Agricultural Science Digest 
PURDUE UNIVERSITY
Vol. 13, Jan. - Feb., 1971

IS FEEDER CATTLE PRECONDITIONING
WORTHWHILE?

There is, apparently, very little differ-
ence in feedlot performance of cattle under
various handling practices before shipment,
when the amount of exposure and stress
placed upon them is minimal and cattle are
shipped directly from farm or ranch to feed-
lot. Cost of the preconditioning practices to
the rancher varied from $2.54 to $3.17 per
hundredweight.

This study, recently completed at Purdue,
answered the major issues revolving around
discussions of preconditioning programs for
feeder cattle--first, the amount of economic
benefit or sacrifice to the producer; and sec-
ond, what constitutes a preconditioning pro-
	gram.

Preconditioning has been defined as a
program of preparing cattle to withstand the
stress of movement and to prevent the
spread of diseases peculiar to movement of
the animals.

The study was designed to control and
measure both the physical and financial as-
pects of four methods of handling and precon-
ditioning feeder cattle. One hundred sixteen
cattle were used and four methods tested.
Cattle were weaned and shipped the same
day, weaned about 30 days prior to shipment
and placed on hay, grain, and supplement,
vaccinated with bovine virus diarrhea vac-
cine, infectious bovine rhinotracheitis and
parainfluenza - 3 vaccines approximately 45
days prior to shipment and weaned and
shipped the same day; and, finally, weaned
30 days prior to shipment and vaccinated as
in item 3.

	This is the first in a series of studies
delving into the cost-benefit relationships
of various preconditioning and handling pro-
grams for feeder cattle.

Journal paper 4040, K. B. Meyer, J. W.
Judy, Jr., J. H. Armstrong, Department of
Veterinary Science.

THE IMMUNITY RESPONSE TO INFECTIOUS
BRONCHITIS VIRUS

A need has existed to devise a reliable
means of investigating the immunity stimu-
lated to infectious bronchitis virus (IBV) in
chickens. Serological tests and various
other immunity challenge procedures to as-
sess these responses have encountered var-
iations in results. Although attempts at
standardizing various techniques have been
made, there is an important need to extend
these efforts because of the increasingly
complex pattern of infectious bronchitis
virus that has evolved in recent years.

This study concerns itself with criteria
for evaluating the immune response to sev-
eral IBV isolates from commercial vaccines.
Among them: IBV serotype, dosage of chal-
lenge virus, observation time for appearance
of signs and obtaining of tracheal swabs, and
attempted recovery of challenge virus. A
fluorescent antibody technique was also used.

The study showed that tracheal swabs
were not reliable indicators after the third
or fourth day PC, the fluorescent antibody
technique was of value in detecting infection
on the second, third and fourth days.

Establishment of a reliable, uniform
test for the virus will be of value to poultry-
men and veterinarians in combating IBV.
Journal paper 4090, R. W. Winterfield
and A. M. Fadly, Dept, of Veterinary Science.

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