Temporal analysis of demographic and biometric parameters of the Mangalarga breed

Abstract

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 Associação Brasileira de Criadores de Cavalos da Raça 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 São 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.

Participation Frequency and Biometric Characterization of Mangalarga Horses that Attended National Shows of the Breed

“…Thus, the special attention provided to horses that participate in national shows enabled greater gene expression of the phenotype of the animal, translated into greater body development (Santiago et al, 2013). Such results corroborate those by Almeida et al (2021), who assessed the Mangalarga breed herd and reported values of the linear measurements studied always lower than those of horses that took part in national shows.…”

“…The fact Mangalarga females and stallions have reached higher registration scores than geldings indicate the selection by breeders, allied to the evaluation criteria used by registration technicians, using a scoring chart, reached the expected goal by eliminating from reproduction exactly individuals with lower scores (Almeida et al, 2021). Those results reinforce the importance of the genealogic registration system for the selection of phenotypically superior animals, eliminating undesirable characteristics from the herd.…”

“…To morphologically characterize the horses attending national shows and compare them among themselves and with the Mangalarga herd, information on the morphometric measurements of height at withers, thoracic circumference, and cannon circumference were extracted from the database of the genealogic registration system of ABCCRM of 4,133 horses taking part in national shows and 206,428 Mangalarga horses representing the breed herd. Two of those linear measurements were used to calculate the dactylthoracic index, mentioned by Almeida et al (2021):…”

“…In the process of formation of the Mangalarga breed, the search for animals able for sports practices, associated with the diagonal, comfortable gait, favored the expansion of the breed. However, breeders selected horses with such characteristics in an empirical manner, which led to the formation of a functionally superior herd, but that is morphologically heterogeneous (Almeida et al, 2021). In face of the need to standardize the animals of the breed, the Brazilian Association of Breeders of Mangalarga Horses (Associação Brasileira de Criadores de Cavalos da Raça -ABCCRM) was created in 1934, the same year the breed standard was instituted (ABCCRM, 2020).…”

“…In face of the need to standardize the animals of the breed, the Brazilian Association of Breeders of Mangalarga Horses (Associação Brasileira de Criadores de Cavalos da Raça -ABCCRM) was created in 1934, the same year the breed standard was instituted (ABCCRM, 2020). Currently, the ABCCRM has been orienting the breed selection to fit it into the concept of a saddle, work, and sports horse, maintaining the peculiar characteristics of the breed (Almeida et al, 2021).…”