Anaesthesia of calves for tomography examinations with Xylazine or Tiletamine-Zolazepam

Preparations containing Xylazine and Tiletamin-Zolazepam active ingredients mere used in a pilot study involving 15 Holstein-Friesian crossbred calves of both sexes to evaluate them for the purpose of anaesthesia in computer- assisted tomography (CT). The animals were assigned to three groups of equa l sizes. In Groups 1 and 2 Xylazine (Rometar) was administered intravenousl y vs, intramuscularly, respectively, while in Group 3 a mixture of Tiletami n-Zolazepam (I:I) (Zoletil), was administered intramuscularly. Times to lie down, of subsequent immobility, to regain consciousness and to full recove ry were recorded. The physiological status of calves was monitored while th ey were anaesthetised. In accordance with relevant literature data, intrave nous administration of Xylazine resulted in lying down and narcosis more ra pidly than was the case with intramuscular application. Since only 15 minut es are required for (CT) examination when anaesthesia can be reversed with an antidote (e.g Yohimbin), thus a continuous working routine can be achiev ed. Similarly to other species, there were substantial within-group deviati ons observed in the recorded parameters of the calves revealing different l evels of individual sensitivity to identical doses of the anaesthetic. The preliminary results obtained in this study indicate that the Tiletamin-Zola zepam anaesthetic combination is suitable for effective application in calv es for CT examination without any substantial side-effects.