1034 
ANIMAL RESOURCES 
are tractable, easily handled animals which 
adapt readily to confinement in pens in labora- 
tory animal quarters. 
Disadvantages 
The immaturity of the calf, and its rapid 
growth and the associated restrictions on the 
age and weight range of usefulness in the labo- 
ratory probably represent the greatest disad- 
vantages of the boving species. Holstein-Frie- 
sian calves are approximately 45 kg at birth 
and normally gain % kg each day until they 
weigh about 160 kg. For experimental cardio- 
vascular surgery, calves weighing 65 to 130 kg 
are commonly used. The importance of the 
calf's rapid growth is readily apparent; calves 
cannot be stocked and held for later use since 
they quickly outgrow useful weight ranges; 
technical or procedural delays of a week or two 
sometimes allow calves to grow too large for a 
study, thus creating additional delays; and in 
survival studies, calves rapidly outgrow im- 
planted devices, thus limiting the opportunity 
for long term follow-up. 
The apical chest of the calf is grossly unlike 
the broad, flattened chest of man and can pre- 
sent some unique problems in the surgical in- 
stallation of bulky devices designed for use in 
man. Bovine blood readily foams during extra- 
corporeal oxygenation and special precautions 
must be taken to defoam the blood before recir- 
culation into the body.^ Ruminant species re- 
quire special handling to prevent aspiration of 
regurgitated rumen contents and fatal rumen 
distention (bloating) during general anes- 
thesia.2 Methods must be developed for 
transporting anesthesized and dead calves and 
disposing of carcasses. Calves require special 
housing facilities not generally available in lab- 
oratory animal quarters; thus renovation or 
new construction is often necessary before this 
species can be properly maintained. In spite of 
the advantages it offers over other species, the 
calf is obviously not a completely ideal animal 
for experimental cardiovascular surgery. 
Conditioning and Management of Calves 
laboratory use should be obtained from reliable 
sources of healthy animals, preferably commer- 
cial breeders with whom a satisfactory condi- 
tioning program has been developed. A stand- 
ing order and a regular delivery schedule for a 
fixed number of calves help to assure the quality 
of calves received. Conditioning requirements 
may vary from one location to another and 
from one time to the next. The program out- 
lined below has been successfully used by our 
supplier^ for over a year and may be modified 
as necessary. The animals we purchase origi- 
nate from a large breeding farm where all 
calves are subjected to this program and those 
destined for laboratory use are selected by a 
veterinarian based on uniformity, individual 
history and physical examinations. 
General Specifications 
Calves must be of Holstein-Friesian type 
usually weighing 65 to 130 kg and raised in ac- 
cordance with a sound herd health program. 
For a particular series of studies, a 10 kg 
weight range is specified in advance. Calves 
may be of either sex but are usually males cas- 
trated when 4 to 5 weeks of age. Calves which 
have received colostrum are taken from the cow 
at 3 to 7 days and transferred to individual 
stalls maintained at ambient temperatures 
which are moderated to 55 to 60°F during win- 
ter months. A single intramuscular injection of 
water-emulsifiable vitamins A, D and is 
given at this time. For the first 4 to 5 weeks, 
calves are bucket-fed increasing quantities of a 
milk replacer containing 24% protein and 20% 
fat. Solid food in the form of a commercial calf 
starter ration*^ is offered after the first week 
and is gradually increased in quantity until the 
calf is consuming 750 to 1000 grams daily and 
can be weaned. Water should be available at all 
times. We have purposely avoided feeding 
roughage such as hay which would cause block- 
age of laboratory drains. A low roughage diet 
has proven to be satisfactory in calves up to 225 
kg. 
At 2 to 3 weeks of age, calves are injected 
with a combination parainfluenza-3 vaccine and 
The essentials of calf husbandry apply both 
on the farm and in the laboratory.^ Calves for 
* Pel-Freez Bio-Animals, Inc., Rogers, Arkansas 72756 
B A-D-E 500, Bio-Ceutic Labs, St. Joseph, Missouri 64502 
Calf Startena, Ralston Purina Co., St. Louis, Missouri 63199 
