Читать книгу Farm Animal Anesthesia - Группа авторов - Страница 31

When administered at 0.02 mg/kg IM to cattle, romifidine produced deep sedation with recumbency at 14.8 ± 3.4 minutes after injection. The duration of immobilization was 45.2 ± 3.4 minutes, and standing recovery occurred at 78.7 ± 17.7 minutes. The degree of analgesia produced by romifidine at this dose was similar to that produced by 0.2 mg/kg of IM xylazine. Similar to other α₂ agonists, romifidine caused bradycardia, and the heart rate was significantly lower with romifidine. Other side effects of romifidine observed included bradypnea, decreased hematocrit, and ruminal tympany [72]. Romifidine (0.05 mg/kg) and morphine (0.1 mg/kg) have been combined and diluted in saline to a total volume of 30 ml and administered through a caudal epidural to Holstein–Friesian cows. Significant perineal analgesia with moderate sedation lasted 6 hours, but on occasion analgesia lasted up to 12 hours. Cows in this study tended to sit down and assume a recumbent position. The authors were not clear whether the recumbency was due to the deep sedation and ataxia from systemic absorption of romifidine and morphine into the blood circulation or the natural instinct of the cattle to sit down during sedation. One cow developed hind limb paresis and became recumbent 24 hours after drug administration. The cow showed no improvement 72 hours later and was humanely euthanized. Postmortem examination did not reveal any pathological changes like necrosis, inflammation, or degenerative lesions in the spinal cord to explain the hind limb paresis. However, the cow did have severe muscle necrosis of the adductor muscles, mild hepatic lipidosis, and moderate acute abomasal ulceration [73].