Avaliação radiológica do terceiro metacarpiano em potros Puro Sangue de Corrida em treinamento

Abstract

Forty two 2-year-old thoroughbreds were examined clinically and radiographicaly each 15 days during their initially training program to determine the incidence and the predisposing factors to dorsal metacarpal disease (DMD). During the first period 25 2-y-0 were followed during 2 month and at the second year followed up was performed for 4 month on 17 2-y-0. Data like gender, mean speed, distance of breezing and trainer were also collected. At the first year 28% of the 2-y-0 showed DMD and at the second 70,6% got DMD, with total incidence being 45%. No difference on incidence and mean speed of breezing was found between genders. Speed of affected and non affected horses remained between 16 and 18m/s. On 2,5 and 3,5 furlongs mean breezing speed of DMD affected horses was higher (p<0,05). 10 out of 19 horses showed DMD signs at the distance of 3,5 furlongs. There was a difference between trainers regarding incidence of DMD and speed of their horses. 2-year-olds under care of trainers whose horses had the highest incidence o DMD also were the fastest one’s. X-rays were taken using latero-medial projection. Dorsal cortex (DC) was evaluated on the X-rays and DC, palmar cortex and medular zone were measured in order to determine the radilogic index (RI). No radiographic alterations were observed on the DC of the McIII of horses affected by DMD. Mean increase in DC thickness of healthy McIII was 0.82mm and 0.49mm on the right and left side. DMD affected McIII had a DC increase of 1.16mm and 1.96, respectively. None affected right McIII had a RI of 2.00 at the first evaluation and 2.50 at the last one and left ones had na I of 2.30 and 2.57, respectively. DMD affected McIII started with an index of 2.20 reaching 2.70 on the right side and 2.07 increasing to 3.00 on the left. There was a significant increase (p<0.05) in DC thickness and RI between evaluations of both, healthy and DMD affected McIII. DC thickness showed a significant increase between affected and non affected McIII. Na important increase in DC thickness was observed in the evaluation prior to DMD clinical signs. Speed associated with longer breezing distances (3,5 furlongs) and the trainer effect were factors predisposing young 2-y-0 to DMD. Increase in DC thickness could be used as a diagnostic tool for early recognition of DMD allowing adoption of preventive measures.