Vaccines must be properly handled

Vaccination programs have become a common part of bio-security efforts for livestock operations.

Following best practice vaccination protocols controls disease, minimizes antibiotic use, improves production and decreases death or losses from abortion.

Veterinarians can help producers develop protocols that minimize or eliminate vaccination problems such as leukotoxic effects from gram-negative vaccines, allergic reactions, vaccine site infections and poor immune response from a myriad factors.

There are two types of vaccines: those for viral infections and those for bacterial infections.

The bacteria come in two forms: gram positive and gram negative.

Gram positive include clostridial diseases and anthrax. They don’t produce leukotoxins.

Gram negative bacteria are most of the other bacteria we vaccinate against, such as respiratory pathogens and E. coli. They are used for scours prevention and to control E. coli mastitis in dairy herds.

These bacteria can produce leukotoxins, and some are worse than others. We should avoid using too many of them at the same time.

The leukotoxic effect causes rapid breathing and foaming at the mouth and can lead to abortions and death. Cattle that do recover may be in chronic poor health and susceptible to other diseases.

Do not vaccinate with more than two of the most powerful leukotoxin-producing bacteria at the same time.

We see more leukotoxic effects in dairy herds because they use more gram negative vaccines. As well, dairy cows are under the production stress of milking.


Some genetic lines seem more susceptible to the leukotoxic effect.

Other factors that increase the odds of having a leukotoxic reaction include parasitism, poor nutrition (a lack of micro minerals) and the potential of having slight acidosis (grain overload).

Vaccines designed to combat E. coli, vibrio and salmonella (seen more in the United States) are at the top of the list for leukotoxin-producing severity. Histophilus, foot rot, pinkeye and pasteurella (pneumonia) vaccines are in the middle group, while leptospirosis vaccines are in the least leukotoxin-producing category.

The effects are cumulative so producers who need to give lots of gram negative vaccines may be encouraged by their veterinarian to spread them out by a week or more.

Vigorously shaking vaccines when they are rehydrated can release more leukotoxins than when they are swirled. These leukotoxins also increase as the vaccine ages and if it becomes too hot or cold.

Clearly it is important to properly handle vaccines. Question your veterinarian if you need help sorting out vaccination protocols. They will be aware which vaccines result in the leukotoxic stacking effect described.

Vaccines can have adjuvants to enhance the immune response, and they sometimes trigger allergic reactions. This is more common with killed bacterins and killed vaccines rather than with the modified live vaccines.

Always have a bottle of epinephrine as well as an antihistamine and a dexamethasone (steroid) on hand to treat allergic reactions if advised by a veterinarian. Allergic reactions usually happen soon after the injections. The animal shows rapid breathing, swelling or puffy eyes, depending on the degree of allergic reaction.

Treatment may need to be repeated a few times.

It is a good practice to walk through recently vaccinated cattle to check for reactions. They are rare, but my experience is that when they do come it is in multiple cases.


The good news is that most animals with allergic reactions can be saved if caught in time.

Vaccine reactions can turn into infections. To avoid infections:

  • Change needles frequently.
  • Make sure the syringe has been cleaned before starting.
  • Don’t vaccinate through manure.
  • Use the proper sized needle.
  • Don’t vaccinate in the rain because the water washes dust and debris into the needle hole.

Most investigations into abscessation following vaccination discover that the animals were vaccinated in a rainstorm or shower.

I realize vaccinations must be finished once they have been started, but watch the weather forecast to determine the best, dry day on which to process. This may prevent these vaccine infections.

Poor immune response depends on stress levels, nutrition, exposure to organisms and parasitic burden.

A good vaccination program can be overwhelmed by poor management and exposure to lots of organisms.

Vaccination does not guarantee a disease-free herd.

Use it as an adjunct to good management to increase productivity.

Select the right vaccines by consulting with a veterinarian.


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