J. N. ROSS, JR., J. M. FUQUA, JR., B. S. RUARK AND J. H. KENNEDY 
419 
i 
16' 
21 i ' 
21 
"11 
21' 
0> 
■30" 
2 
-30" 
-30 
II 
alley 
STALLS 
4 
-30 
II 

5 
-30"* 
6 
-30"* 
7 
21' 
33' 
= sloping — 
= ramp _E: 
1 
9' 
i 
BAYLOR COLLEGE OF MEDICINE 
CALF FACILITY 
Figure 2. — Line drawing showing dimensions of facility used to accommodate calves in the immediate pre- and post- 
operative periods. 
Following tracheal intubation, anesthesia is 
maintained with a mixture of 0.5 to 1.0% halo- 
thane in equal parts of nitrous oxide and oxygen. 
A peroral stomach tube is inserted into the 
rumen to prevent gastric tympany from de- 
veloping during the operative procedure. In 
artificial heart implantation procedures a tra- 
cheostomy is performed facilitating prolonged 
postoperative ventilatory assistance if neces- 
sary. 
Once the chest is open, ventilation is mechan- 
ically maintained by the use of a Bird 4/8 com- 
bination anesthesia assister-controller and/or 
by manual means. It is necessary to use in- 
spiratory pressures of 28-33 cm H2O to prevent 
alveolar collapse in this species.'^ The effective- 
ness of anesthetic management is periodically 
assessed by the analysis of arterial blood sam- 
ples (pH, PO2, and PCO2). During most surgical 
procedures, the animals are maintained in light 
surgical anesthesia. Muscle relaxation, when 
necessary, is obtained with the use of intra- 
venous succinylcholine chloride. 
Thoracic Surgery and Cardiopulmonary 
Bypass (CPBP) 
In our experience, the calf is particularly suit- 
able for CPBP. Intravascular cannulation can 
be accomplished via a variety of surgical expo- 
sures. However, median sternotomies are 
avoided whenever possible because of complica- 
tions which arise when placing the calf in dorsal 
recumbancy. These complications include venti- 
lation/perfusion imbalances in the lung and the 
rapid development of ruminal tympany (bloat). 
Increased pressure of abdominal viscera on 
great vessels causes obstruction of venous re- 
