimiento y sexo de la cría sobre el peso al nacer y la ganancia media diaria pre-destete de las crías. No se evidencian diferencias significativas en el peso al nacer de las crías en función de los tratamientos. Las diferencias fueron significativas al considerar año y sexo. Las crías machos