Advances in horse morphometric measurements using LiDAR

Abstract

Zoometric measurements have a potential value in differentialing between individuals and within populations. The measurement of body size in horses and livestock plays a significant role in functional longevity, production, and reproductive performance and health. In this context, the measurements obtained without contact by detection systems and visualized by computers could represent a great advance over conventional measurements that are tedious, time consuming and stressful for the animals. This study presents a new approach to taking zoometric measurements of an animal's body based on digital three-dimensional modelling. The capture of the data series was carried out by a LiDAR sensor. The 16 laser beams of the sensor were able to fully scan a horse, performing a 3D reconstruction of the horse's side, through which body measurements were obtained. Five Pura Raza Española horses (PRE) (3 stallions and 2 mares) with ages ranging between 5 and 18 years old were scanned. The PRE is the most recognized native Spanish horse population for its census (national and international), cultural and socioeconomic importance. For each horse, 17 zoometric measurements (linear and angular) were taken both manually and using the LiDAR-based system to check the usefullness of this non-invasive technology in obtaining quick livestock measurements while causing minimal stress to the animals. Of the 17 zoometric measurements obtained manually and with the sensor, 10 (58.82%) had a mean relative error that ranged between > 0 and < 10; 5 (29.41%) had an error that ranged ≥ 10 and < 20; and two (As and ACr) had an error ≥ 20 (11.76%). A total of 82.5% of the traits studied had an accuracy (v2) lower than 5%. Therefore, although this approach could still be improved, it verifies the viability of noncontact measurements of large livestock.