Application of 3D scanning for modeling and morphometric assessment of Mangalarga Marchador Horses.

Overview

• This study assessed the use of portable 3D scanning technology for creating accurate three-dimensional models and measuring body traits of Mangalarga Marchador horses, comparing it to traditional manual measurement methods.

Introduction and Purpose

• Morphometric traits (body measurements) are critical in horse breeding, locomotion analysis, and assessing physical conformation.
• Traditional manual measurements are time-consuming, require direct contact with horses, and may stress the animals.
• There is a need for alternative, non-invasive, and efficient measurement technologies.
• The study’s objective was to evaluate a portable 3D scanner’s effectiveness for modeling and morphometric assessment of Mangalarga Marchador horses.

Methods

• Subjects: 52 adult Mangalarga Marchador horses were involved.
• Measurements: Ten morphometric traits were recorded, including:
  • Withers height (WH)
  • Hip height (HH)
  • Head length (HL)
  • Neck length (NL)
  • Back-loin length (BLL)
  • Croup length (CL)
  • Shoulder length (SL)
  • Body length (BL)
  • Head width (HW)
  • Croup width (CW)
• Techniques:
  • Manual measurements were taken using standard tools.
  • Portable 3D scanning was used to create 3D models and derive measurements.
• Data Analysis:
  • Descriptive analysis summarized the quality of 3D models considering coat color and body region.
  • Pearson correlation was used to analyze associations between manual and 3D-derived measurements.
  • Bland-Altman analysis assessed agreement and bias between methods.
  • The intraclass correlation coefficient (ICC) evaluated reliability and consistency.

Results

• Quality of 3D Models:
  • The torso region had the highest proportion of satisfactory 3D reconstructions.
  • Lower quality models were mainly seen in limbs, head, and neck areas due to their mobility or complexity.
  • Model quality did not significantly vary with the horse’s coat color.
• Comparison of Measurements:
  • Strong correlations (Pearson r > 0.60) between manual and 3D measurements were found for:
    • Withers height
    • Hip height
    • Shoulder length
    • Body length
    • Croup width
  • These traits also showed moderate to good agreement with ICC values ranging from approximately 0.70 to 0.78.
  • Bland-Altman limits of agreement indicated a measurement difference range of –9.94 cm to 5.20 cm for these traits.
  • Traits related to head, neck, and back-loin length exhibited lower correlation and poor agreement (ICC < 0.30), likely due to difficulties capturing mobile or complex anatomical areas with the scanner.

Conclusions and Implications

• Portable 3D scanners are capable of producing accurate 3D models for horse body morphology, particularly for main torso and larger body dimensions.
• 3D scanning provides reliable morphometric measurements that can supplement or partially replace manual measurements, improving efficiency and reducing animal stress.
• The technology is less accurate for morphometric traits in movable or smaller regions such as the head, neck, and back-loin, suggesting these areas may require improved scanning protocols or supplementary methods.
• The consistency across coat colors indicates the scanner’s adaptability to different horse appearances without quality degradation.
• This technology shows promise for non-invasive assessment in equine breeding and management programs.