Evolution of Morphometric Measures in the Mangalarga Marchador Breed

Abstract

-The Mangalarga Marchador breed accounts for the largest horse herd in Brazil and has been experiencing national and international expansion. Nevertheless, there is little scientific production on the evolution of this breed and there are no studies on the morphometric transformations that took place during its formation. In this context, the present study aimed to assess the evolution in morphometric measures of the Mangalarga Marchador breed between 1970 and 2010. The research used information archived at the Brazilian Association of Mangalarga Marchador Breeders from 23,148 males and 92,980 females in a completely randomized experimental design. The six treatments consisted of the animals measured between 1970 and 1979, 1980 and 1989, 1990 and 1994, 1995 and 1999, 2000 and 2004, and 2005 and 2010, respectively. The measures assessed were: height at withers and croup, length of the head, neck, back, croup, shoulder, and body, width of the head and croup, thoracic circumference, and cannon circumference Over the period analyzed, males and females experienced a reduction in thoracic circumference, in the lengths of the head, back, croup, and shoulder, and in the widths of the head and croup. In the males, neck length and cannon circumference also decreased, while body length increased in females. Over time, breed selection led to smaller head, higher stature, and shorter trunk length. However, important measures for the breed's functionality, such as shoulder length and thoracic circumference, decreased.Keywords: Height. Length. Horses. Width. Circumference. EVOLUÇÃO DAS MEDIDAS MORFOMÉTRICAS DA RAÇA MANGALARGA MARCHADORRESUMO -A raça Mangalarga Marchador é responsável pelo maior rebanho de equinos do país e tem alcançado crescente expansão nacional e internacional. Apesar disso, é escassa a produção científica sobre a evolução dessa raça e não existem estudos sobre as transformações morfométricas que ocorreram ao longo de sua formação. Neste contexto, o presente estudo objetivou avaliar a evolução das medidas morfométricas da raça Mangalarga Marchador entre 1970 e 2010. Foram utilizadas informações arquivadas na Associação Brasileira dos Criadores do Cavalo Mangalarga Marchador de 23148 machos e 92980 fêmeas, em delineamento experimental inteiramente ao acaso. Os seis tratamentos foram constituídos pelos animais mensurados de 1970 a 1979, 1980 a 1989, 1990 a 1994, 1995 a 1999, 2000 a 2004 e 2005 a 2010, respectivamente. As medidas avaliadas foram: alturas na cernelha e garupa, comprimentos da cabeça, pescoço, dorso-lombo, garupa, espádua e corpo, larguras da cabeça e da garupa, além de perímetros torácico e da canela. Ao longo do período avaliado observou-se nos machos e fêmeas redução do perímetro torácico, dos comprimentos da cabeça, dorso-lombo, garupa e espádua e das larguras de cabeça e garupa. Nos machos houve também redução no comprimento do pescoço e aumento no perímetro da canela. Nas fêmeas verificou-se aumento no comprimento do corpo. Ao longo do tempo, a seleção da raça conferiu aos anim...

Curva de crescimento em altura na cernelha de equinos da raça Mangalarga Marchador considerando-se heterocedasticidade

“…Ainda se comparando os resultados encontrados por Santiago et al (2016) com os do presente estudo, observa-se que a altura na cernelha na idade adulta para fêmeas (Tab. 2) continua com uma tendência de crescimento, ao passo que, para os machos, as estimativas para a altura na cernelha permanecem constantes, semelhantes aos valores observados por esses autores.…”

Effectiveness of the morphofunctional evaluation method of Campolina and Mangalarga Marchador breeds

“…In animal sciences, "physical compensations" are qualities in regions close to the technical defect that compensate or minimize the effects of such defects on animal function (McManus et al, 2005;Santiago et al, 2016). Thus, horses with flaws in some regions of the body may be penalized in the morphological judgment and, due to physical compensations that neutralize these defects, perform well in marcha judgments, which hampers correlating the results of the two judgments.…”

Morphometric characteristics of the Mangalarga Marchador horse breed determined by nonlinear models

“…The morphometric variables determined were: height at the withers, measured from the highest point of the interscapular region, located in the space defined by the T5 and T6 spinal processes, to the ground; body length, distance between the cranial portion of the major humerus tubercle and the caudal portion of the ischial tuberosity; thoracic perimeter, circumference measured just after the end of the withers, between the T8 and T9 spinal processes, passing through the intercostal space of the eighth and ninth vertebrae until the joint between the last rib and the xiphoid process; and cannon perimeter, circumference measured in the median region of the left shin, formed by the metacarpal bones II, III, and IV. A single examiner performed all measurements on the left side of the animal in stance position, i.e., four limbs supported and head in normal position, according to Cabral et al (2004) and Santiago et al (2016). The used tools included a height rod for measurement of height and length, and two 2-m measuring tapes, with 0.1 and 0.01 cm precision to measure the thoracic and cannon perimeters, respectively.…”

“…In these models, animal growth is typically determined by morphometric measurements (Lawrence & Fowler, 2002;Cabral et al, 2004;Santos et al, 2007;Rezende et al, 2016), including height at the withers, body length, and thoracic and cannon perimeters. These variables are usually studied because they reflect bone length and diameter, being related to the skeletal bone quality and the cardiorespiratory and workload capacity of horses during training exercises (Berbari Neto, 2009).…”