Breeding Value Estimation Based on Morphological Evaluation of the Maremmano Horse Population through Factor Analysis

Area of Science:

• Animal Genetics
• Quantitative Genetics
• Animal Breeding

Background:

• Morphological scoring is crucial for evaluating domestic animals like horses.
• The National Association of Maremmano Breeders (ANAM) uses detailed trait data and biometric measurements for horse evaluation.
• Existing evaluation methods may benefit from more integrated approaches.

Purpose of the Study:

• To develop a novel breeding value index for Maremmano horses by integrating morphological traits.
• To apply factor analysis to identify key underlying factors influencing Maremmano horse morphology.
• To assess the practical feasibility and effectiveness of the new index compared to existing methods.

Main Methods:

• Factor analysis was employed on 24 morphological traits and four biometric measurements from 600 Maremmano horses.
• A new breeding index, the New Estimated Breeding Value 1 (NEBV1), was computed using factor scores and ANAM-defined coefficients.
• Spearman correlations were used to compare the rankings of NEBV1 with BLUP-AM-MT and morphological scores.

Main Results:

• Factor analysis identified three primary factors: "Trunk Dimension", "Legs", and "Length".
• The heritability estimates for these factors were 0.51, 0.05, and 0.41, respectively.
• Rotation of the model improved correlations between the NEBV1 and biometric measures, indicating enhanced predictive power.

Conclusions:

• The developed NEBV1 index offers a more comprehensive approach to evaluating Maremmano horses.
• Breeders are encouraged to adopt this factor-derived index for more effective selection of breeding animals.
• This study highlights the utility of factor analysis in refining animal breeding value estimation.