Temporal analysis of demographic and biometric parameters of the Mangalarga breed/Analise temporal de parametros demograficos e biometricos da raca Mangalarga

This study analyzed the demographic and biometric changes in registered animals of the Mangalarga breed over the decades. Information from 206,428 Mangalarga horses born between 1930 and 2018 extracted from the genealogic registry system of the Associaqao Brasileira de Criadores de Cavalos da Raca Mangalarga was employed. The data referred to sex, birth date, fur coat, breeding site location, score achieved at genealogic registration, and three body measurements. Height at withers and the thoracic and cannon bone circumferences were used to calculate five morphometric indices. Results were submitted to analysis of variance using a completely randomized split-plot design where the plots comprised the sexes and the split-plots comprised the decades of selection. Between 1930 and 1990, genealogic registrations progressively increased, particularly in the 1970s and 80s, when the herd experienced the highest growth rate. In 2018, Mangalarga breeding sites were reported in 23 Brazilian states and the states of Sao Paulo, Minas Gerais, and Bahia held the largest herds. Between 1970 and 2018, the height at withers of mares, stallions, and geldings increased by 5.1, 3.1, and 2.1 cm, respectively. The thoracic circumference of stallions increased by 3.3 cm and the cannon bone circumference of mares decreased by 0.34 cm. It is concluded that the Mangalarga breed is found across Brazil, especially in the Southeast region. Irrespective of sex, the selection of the breed has led to taller Mangalarga horses. In addition, the stallions became heavier and gained thoracic circumference, while mares became hypometric. Key words: horses, morphometric indices, linear measurements. Objetivou-se analisar as alteracoes demogrdficas e biometricas dos animais registrados da raqa Mangalarga, ao longo das decadas. For am utilizadas informaqoes de 206.428 equinos Mangalarga, extraidas do sistema de registro genealogico da Associaqao Brasileira de Criadores de Cavalos da Raqa Mangalarga. Dos animais nascidos entre 1930 e 2018, foram consideradas informaqoes referentes ao sexo, data de nascimento, pelagem, localizaqao do criatorio, pontuaqao obtida no ato do registro genealogico e tres medidas corporais dos equinos. Utilizando a medida de altura a cernelha e os perimetros tordcico e de canela foram calculados cinco indices morfometricos. Os resultados foram submetidos a analise de variancia, utilizando delineamento inteiramente ao acaso em esquema de parcelas subdivididas, sendo as parc