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Long-Term Immune Response of Beef Heifers Injected
with Either a Single or Multiple Dose Clostridial Toxoid
M. S. Gadberry, 1 T. R. Troxel, 1 D. L. Kreider, 2 P. Widel, 3 and I. Nicholson 3
Story in Brief
The objective of this experiment was to evaluate the long-term immune response of weaned heifers vaccinated
with either a single or multiple dose clostridial toxoid. Heifers (427 ± 63 lb) were randomly assigned to receive either
a one-time injection of a 2-mL vaccine (Alpha-7, A7; n = 15) or the injection on days 0 and 28 with a 5-mL vaccine
(Ultrabac 7, UB7; n = 15). All injections were administered subcutaneously in the neck region using the tented technique.
Serum samples were analyzed for Cl. chauvoei (CC) agglutination titers and antitoxin units for Cl. perfingens
type C (CPC) and D (CPD), Cl. novyi (CN), Cl. septicum (CSE) and Cl. sordellii (CS) on d 0 and every 28 d through d
112. Resulting titers and units lacked normality and were therefore transformed to a natural logarithm before statistical
analyses. Agglutination titers of CC as well as antitoxin units of CPC, CPD, CN, CSE, and CS did not differ (P > 0.10)
between the treatment groups before vaccination on d 0. Clostridium chauvoei titers, CPD and CN antitoxin units of A7
heifers were higher (P < 0.05) than UB7 heifers on d 28. No differences were detected for CPC, CSE or CS. At d 56,
CC titers, CPC, CN and CS antitoxin units were higher (P < 0.01) in UB7 heifers than in A7 heifers. Antitoxin units did
not differ between treatments on d 56 for CPD or CSE. Day 84 CPC and CS antitoxin units remained higher (P < 0.01)
for UB7 heifers than for A7 heifers. By d 112, differences between treatments were only detectable for CPD with UB7
heifers having a lower antitoxin unit than A7 heifers. Alpha-7 invoked a greater immune response by d 28 for CC than
UB7; however, the second injection of UB7 increased immunity for CC beyond A7 by d 56. At the completion of the
trial, d 112, A7 and UB7 levels were similar.
Introduction
Some clostridial vaccines require revaccination 4 to 6
wk following the initial treatment. In reality, however, many
cattle producers fail to gather their cattle for revaccination.
With many stocker cattle grazing programs and feedlot feeding
programs lasting 110 to 180 d, long-term single dose
clostridial protection would therefore be very beneficial. The
objective of this experiment was to evaluate the long-term
immune response elicited by either single or multiple dose
toxoid.
Materials and Methods
Thirty weaned stocker heifers (427 ± 63 lb) were randomly
assigned to receive injections of either Alpha-7 (A7, n
= 15) or Ultrabac 7 (UB7, n = 15, SmithKline Beecham
Animal Health). Ultrabac 7 is labeled for 5-mL injections
with revaccination in 4 to 6 wk and uses an aluminum
hydroxide adjuvant. Both products protect beef cattle against
Cl. chauvoei (CC, blackleg), Cl. septicum (CSE, malignant
edema), Cl. novyi (CN, black disease), Cl. perfringens types
C (CPC) and D (CPD), and Cl. Sordellii (CS) (Veterinary
Pharmaceuticals and Biologicals, 1995-96). The heifers that
received Alpha-7 (d 0) were administrated one 2-mL injection
while the heifers that received Ultrabac 7 were administrated
a 5-mL injection on d 0 and 28.
Blood was collected via jugular venipuncture from
each heifer immediately before Alpha-7 or Ultrabac 7 injection
(d 0) and on d 28, 56, 84, 112, 140, and 180. Blood samples
were placed in crushed ice immediately after collection.
Serum was harvested and stored at -20°C until assayed.
Agglutination titers were determined for Cl. chauvoei by the
serum agglutination test modified from Claus and Macheak
(1972) and Troxel et al. (1997). Antitoxin units were determined
for CPD and CS by the antitoxin neutralization test as
described by USDA:APHIS:VS (1993) and Troxel et al.
(1997) and by USDA (1998), respectively. Antitoxin units
were determined for CPC, CN, and CSE by the antitoxin neutralization
test as described by USDA:APHIS:VS (1985) and
Troxel et al. (1997), USDA (1999) and British
Pharmacopoeia (1993), respectively.
Statistical Analysis. Heifers served as experimental
units. Clostridium chauvoei was measured in microagglutination
titers whereas the other clostridials were measured as
antitoxin units. Therefore, the term “titer” will be used to
denote levels of the immune response for all clostridials. The
1 University of Arkansas Cooperative Extension Service, Little Rock
2 Department of Animal Science, Fayetteville
3 Boehringer Ingelheim Vetmedica, St. Joseph, MO 64506-2002
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