SPECIAL CONSIDERATIONS IN THE USE OF CALVES 
FOR CARDIOVASCULAR IMPLANT STUDIES 
F. T. Galysh and R. F. Wallin* 
Calves offer the following advantages as experimental 
surgical subjects: suitable body size comparable to 
man, general availability, tractability, and adaptability 
to laboratory animal quarters. Disadvantages include: 
rapid growth, thoracic conformation unlike that of 
man, foaming of blood during extracorporeal oxygena- 
tion, and the requirement for special handling and 
housing facilities. A conditioning program developed in 
our laboratories includes specifications for weaning, vi- 
tamin supplementation, feeding, vaccination and para- 
site control. The management of the principal diseases 
of laboratory calves, pneumonia, gastroenteritis and 
ringworm are detailed. Special handling equipment is 
described for aseptic collection of donor blood from 
large calves, for weighing and transport, and for pose- 
operative care of calves. In our laboratories, anesthesia 
in calves is induced with 5% halothane and maintained 
with 0.25 to 0.75% halothane and 50% nitrous oxide 
with oxygen. During extracorporeal circulation succi- 
nylcholine and meperidine are used to maintain immo- 
bility and analgesia. Lung inflation pressures of 25 to 
30 cm H:0 during surgery and the postoperative use of 
a volume-cycled ventilator delivering 10 to 15 ml /kg 
tidal volumes have aided in preventing atelectasis. We 
have carried out over 100 normothermic cardiopulmon- 
ary bypass procedures in calves with disc or bubble ox- 
ygenators utilizing fresh whole blood and lactated Ring- 
er's solution as priming fluid. Perfusion flows have 
ranged from 4 to 6 liters per minute and perfusion 
pressures from 80 to 100 mm Hg. In these procedures 
blood gas values were as follows: PaOz, > 100 mm 
Hg; PaCO., < 40 mm Hg, and arterial pH, > 7.30. 
Foaming of calf blood was controlled by adding 2 to 3 
grams of Pluronic F-68 to the oxygenator. 
INTRODUCTION 
Recently a variety of the larger mammalian 
species has been used in the surgical laboratory 
for the implantation of cardiovascular devices. 
In many cases, the calf has evolved as the ani- 
mal of choice in these studies ; and since the calf 
is a relative newcomer to the laboratory, it has 
created some new problems. A number of pa- 
* Travenol Laboratories, Inc. Morton Grove, Illinois 60053. 
pers at this conference consider in depth the 
criteria for selection of animal species for par- 
ticular devices. This paper is based on our expe- 
rience in the development and evaluation of cir- 
culatory assist and related devices and deals 
with some special considerations in the use of 
calves as experimental surgical subjects. These 
include: (1) advantages and disadvantages of 
the calf for cardiovascular surgery, (2) condi- 
tioning of the calf for laboratory use, (3) com- 
mon laboratory diseases and their control, (4) 
special techniques and equipment for handling 
calves, (5) anesthesia and pulmonary ventila- 
tion, (6) perfusion techniques and prob- 
lems, and (7) anatomical considerations. 
THE CALF AS AN EXPERIMENTAL ANIMAL 
Advantages 
Body size and general availability are proba- 
bly the main reasons that the calf has become so 
widely used in recent years in experimental car- 
diovascular surgery. Under three months of 
age, the calf is comparable to man in overall 
body size and is thus more suitable than the dog 
and other standard laboratory animals for the 
study of devices and techniques intended for use 
in man. Because of their importance as farm 
animals cattle are available in most parts of the 
country, and calves, especially male animals of 
the dairy breeds, generally can be economically 
purchased for laboratory use. Supply and avail- 
ability are certainly more limited for species 
such as miniature swine, goats, ponies and even 
large sheep and dogs. The heart and major ves- 
sels of the calf are large and easily exposed and 
the vessel walls are strong and withstand sutur- 
ing. Cardiovascular parasites such as the canine 
heartworm do not occur in this species. Calves 
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