Análise de componentes principais de medidas morfométricas de equinos da raça Pônei Brasileiro

The Brazilian Pony is a recent breed, with registration of animals only starting in 1970, since when it has been continually improved. Body morphometry is important for selective breeding of horses, because it is one of the main elements used to characterize breeds. The objective of this study was to apply principal component analysis (PCA) to the main morphometric measures of Brazilian Pony stallions and mares to identify those that contribute the most to explain the total variance in each sex. Fourteen linear measures were obtained from 281 adult animals and the data were used for to compute descriptive statistics and correlation coefficients as well as for analysis of variance and principal component analysis. The morphometric measures of the animals showed great variation in the two sexes. The correlations between the variables were positive and generally of large magnitude. For the stallions, only two components were necessary to explain at least 80% of the total variance, while for the females, three components were needed. After the methodology for discarding of variables, the variables head width, neck length and chest height were identified as the measures that explain most of variations in Brazilian Pony horses and should be uses for breed selection and control.