Genotype-environment interaction for age at first calving in buffaloes, using the reaction norm model

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Livestock Science

Background:

• Age at first calving is a key reproductive trait in buffaloes, influencing herd productivity.
• Understanding genotype-environment interaction (GxE) is vital for effective genetic selection in diverse farming systems.

Purpose of the Study:

• To evaluate the genotype-environment interaction (GxE) effect on age at first calving in buffaloes.
• To compare the standard animal model with the reaction norm model for GxE analysis.

Main Methods:

• Analysis of buffalo reproductive records using a standard animal model.
• Application of a reaction norm model with environmental gradients based on age at first calving and milk yield averages.
• Estimation of heritability and genetic correlations under different environmental conditions.

Main Results:

• Heritability estimates for age at first calving differed between the standard animal model and the reaction norm model.
• The reaction norm model demonstrated high heritability in favorable environments.
• Low genetic correlations were observed between extreme environments, indicating specific adaptation.

Conclusions:

• Genotype-environment interaction plays a significant role in determining age at first calving in buffaloes.
• The reaction norm model provides a more nuanced understanding of GxE effects compared to the standard animal model.
• These findings have implications for optimizing breeding strategies in buffaloes across varying environments.