Evaluation of Ketamine as a General Anesthetic for Domestic Fowl Chicks

Abstract

Ketamine is a cyclohexanone derivative with analgesic and anesthetic properties. The drug is recommended for use in a wide range of avian species. Studies on its effects on small birds, however, are apparently lacking. In this study, the drug was tested in 3-day-old domestic fowl chicks administered as a single intramuscular (i.m.) injection at 2.5, 5, 10 or 30 mg/kg body weight. A dose of 30 mg/kg was instantly lethal to these birds. Drug toxicity was expressed by the formula y = 1.191x + 1.375 using probit analysis with LD50 and LD99 values at 40.83 and 81.97 mg/kg, respectively. The therapeutic index (TI) was 24.4 indicating a wide margin of drug safety. The time for onset of anesthesia was rapid (10- 60 seconds) depending upon dose level with drug dose and response inversely related (y = - 25x + 77.33). Recovery from anesthesia was consistently smooth and varied between 40-60 min also depending upon dose level. The dose and response, however, are positively correlated (y = 9.5x + 34). . Apart from transient salivation in one bird, no untoward effects were observed up to 3 weeks when the experiments were terminated. The domestic fowl (Gallus domesticus), as a species, is considered a unique experimental model in immunological research where surgical intervention at an early stage is the tool. This approach, however, requires an effective and a safe anesthetic agent for application in such small birds. Further clinical evaluation may prove ketamine a useful general anesthetic for domestic fowl chicks and perhaps other bird species.