Halothane anesthesia in calves.

Because of the calf's popularity as an experimental animal and its often noted sensitivity to anesthetics and anesthesia, the potency of halothane was studied in eight, young (x = 5.85 weeks), healthy, male Holstein-Friesian calves. The minimal alveolar halothane-O2 concentration (MAC) which just prevented calf movement in response to a tail clamp was 0.76 +/- SEM 0.03 vol% and is less than predictions based on studies in man. The addition of 50% N2O to inspired gases decreased the halothane MAC to 0.59 +/- 0.03%. In the absence of common modifying factors of anesthesia, halothane-O2 caused cardiopulmonary depression in these calves in proportion to anesthetic dose. Only two (total protein and albumin) of 17 selected blood clinical biochemical values were significantly (P less than 0.05) altered from base line within seven days of anesthesia, indicating insults to major organ systems did not occur.