for dogs. Most surgeries in ruminants can be performed with regional anesthesia. General anesthesia is commonly used in animals for major surgery. Animals are often premedicated intravenously or intramuscularly with a sedative, analgesic, and anticholinergic agent (dogs frequently receive buprenorphine and acepromazine). The next step is induction, usually with an intravenous drug. Dogs and cats commonly receive thiopental (no longer allowed in the UK), ketamine with diazepam, tiletamine with zolazepam (usually just in cats), and/or propofol. Alfaxalone is a steroid anaesthetic used in many practices in the UK to induce anaesthesia in cats and sometimes dogs. It is similar in physiological effect but different in composition to the now withdrawn Saffan. Horses commonly receive thiopental and guaifenesin. Following induction, the animal is intubated with an endotracheal tube and maintained on a gas anesthetic. The most common gas anesthetics in use in veterinary medicine are isoflurane, enflurane, and halothane, although desflurane and sevoflurane are becoming more popular due to rapid induction and recovery. Common veterinary surgeries Elective procedures Elective procedures are those performed on a non-emergency basis, and which do not involve immediately life-threatening conditions. These are in contrast to emergency procedures. Sterilization surgery One of the most common elective surgical procedures in animals are those that render animals incapable of reproducing. Neutering in animals describes spaying or castration (also please see castration). To spay (medical term: ovariectomy or ovario-hysterectomy) is to completely remove the ovaries and often the uterus of a female animal. In a dog, this is accomplished through a ventral midline incision into the abdomen. In a cat, this is accomplished either by a ventral midline abdominal incision, or by a flank incision (more common in the UK). With an ovariectomy ligatures are placed on the blood vessels above and below the ovary and the organ is removed. With an ovariohysterectomy, the ligaments of the uterus and ovaries are broken down and the blood vessels are ligated and both organs are removed. The body wall, subcutis, and skin are sutured. To castrate (medical term: orchiectomy) is to remove the testicles of a male animal. Different techniques are used depending on the type of animal, including ligation of the spermatic cord with suture material, placing a rubber band around the cord to restrict blood flow to the testes, or crushing the cord with a specialized instrument like the Burdizzo. Neutering is usually performed to prevent breeding, prevent unwanted behavior,