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The Charolais breed has successfully adapted to the Amazonian conditions of Ecuador. The implementation of reproductive and molecular biotechnologies has positioned this breed as the most genetically significant for improvement programs in the region. The objective of this study was to estimate genetic parameters for age at first calving (AFC) under Normal and survival models. Data included animals born between 2010 and 2021, with calving records spanning from 2012 to 2024. The total number of records was 700 after editing. Sire and animal models were considered for the analysis of AFC. The mean AFC was 3.44 years with a standard deviation of 1.19 years. Contemporary group had a significant effect on AFC, but type of cross and multiple ovulation and embryo transfer status had no impact. Under normality assumptions, heritability estimates ranged from 0.17 to 0.21 for sire and animal models, respectively. On the other hand, for the Weibull survival model heritability ranged from 0.45 to 0.74 for sire and animal model, respectively. Estimates for the sire and animal models under Normal assumptions were similar to those reported in literature and thus suggest appropriate model fit. This constitutes an additional step into routine genetic evaluation in Ecuadorian beef cattle.

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Analysis of Age to First Calving in Ecuadorian Charolais Cattle Using Linear and Survival Models

  • 会议论文

  • 发表日期：

    2026年

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  • Luis Favian Cartuche-Macas,
  • Edwin Lozada-Rivadeneira,
  • Pablo Alejandro Quezada-Sarmiento,
  • Napo-león Vargas-Jurado

摘要

The Charolais breed has successfully adapted to the Amazonian conditions of Ecuador. The implementation of reproductive and molecular biotechnologies has positioned this breed as the most genetically significant for improvement programs in the region. The objective of this study was to estimate genetic parameters for age at first calving (AFC) under Normal and survival models. Data included animals born between 2010 and 2021, with calving records spanning from 2012 to 2024. The total number of records was 700 after editing. Sire and animal models were considered for the analysis of AFC. The mean AFC was 3.44 years with a standard deviation of 1.19 years. Contemporary group had a significant effect on AFC, but type of cross and multiple ovulation and embryo transfer status had no impact. Under normality assumptions, heritability estimates ranged from 0.17 to 0.21 for sire and animal models, respectively. On the other hand, for the Weibull survival model heritability ranged from 0.45 to 0.74 for sire and animal model, respectively. Estimates for the sire and animal models under Normal assumptions were similar to those reported in literature and thus suggest appropriate model fit. This constitutes an additional step into routine genetic evaluation in Ecuadorian beef cattle.