Hi there! I am back with news from the veterinary world. This month, it’s all about the birds!🐦

First, a paper on the effectiveness of sedation after intranasal administration of midazolam and midazolam-butorphanol in cockatiels. The researchers tested adult cockatiels for sedation with midazolam (3 mg/kg), mid­azolam-butorphanol (3 mg/kg for each drug), or sterile saline (0.9% NaCl) solution for the control treatment, all administered intranasally. They found no adverse reactions, and the average volume was 0.06 mL for midazolam and 0.03 mL for butorphanol. The level of sedation reached was found sufficient for non-painful or minimally painful procedures, such as physical exam, venipuncture, beak/nail trim, and diagnostic imaging. It is worth noticing that cloacal temperature increased significantly for all treatments during the restraint period, suggesting that the birds were able to physiologically respond to restraint stress, despite evident sedation. It may be because the doses were insufficient to result in complete abolition of stress response, or that stress response to manual restraint cannot be completely abolished without heavy sedation or general anesthesia. Lastly, the combination of midazolam and butorphanol was more effective than midazolam alone.

Second, we have a study performed to assess the pharmacokinetics and dynamics of methadone in chickens. Methadone (6 mg/kg) was ad­ministered IV and IM to isoflurane-anesthetized chickens , and cardio-respiratory variables were compared between treatments, and over time. Their results showed that the heart rate of the animals decreased after the injection of methadone, and then returned to baseline at 240 minutes, when most of them laid an egg. 🥚 The drug had a large volume of distribution, high clearance and high bioavailability after IM administration. The high clearance may be explained  by the high lipid solubility of the drug, which is transferred from central compartment to highly perfused organs such as liver, kidneys, and lungs. One of birds the developed evntricular premature contractions after IV treatment. Important: withdrawal times were not established for this drug for meat or eggs!

Lastly, we have a paper  on the evaluation of the thermal antinociceptive effects of hydromorphone hydrochloride in orange-winged Amazon parrots (Amazona amazonica). The parrots received hydromorphone (0.1, 1, and 2 mg/kg) or 0.9% NaCl solution (1 mL/kg; control) IM. Each bird was assigned an agitation-sedation score, and the thermal foot withdrawal threshold (TFWT) was measured at predetermined times before and after treatment administra­tion. The mean TFWT did not differ significantly between 1 and 2 mg/kg doses at any time, and the birds were less tolerant of increases in the perch temperature as their baseline TFWT increased, even though these doses resulted in significant increase in TFWT compared with IM administration of saline. A sex difference was observed, with mean TFWT for male birds being significantly lower than females. On a side note, it is unclear whether effective pain management in psittacines can be achieved by means of mu opioid receptor activity only, because studies are lacking. None of the birds in this study became sedated, and many of them became noticeably agitated. Nausea, ataxia, and miosis were all observed, and are all possibly related to the activation of mu opioid receptors. They concluded that hydromorphone should be administered with caution due to need to evaluate cardiorespiratory and thermic effects of the drug in parrots.

See you next month!