Effect of chronic tracheal bypass implant on the nasal breathing in sheep.

Three sexually matured Rambouillet ewes were surgically implanted with a reversible, tracheal bypass canula. A total of seven trials were made on three resting, unanesthetized sheep in standing position. The ambient temperature was kept constant at 18 degrees C in order that any change in nostril temperature could not be attributed to any fluctuation of this environmental temperature. In all trials, the nostril temperature increased (6 degrees C) when the animal was placed on tracheal (bypassed) breathing and it decreased when the sheep was changed to normal nasal breathing. This paper describes a procedure to study the effects of prolonged interruption of normal nasal breathing.