Preliminary Results on the Zoometric Characterization and Dimorphism of Creole Horses in Two Cantons of Manabí

Little effort has been made so far on morphometry and conservation studies in horses of the creole biotype in Ecuador due to preferences toward other breeds or crossbreeds. This research aims to analyze zoometric measures and indexes and the manifestations of sexual dimorphism in Ecuadorian Creole horses. One hundred and one animals were evaluated in 24 de Mayo (29 mares and 81 horses) and 118 in Pichincha (47 mares and 71 horses) in Manabí, all aged over 5 years. Zoometric variables were measured, such as head length and head width; height at the withers and croup; diameters: longitudinal, dorsum-sternal, and bicoastal; width and length of the crou; thoracic and cane perimeters. The measurements presented variations between 3.55% and 10.15% and a highly significant difference (p < 0.01) except for the length of the rump (p = 0.025) and longitudinal diameter (p = 0.102). Zoometric indexes such as cephalic, body, thoracic, the relative depth of the thorax, metacarpop-thoracic, and pelvic were evaluated, and proportionality variations between 2.41% and 8.92% were observed. They presented highly significant differences (p < 0.01) except for the indexes depth relative to chest (p = 0.202) and proportionality (p = 0.014). No sexual dimorphism was observed in general except for the head and body indexes on 24 de Mayo. The zoometric categorization of the animals cannot be concluded due to the marked variation of the data for each sex within and between the cantons due to the existence of high morphometric heterogeneity between them, for which it is necessary to develop selection and cross-breeding criteria. Keywords: local breeds, equine, morphometrics, linear measurements. Resumen Se ha realizado poco esfuerzo hasta el momento sobre estudios de morfometría y conservación en caballos de biotipo criollo en Ecuador por preferencias hacia otras razas o mestizajes. El objetivo de esta investigación fue analizar medidas e índices zoométricos y manifestación de dimorfismo sexual en caballos criollos ecuatorianos. Fueron evaluados 110 animales en 24 de Mayo (29 yeguas y 81 caballos) y 118 en Pichincha (47 yeguas y 71 caballos) en Manabí, todos con edades mayor a 5 años. Se midieron variables zoométricas: longitud de cabeza y ancho de cabeza, alzadas a la cruz y grupa, diámetros longitudinal, dorso esternal y bicostal, ancho y largo de grupa, perímetros torácico y de caña; la medidas presentaron variaciones entre 3.55% y 10.15% y diferencia altamente significativa (p