Age first gestation dataset
Many studies have focused on comparing the performance of beef heifers and multiparous dams' offspring, but few have explored how the age at first gestation impacts female progeny development and reproductive performance. This research demonstrates that the age at which heifers become pregnant can indeed influence their female progeny's reproductive development. The findings suggest that age at first conception has a notable impact, with adverse effects more pronounced in offspring born to heifers at 15 months. Therefore, selecting replacement heifers born at 27 months is more favorable, as they exhibit larger follicle diameters and better reproductive tract scores at younger ages compared to those born at 15 months. Nevertheless, using heifers born to adult cows remains the most recommended choice due to their greater development and precocity, even compared to those born at 15 or 27 months.
Steps to reproduce
Heifers of 15 and 27 months of age (never previously mated) and multiparous Angus cows were inseminated and conceived to a single Angus sire´s in this study. All female progeny were weighted from birth to slaughter (435d). Ultrasounds and IGF 1 concentration were performed from rearing to slaughter, where the development and weight of the reproductive offspring were evaluated.
Instituto Nacional de Tecnología Agropecuaria