Avaliação do desempenho de drogas quimioprofiláticas contra agentes da tristeza parasitária subclínica em novilhos superprecoces na Região Sul do Rio Grande do Sul

Abstract

In the present study were used Angus steers exposed to infestation by ticks Rhipicephalus (Boophilus) microplus, remnants of an outbreak of babesiosis and anaplasmosis. On day -1, the batch of 298 steers weighing an average of 225.11 kg (± 36.19), ADG had a weight of 0.662 Kg/day in the last 34 days. The plot was divided into three groups: Group 1 (Pirofort+Ourotetra) 68 steers with ADG below the plot average, with 0.285 kg/day, Group 2 (Imizol) 65 steers with ADG below the plot average, with 0.269 kg/day, Group 3 (Control) 36 steers with ADG above the overall average of the lot, with gains of 1.481 kg/day. The calves of group 1 were subjected to prophylaxis with 1.17 mg/kg of diminazene diaceturate and 6.7 mg/kg of long-acting oxytetracycline. The calves of group 2 were subjected to prophylaxis with 1.2 mg/kg imidocarb dipropionate. The Group 3 animals were not treated. Group 1 (Pirofort+Ourotetra) had the better performance of weight gain in the period (0.615 kg/day) and presented no clinical cases of disease during the experiment. The protocol chemoprophylaxis in Group 2 (Imizol) had superior performance than Group 3 (Control), with average ADG 0.488 and 0.280 kg/day respectively, but there were two clinical cases of anaplasmosis in the end of the experiment in Group 2 and Group 3 (control) showed one clinical case of anaplasmosis. The mean values of hematocrit did not differ between groups, only with a variation between the samples in Group 2, due to the low levels found in clinical animals. The protocols chemoprophylactic proved an important tool for the prevention of new clinical cases and the recovery and maintenance of the daily weight gain seeking rapid development and acceleration of cycles needed for efficiency in cattle of these categories