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| Author(s): |
Mayara Goncalves Fonseca
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Jaboticabal. 2018-06-15. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal |
| Defense date: | 2018-05-04 |
| Advisor: | Guilherme de Camargo Ferraz; Amanda Piaia Silvatti |
| Abstract | |
Considering the national significance of the Mangalarga Marchador (MM) breed and its increasing internationalization, studies that evaluate different aspects of their singular gaits, marcha batida (MB) and marcha picada (MP) are necessary. The objectives of this study were to describe and compare the kinematic variables (VCine) of MB and MP and to verify associations between the morphometric measurements and the VCine of MM horses; to evaluate the influence of the mutant allele of DMRT3 on homozygous (AA) or heterozygosis (AC) in the MP movement pattern; to identify, through genome-wide association study (GWAS), single nucleotide polymorphisms (SNPs) and genomic regions containing possible genes responsible for the phenotype of the MB in MM breed. For kinematic analysis, eighteen optoelectronic cameras (240 Hz) were positioned to acquire the three-dimensional data of three retroreflective markers fixed to the hooves. Duration, length, frequency and speed of each stride; diagonal advanced placement and lift-off and support phases (quadrupedal, tripedal, bipedal, Monopedal and suspension) were determined. Fortyeight horses belonging to the two gait groups, MP with AA and AC genotypes of the 22999655C>A SNP (n = 20) and MB with CC genotype (n = 28), were analyzed using the Equine SNP70 BeadChip and then performed GWAS. For kinematic characterization of the gaits, the data were submitted to descriptive analysis. For comparison between females and males, and for comparison between MB and MP, the support phases were compared by the Mann-Whitney U test and the other variables analyzed by Student's t-test (P ≤0.05). The relationship between morphometric and kinematic variables was evaluated by Pearson correlation. The temporal kinematic variables of MP horses of genotype AA (n = 9) and AC (n = 9) were compared by two-way ANOVA (genotype and stride, being the last of repeated samples) and then Tukey's test (P≤0.05). MB at the average speed of 13.22 km.h -1 presented higher percentage of diagonal bipedal support, followed by a single pelvic limb, triple thoracic limb, lateral bipedal and bipedal pelvic limbs. In MB, a positive diagonal advanced placement was also identified that is probably related to the manifestation of single-support and pelvic bipedal supports. MP at the average speed of 12.68 km.h -1 presented predominance of lateral supports followed by diagonals, triple of thoracic limb and single support of pelvic limb. At the same speed, MP horses presented shorter duration, shorter length and greater frequency of strides, greater dissociation and greater occurrence of lateral and triple supports, and lower frequency of diagonal supports, bipedal pelvic and suspension in relation to MB. In the studied sample, both MB and MP, the proportionally larger horses with smaller scapulohumeral, metacarpophalangeal, coxofemoral and tibiotarsometatarsal angles showed greater stride length and better distribution of support phases according to vii breed standard. Was found a relationship between the gait pattern and the different genotypes of DMRT3 (AA or AC) in the MP of ridden MM horses. AC individuals had lower diagonal advanced at lift-off and presented greater proportion of diagonal supports and therefore appeared to present distribution of support phases closer to that described as ideal in breed standard when compared to AA subjects. The GWAS results revealed that, unlike the MP phenotype that is apparently determined by single gene (DMRT3) in which the A allele of g.22999655C> A controls the characteristic, MB seems to be controlled by a greater number of genes. It was concluded that morphometry and genetic aspects interfere with the gait pattern of MB or MP Mangalarga Marchador horses. (AU) | |
| FAPESP's process: | 15/17155-2 - MANGALARGA MARCHADOR: MORPHOMETRIC, KINEMATIC AND GENETIC STUDY OF MARCHA BATIDA AND MARCHA PICADA GAITS |
| Grantee: | Mayara Goncalves Fonseca |
| Support Opportunities: | Scholarships in Brazil - Doctorate |