Metaphylaxis with tildipirosin did not inhibit effectiveness of an experimental monovalent vaccine of live, attenuated Mannheimia haemolytica administered intranasally to dairy calves

  • Scott Nordstrom Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Michael Bolton Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Kevin Hill Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Tim Parks Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Mani Vaidyanathan Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Geert Vertenten Merck Animal Health, 35500 W. 91st St., DeSoto, KS 66018
  • Kelly Lechtenberg Midwest Veterinary Services, Inc., Oakland, NE 68045
Keywords: bacterial vaccine, Mannheimia, interference, tildipirosin, immunization, lung lesions, bovine respiratory disease model

Abstract

The objective of this study was to evaluate the effect of tildipirosin on the efficacy of a concurrently administered experimental vaccine against Mannheimia haemolytica. The experimental vaccine was developed for intranasal (IN) administration and contained the same live, attenuated, streptomycin-dependent Mannheimia haemolytica, at the same titer as in commercial product(s). Eighty-eight 14-week-old Holstein or Holstein-cross male calves from a single source were randomly assigned (using a 2 x 2 factorial design) to 1 of 4 treatment groups (22 head per group) as follows: 1) experimental vaccine (VAX) (IN); 2) VAX (IN) + tildipirosin subcutaneously (SC); 3) placebo vaccine (PLBO) (IN) as negative control; and 4) PLBO (IN) + tildipirosin (SC). Seventy days after enrollment, 84 calves were challenged with virulent M. haemolytica. Clinical assessment of each calf was recorded daily after challenge. There was no significant (P > 0.05) effect of any experimental treatment on clinical signs. Seven days after challenge, the calves were euthanized, a percent lung lesion score (LLS) was assigned to each, and samples of lung were submitted for isolation of M. haemolytica. There was no significant (P = 0.51) effect of tildipirosin on LLS for calves vaccinated with VAX or those vaccinated with PLBO; however, VAX resulted in significantly (P = 0.046) lower LLS. Under the conditions of this study, concurrent administration of tildipirosin and IN live, attenuated, streptomycin-dependent M. haemolytica vaccine with the same antigen as used in this study did not interfere with the efficacy of the vaccine.

Published
2020-06-01
How to Cite
Nordstrom, S., Bolton, M., Hill, K., Parks, T., Vaidyanathan, M., Vertenten, G., & Lechtenberg, K. (2020). Metaphylaxis with tildipirosin did not inhibit effectiveness of an experimental monovalent vaccine of live, attenuated Mannheimia haemolytica administered intranasally to dairy calves. The Bovine Practitioner, 54(2), 145-152. Retrieved from https://bovine-ojs-tamu.tdl.org/bovine/index.php/bovine/article/view/8028
Section
Articles