Adriana Amfim

Studies for Growing Horses Evaluation for their Classification

The evaluation of English Thoroughbred growing horses (2 ½ years) was done individually, before they were tested for classification. It was based on the following criteria: origin and exterior appearance (body size, conformation and walk). Each character or trait was evaluated on a scale from 0 to 10. The evaluation of horse origin was done using the method of points, based on pedigree analysis. The evaluation according to body size was done by biometry and gravimetry, determining the height, body mass, thorax perimeter and cannon diameter. Body conformation was evaluated on three groups of body parts: head, neck and trunk; limbs; constitution, muscles, tendons and ligaments. For evaluation, the data were correlated with the animal genotypes, established by genetic markers. The genetic markers considered by the investigation were the haemoglobin and transferrin. Two genotypes were identified at the haemoglobin locus and five genotypes at the transferrin locus. After evaluation, the animals were classified as follows: 37% in record class; 51% in elite class and 12% in first class. The young horses classified in record and elite classes, which displayed a high geneticpotential were retained in the stud to be trained for classification. The balance was put out for sale.