Increasing xylazine dose-enhanced anesthetic properties of telazol-xylazine combination in swine

We evaluated combinations of telazol, ketamine, and xylazine (TKX), telazol and xylazine (TX), telazol, xylazine, and xylazine (T2X), and ketamine and xylazine (KX) for chemical restraint and anesthesia induction in swine. Forty healthy mixed-breed pigs were randomly assigned to the four treatment groups with 10 pigs in each group. For TKX, TX, and T2X combinations, anesthetics were premixed by adding xylazine and ketamine, sterile water and xylazine, or xylazine alone directly into the telazol vial. For KX, anesthetic agents were drawn up separately, then mixed in the same syringe immediately before injection. All anesthetics were given as a single intramuscular injection. All four anesthetic combinations induced a rapid onset of sternal recumbency within 1.55 +/- 0.5 min and lateral recumbency within 2.27 +/- 0.6 min in pigs after intramuscular injection. There was no significant difference among treatments in these regards. The T2X combination induced a significantly longer duration of analgesia than did either TKX, TX, or KX. The T2X combination also induced a significantly longer duration of tolerance for endotracheal intubation and duration of lateral recumbency. Heart and respiratory rates were not significantly different among the four treatment groups. Vomiting was not observed in any of the treated pigs throughout the procedure. Recovery quality and duration from time of drug administration to recovery of pig walking unassisted were similar in three treatment groups but was shorter in KX-treated pigs. We concluded that all four anesthetic combinations were suitable for chemical restraint but that only TKX, TX, and T2X were suitable for anesthesia induction in pigs.(ABSTRACT TRUNCATED AT 250 WORDS)