Administering a well-planned vaccine program is the most cost-effective health investment a beef producer can make, according to Mark van der List, BVSC, MPVM, senior professional services veterinarian for Boehringer Ingelheim Vetmedica, Inc., based in Davis, Calif.



In killed or inactivated vaccines, the pathogen for the target diseaseis contained in the vaccine but is no longer living.Modified live vaccines, on the other hand, contain living organisms that have been altered to reduce the virulence of the disease-causing pathogen. While still alive, these organisms have been rendered non-virulent by specific vaccine manufacturing techniques.  “A return to virulence in MLVs is possible but extremely rare,” says van der List. 


 To obtain an appropriate immune response from killed vaccines, these products usually containadjuvants, which are additional compounds included in the vaccine. Examples of adjuvants include oil, saponins and aluminum hydroxide. These substances help stimulate the immune system to recognize the killed organism in the vaccine. To obtain an adequate immune response from a killed vaccine,van der List says initially two shots of the same killed vaccine, spaced three to eight weeks apart, are required. Yearly boosters then are recommended

The veterinarian says the advantages of killed vaccines include:


MLVs, on the other hand, offer the following advantages:

  •  A stronger,cell-mediated immune response, plus the initial vaccination usually requires only one dose to infer immunity.  However, because a small percentage of animals may not respond to a vaccine on a given day, it is recommended to repeat the vaccine at a later date.

“Using MLVs in pregnant cows is possible with some approved MLV vaccines, if the same vaccine was previously administered prior to breeding.  But this requires vigilant recordkeeping,” notes van der List.“If the health and vaccination history of a pregnant female is unknown, do not use MLV vaccines,” he says,adding that MLV vaccines also should be used no closer than three weeks prior to breeding. This is especially important in heifers that may not have been vaccinated before.

The one-shot advantage of MLVs is especially convenient for beef cow-calf enterprises that may have limited access to animals at certain times of the year.  Van der List cautions, however, to vaccinate prior to any expectation of disease challenge and preferably not when the animals are highly stressed.



