The aim of this study was to evaluate a protocol of chemical restraint comparing the conventional method of calculation (weight dose) and allometric extrapolation. Twelve healthy red howler monkeys (Alouatta guariba clamitans), average weight 4.84±0.97kg, male and female, were used for this study. After a 12-hour period of food restriction and 6 hours of water restriction, the animals were physically restraint and the following parameters were measured: heart rate (HR), respiratory rate (RR), capillary refill time (CRT), rectal temperature (RT), non invasive systolic arterial pressure (NISAP) and arterial blood gases analysis. The animals were distributed into two groups: CG (Conventional Group, n=6), in which the animals received S(+) ketamine (5mg kg-1) and midazolam (0.5mg kg-1), by intramuscular (IM) injection; and AG (Allometry Group, n=6), in which the animals also received S(+) ketamine and midazolan IM, but the doses were calculated by allometric extrapolation. Parameters were evaluated at the following moments: M5, M10, M20 and M30 (5, 10, 20 and 30 minutes after IM injection, respectively). Muscle relaxation, pedal and caudal reflexes, interdigital pinch, recumbency time, sedation's quality and duration, and recovery time and its quality were also evaluated. The AG had a faster time for recumbency, higher period and quality of sedation, and a significantly reduction on HR and SAP from M5 to M30 when compared to CG. It was concluded that allometric extrapolation presented a better muscle relaxation and sedation without significant cardiorespiratory depression.
Alouatta guariba clamitans; midazolam; (S+) ketamine; allometric extrapolation
