Revista Brasileira de Zootecnia Full-length research article Brazilian Journal of Animal Science © 2018 Sociedade Brasileira de Zootecnia ISSN 1806-9290 R. Bras. Zootec., 47:e20180013, 2018 https://doi.org/10.1590/rbz4720180013 www.sbz.org.br Non-ruminants Association of morphometric measurements with morphologic scores of Criollo horses at Freio de Ouro: a path analysis Anelise Maria Hammes Pimentel1, João Ricardo Malheiros de Souza2* , Arione Augusti Boligon1, Heden Luiz Marques Moreira3, Sandra Mara da Encarnação Fiala Rechsteiner3, Cláudio Alves Pimentel4, Charles Ferreira Martins5 1 Universidade Federal de Pelotas, Faculdade de Agronomia Eliseu Maciel, Departamento de Zootecnia, Campus Capão do Leão, Capão do Leão, RS, Brasil. 2 Universidade Federal de Santa Maria, Programa de Pós-graduação em Medicina Veterinária, Santa Maria, RS, Brasil. 3 Universidade Federal de Pelotas, Instituto de Biologia, Campus Capão do Leão, Capão do Leão, RS, Brasil. 4 Universidade Federal de Pelotas, Faculdade de Veterinária, Departamento de Patologia Animal, Campus Capão do Leão, Capão do Leão, RS, Brasil. 5 Universidade Federal de Pelotas, Faculdade de Veterinária, Departamento de Clínicas Veterinária, Campus Capão do Leão, Capão do Leão, RS, Brasil. ABSTRACT - This study used path analysis to establish the direct, indirect, and total effects of body linear and angular measurements on subjective morphological scores of the 247 Criollo horses that participated in their most important performance event, Freio de Ouro, in 2012. Freio de Ouro is the only event of the Criollo breed that considers morphology. Measurements of wither height, thoracic girth, cannon bone girth, body length, metatarsus length, croup length, shoulder width, head length, neck length, and upper neck girth, and the angles of rump, shoulder, and hock were taken. These morphometric measurements collectively explained 83% of the variation in morphological score. The measurements with the greatest total effects on score were neck length (correlation coefficient = 0.2300), upper neck girth (0.2100), angle of rump (−0.1600), thoracic girth (0.1400), shoulder width (0.1400), body length (0.1100), croup length (0.1100), shoulder angle (−0.1100), and metatarsus length (0.1000). These results mean that these variables have the highest association with morphological evaluation by referees. This is the first scientific study of the correlation of morphological measurements with judge evaluation in Criollo horses. Key Words: animal production, Criollo, equine, morphometry, path analysis Introduction 1978, the first functional competition was held in the municipality of Jaguarão, RS. This competition culminated Criollo horse is among the most populous horse breeds in the creation of the Freio de Ouro competition in 1982, in Brazil, and its socioeconomic importance to the Brazilian which aimed at the improvement and appreciation of equine culture is obvious, as it is largely responsible for functional horses (Affonso and Correa, 1992; Dalto, 2006). the growth and popularization of equine sports in Brazil The judgment at Freio de Ouro, as it has been (Lima and Cintra, 2015). Since its foundation in 1932, the since the beginning, takes into account conformation Associação Brasileira de Criadores de Cavalos Crioulos characteristics, in which a score for horse morphology is (ABCCC) has held expositions in which animals are judged added to the functional performance only at the end of for their conformation to the morphological standards the competition, to avoid invalidating the breed standard established by a breeder group; these standards are based certification and other morphological characteristics that on the criteria used in other countries, such as Uruguay and formed the foundation of the breed (ABCCC, 2015). The Argentina. Over time, the lack of agility of these Criollo morphological and functional evaluations are carried out horses has discouraged cattle ranchers and farmers, leading by three referees selected by the Technical Deliberative to a desire for and pursuit of more functional horses. In Council. The morphological evaluation is the result of subjective observations of many different body parts, in Received: January 24, 2018 Accepted: April 24, 2018 which all details should collectively present harmony, *Corresponding author: [email protected] nobility, and typicality for the breed (Souza, 1998). The Copyright © 2018 Sociedade Brasileira de Zootecnia. This is an Open Access article distributed under the terms of the Creative Commons Attribution License criteria implemented by the referees to determine the (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, morphological score are the same as used for the evaluation distribution, and reproduction in any medium, provided the original work is properly cited. at morphological expositions of the Criollo breed to 2 Pimentel et al. standardize the selection for breeding (ABCCC, 2016), and mean weight of 430±24.8 kg, measured during the although no score is assigned in the latter evaluations. The qualifying and final events of Freio de Ouro competition weight of the morphological score, in credentialing tests as in 2012. The work was performed in cities of the following well as the qualifying round and finals of Freio de Ouro, states: Rio Grande do Sul (Esteio, Pelotas, Santa Rosa, represents 37.2% of the final overall score (Dalto, 2006), Cachoeira do Sul, Caxias do Sul, and Carazinho), Santa highlighting the importance of morphology in the results Catarina (Lages), Paraná (Maringá), and Distrito Federal of the competition. This results in a desire for horses with (Brasília) in Brazil. Linear measurements of withers height, good morphology scores. The Freio de Ouro is the only thoracic girth, cannon bone girth, body length, metatarsus competition that considers morphology. length, croup length, shoulder width, head length, neck The morphological evaluations are always a great length, upper neck girth, and the angles of rump, shoulder, public attraction. A study published by ABCCC identified and hock were taken on the left side of the standing animal, that, of the factors considered in horse acquisition, more with all four legs on a horizontal and even floor. These than 75% of interviewees stated that morphological beauty, measurements are described in Pimentel et al. (2018). independent of the breed, was the most important item, Height, thoracic girth, and cannon bone girth followed by, with less intensity, genealogy, temperament, measurements were taken by ABCCC technicians, and the coat/hair, breed, and other characteristics (ABCCC, 2014). other measurements were taken by a trained member of the Three objective measures are used by ABCCC for research team. Morphological scores were given by referees registration purposes: wither height, thoracic girth, and at the beginning of the competition and were provided by cannon bone girth. Males must have a height ranging from the ABCCC for this study. The referees initially judged 140 to 150 cm, a minimum thoracic girth of 168 cm, and from the ground, and the animals were led by halters. a minimum cannon bone girth of 18 cm. For females, the Descriptive and path analyses (Cruz et al., 2004) height ranges from 138 to 148 cm, and minimum thoracic were conducted using R software (R Core Team, 2016). and cannon bone girths are 170 cm and 17 cm, respectively Path analysis was performed to determine the direct, (ABCCC, 2016). Other morphologic virtues and defects indirect, and total effects that the morphometric measures are evaluated subjectively. This approach is also used for (explanatory variable) had on the morphological scores evaluating other breeds (Mawdsley et al., 1996; Beeman, (principal variable) of referees. This analysis, developed 2008; Lage et al., 2009). by Wright (1921), is a method used to illustrate and With the introduction of Chilean bloodlines in the explain the associations between different characteristics 1970s, there have been morphological modifications to and to classify the correlations among them as direct and the Criollo breed; for example, the previous square-shaped indirect effects. body was replaced by the current rectangular shape, although this might be a perception due to variability in Results subjective morphological evaluations rather than a true change. The present study was performed to determine The morphometric measurements (Table 1) explained the magnitudes of the associations of linear and angular 83% (R2 = 0.83) of the variation in the morphologic score. morphological measurements with the most subjective None of the associations were high, and neck length showed morphological scores given by the referees to the horses the highest direct and total effects (correlation coefficients attending the Freio de Ouro. This work is the first report on of 0.2301 and 0.2300, respectively) on the morphological this subject. It provides scientific data and consistent tools score (Table 2) with no indirect effect, indicating that the to horse referees, technicians, and breeders and contributes effects of other variables were not responsible for the to standardization of morphological evaluations in Criollo magnitude of correlation. horses. Discussion Material and Methods According to the breed standard, the neck should This study was approved by the local Ethics and be tightly coupled to a large head by a large and clean Welfare Committee (CEEA), under case no. 3.943. All upper neck, the upper edge slightly convex, with thick