The objective of our research was to estimate the therapeutic index and assess the interaction of alfaxalone (IP) with ketamine or xylazine (IM) in chicks by using isobolographic analysis. The up-and-down technique was involved to calculate the median effective anesthetic dosages (ED50) of alfaxalone, xylazine, and ketamine given separately or at the same time in young chicks. Then the up-and-down technique was involved to estimate the median lethal dosage (LD50) of alfaxalone (IP) to determine the safety profile. The ED50 of all anesthetics was evaluated isobolographically to assess the type of interaction between alfaxalone and xylazine or alfaxalone and ketamine. The alfaxalone ED50 was 32.88 mg/kg (IP), whereas the LD50 was 102.40 mg/kg (IP). The ED50 values for alfaxalone, ketamine, and xylazine were 32.88, 12.24, and 2.45 mg/kg, respectively. The ED50 values of alfaxalone with ketamine or xylazine (25:25 ED50 values) were: 7.39+2.35, and 8.61+0.63 mg/kg, respectively. ED50 values were decreased when the combinations of alfaxalone/ketamine or alfaxalone/xylazine were administered by 22-21% and 26-25%, respectively. The anesthesia of chicks with alfaxalone is safe, produces a surgical stage of anesthesia, and can be used for minor surgical procedures. The use of alfaxalone with ketamine or xylazine has been shown to have a synergistic effect and these findings may be of clinical relevance in poultry or may be extended to mammals following further clinical trials.

O BJECTIVE, alfaxalone is a neuro-steroidal anesthetic agent. The data on the anesthetic properties of alfaxalone in the birds is relatively inadequate. This article studies the anesthetic effect and efficiency of alfaxalone /ketamine or alfaxalone /xylazine anesthesia given in 7-10 day-old chicks. Methods, We used the up and down method to determine the median effective anesthetic dose of alfaxalone, time to onset of anesthesia, duration of action, temperature, respiratory rate, and antagonize with flumazenil were evaluated. Results, The median effective anesthetic dose (ED 50 ) of alfaxalone was 32.88mg/kg . intraperitoneally. Alfaxalone at 25, 50, and 100 mg/kg induced anesthesia in chicks for (10 -48 minutes). Flumazenil decreased the anesthetic period of alfaxalone. Alfaxalone at 50mg/kg causes bradypnea whereas at 100 mg/kg causes tachypnea. Alfaxalone produce hypothermia. The duration of anesthesia was significantly longer in alfaxalone/xylazine than in alfaxalone/ketamine but it causes more bradypnea. Conclusion, alfaxalone produces light surgical anesthesia so that it can be mixed with ketamine or xylazine for deep surgical anesthesia. Flumazenil may reverse the anesthetic effect of alfaxalone.