Many reasons for vaccine changes

There are many difficult decisions to be made when changing the brand or manufacturer of a vaccine line. 


The first thing producers must do is determine what diseases they will be vaccinating against, whether they use a modified live, killed or combined program and how effective they think their program was originally. This will help them and their herd veterinarian determine where to come in with different products. 


Of course, this is based on the assumption that the previous vaccines were bought, stored, handled and administered properly and timely to all necessary cattle in the herd. 


There are several reasons why a herd health veterinarian may decide to change lines, and only one of them might be the product’s effectiveness. 


Other reasons are availability, cost, dosage formulation, number of doses per bottle and the service provided by the pharmaceutical company.


I have known clinics that changed trade names simply because of the route of administration. 


If two vaccines are equal, the one that is approved to be given subcutaneously may be a more desirable route and supports Beef Quality Assurance.


Newer products sometimes protect against a broader range of bacteria or viruses, which makes them more desirable. Vaccines that provide greater protection in fewer shots may also be more desirable.


More shots simply mean more labour and stress on the calves. The intranasal route eliminates the needle but may have a shorter duration. These are all important decisions. 


It’s important for producers to read the fine print so that they know which vaccines do what. Most pharmaceutical companies have pretty good spread sheets that indicate which vaccines protect against which diseases. 


It is important to pay close attention to this because vaccines can offer similar protection and yet one organism may be missing. This is where it best to consult with a veterinarian in case there are differences in coverage. 


The next decision is whether producers can continue boosting the same way they have in the past. Just because they have changed vaccines does not necessarily mean they need to start a vaccine program all over again. 


In fact, the opposite is the case.


Vaccines stimulate the body to 
produce antibodies or protection against a specific disease. Adding a different vaccine should booster the previous vaccine response, as long as immunity exists and the diseases are the same in the new vaccine. 


Boostering with a comparable product should work as long as the previous vaccination program has worked well and producers trust the protection that it is giving them. Label directions must be followed. 


It might be necessary to start over if new stock has been acquired that has a questionable vaccination history or if a year has been missed, which means that is now two years between vaccinations.


Other reasons for starting over include missed vaccinations be-cause animals escaped from the chute, dosage that wasn’t calculated or automatic syringes that didn’t work properly. It is likely that an additional organism (virus or bacteria) will need to be boostered the first time if it has been added into the program. 


The bottom line is that the new vaccine should provide proper protection if the previous one gave protection and all the antigens (organisms) are the same. 


Boostering may be needed if new protection has been added, but these are all good questions to ask a veterinarian so that gaps are not created in the new vaccination program.

Roy Lewis works as a technical services veterinarian part time with Merck Animal Health in Alberta.