North Dakota State University * Dickinson Research Extension Center
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483-2005
An Evaluation of Immune Response in Weanling Age Beef Calves Given Booster Vaccinations at Selected Intervals
A. Schipper, D. G. Landblom, J. L. Nelson and H. M. Smith
Objectives:
The primary objective when using vaccines is to prevent infectious disease. This objective
is too frequently not obtained because of incorrect administration of the biological
product. Investigations at this station to identify the method that would generate the
most immune response revealed that very minimal, or no antibody production was produced
following a single vaccination; and that regardless of the type of vaccine used (modified
live of inactivated) two vaccinations were required to produce maximum blood serum levels
of antibodies (Schipper et al, 1984). It was also found that when weaning and vaccination
occurs simultaneously, antibody titer is decreased and that a more rapid decay of antibody
titer occurs. When the previous work being discussed was done, an interval of three weeks
was used between the initial and booster vaccinations. The purpose of this present
investigation is to identify the interval between the initial and booster vaccinations
that will promote maximum antibody response among weanling age beef calves.
Procedure:
Calves weighing approximately 450-550 pounds of multiple breeds and of both sexes were
utilized in this investigation. The biological agent used was an inactivated trivalent
(Infectious Bovine Rhinotrachetis - IBR, Bovine Virus Diarrhea - BVD, and Para Influenza -
3-PI-3) vaccine administered according to the manufacturers recommendations. In the
vaccination protocol 46 calves served as controls and were intermingled with the treated
groups but received no vaccine. One group of 39 calves received a single administration (5
ml) of the trivalent vaccine when the experiment began. Three other treatment groups
comprised of 38 to 40 calves each were given an initial vaccination of the trivalent
vaccine and were then given booster vaccinations at either one, two or three week
intervals.
All calves were bled on vaccination day, on the day that booster vaccinations were given and six weeks following the initial vaccination. Blood serum was obtained, frozen and forwarded to the Veterinary Diagnostic Laboratory, NDSU where it was titered for antibodies to IBR, BVD and PI-3 viruses present in the trivalent vaccine.
Results:
IBR
Over the six week period of this investigation, control calves did not exhibit major
changes in blood serum antibody levels. All calves, regardless of the frequency or
interval that a booster vaccination was administered exhibited a definite blood serum
titer decay. The greatest antibody titer response was detected in those calves given a
booster vaccination two weeks following the initial vaccination.
BVD
Calves in the control group exhibited a slight increase in blood serum antibody titer
between the three and six weeks period of the investigation. A similar slight increase
occurred in varying degrees between the three and six weeks period for those calves given
an initial vaccination only and those given booster vaccinations at one and two weeks
after the initial challenge. A major increase in blood serum titer was observed for those
calves given a booster vaccination three weeks following the initial vaccination.
PI-3
The controls exhibited a steady increase in blood serum titer over the six weeks period
investigated. Administering a booster vaccination two weeks following the initial
challenge generated the greatest increase in blood serum titer to PI-3. With the exception
of the control group of calves, all calf groups exhibited a similar increase in serum
antibody titer following the three week period of the investigation.
Comparison of Immune Response for IBR, BVD, PI-3 Antigens.
The IBR vaccine provided the least antibody response and an antibody decay between the
third and sixth week of the study. Greatest antibody response was detected by those calves
receiving the PI-3 antigen following the three week booster vaccination.
Discussion:
IBR
Response among calves given the IBR (Herpes virus) antigen was substantially less
than that observed among calves receiving either BVD or PI-3 vaccine. Also these data
clearly indicate that IBR blood serum antibody decay occurs soon after maximum
post-vaccination titers are observed.
The blood serum titer decay observed is characteristic for nearly all Herpes viruses and has lead to the suggestion that continuous multi-vaccinations must be utilized to maintain a maximum level of antibody for protection from Herpes virus diseases. While this would maintain maximum antibody levels, it is an impractical approach.
BVD
The results relating to the immune response among calves vaccinated with BVD virus
indicates that there is little protection provided animals vaccinated only once, or
receiving a second administration at one or two weeks following initial vaccination. When
comparing BVD and IBR antibody titers, BVD exhibited a greater antigenic activity. It is
apparent from these data that those animals receiving a second vaccination three weeks
after the initial vaccination for BVD would have the greatest opportunity to develop
maximum protection against BVD virus.
Blood serum titers to BVD were detected at the time initial vaccinations were made, indicating that calves in this investigation had experienced natural infections to BVD virus and had developed some immunity before the vaccination sequence began.
PI-3
A steady increase in blood serum titer to PI-3 virus was detected in the control animals
indicating that PI-3 virus was present in the calves in advance of the vaccination
program. It would also appear that the stress of handling and crowding resulted in rapid
and extensive spread of the PI-3 virus among all animals involved. This would result in a
consistent titer increase among vaccinated and unvaccinated calves. Results obtained for
PI-3 virus demonstrate that it is a virus that spreads rapidly throughout all calves
brought together and that by the end of the six week study period all calf groups had
developed strong antibody titers.
Summary: To obtain maximum antibody levels to the three viral strains tested would require administering an initial vaccination to IBR and PI-3 followed by a booster vaccination two weeks later. And in the case of BVD virus, maximum antibody production would be obtained by giving an initial vaccination for BVD followed by a booster vaccination at three weeks. While this would provide the best protection it is impractical to handle cows and their calves so often. The best alternative is to use a trivalent vaccine (IBR, BVD and PI-3) giving an initial vaccination and following it with a booster vaccination two weeks later.
If one is to establish and maintain maximum blood antibody titers to IBR virus it will be necessary to follow one initial vaccination with IBR vaccine with booster vaccinations at six week intervals, which is impractical. The PI-3 virus is everywhere in the young calf and when they are subjected to the stress of vaccination, handling and crowding there is an extensive spread of this viral agent. The infection under stressful conditions results in the establishment of high blood serum antibody titers by six weeks following the initiation of the stressful period.
References:
I. A. Schipper, D. G. Landblom, J. L. Nelson, V. Anderson, R. Danielson and T. Stromberg.
1984 Optimum vaccination time for feeder calves. North Dakota Agriculture Experiment
Station, Dickinson Branch, 34th Livestock Research Roundup, pp. 38.