Vaccination continues to play a central role in dairy herd health programs, helping producers manage disease risk, protect productivity, and support long-term herd performance.
At its core, vaccination works by training the immune system to recognize and respond to disease. When done effectively, it builds immune memory, allowing animals to respond faster and more effectively when exposed to pathogens.
However, vaccines are not a one-size-fits-all solution. Their success depends on timing, product selection, and how well they align with herd-specific risks.
Vaccination is about managing risk—not eliminating it
Vaccines act as a form of insurance. They reduce the likelihood and severity of disease, but they do not guarantee complete protection.
In most cases, vaccines help prevent clinical illness rather than infection itself. If animals face high pathogen loads or immune stress, disease can still occur—even in vaccinated herds.
That makes vaccination just one part of a broader herd health strategy that includes nutrition, housing, and overall management.
Understanding the types of vaccines
Dairy producers typically work with two main types of vaccines, each with different strengths.
Modified live vaccines (MLVs) contain weakened versions of a virus or bacteria. These vaccines stimulate a strong immune response, often with fewer doses, because they replicate in the animal without causing disease.
Killed (inactivated) vaccines, on the other hand, do not replicate. They require a booster to build strong immune memory but are often used in situations where live vaccines may not be appropriate.
Some protocols use combination products that include both types. In these cases, part of the protection develops quickly, while other components require follow-up dosing.
Why timing and boosters matter
A common gap in vaccination programs is assuming that one dose provides full protection.
In reality, many vaccines—especially killed products—require a booster to be effective. The first dose introduces the immune system to the pathogen, while the second builds lasting protection.
Even with modified live vaccines, revaccination can help reduce the number of animals that fail to respond initially. In a typical herd, a single round of vaccination may leave a portion of animals unprotected. A second dose can significantly improve overall herd immunity.
Core diseases still drive vaccination decisions
Most dairy vaccination programs focus on diseases that pose the greatest risk to health and production.
These often include:
- Respiratory viruses such as IBR, BRSV, PI3, and BVD
- Reproductive diseases linked to IBR, BVD, and leptospirosis
- Clostridial diseases such as blackleg and tetanus
These diseases can impact milk production, fertility, and overall herd performance. In many cases, they also open the door to secondary infections, increasing treatment costs and labour demands.
No two dairy herds have the same protocol
While core vaccines provide a starting point, there is no universal program that fits every operation.
Disease pressure, housing systems, animal movement, and management practices all influence risk. For example, herds with higher levels of animal turnover or group housing may face different exposure challenges than closed herds.
Because of this, vaccination programs should be tailored—not copied.
Work with your veterinarian to build a program
Producers should work closely with their herd veterinarian to design and adjust vaccination protocols.
A strong program considers:
- Disease risks specific to the operation
- Timing relative to calving, breeding, and grouping
- Product selection and handling
- Booster schedules and compliance
Veterinarians can also help evaluate vaccine performance and troubleshoot when results fall short.
A foundation for herd health
Vaccination does not replace good management—but it strengthens it.
When paired with strong nutrition, biosecurity, and housing practices, vaccines help reduce disease pressure and support more consistent production.
For dairy producers, the goal is not just preventing illness. It’s building a resilient herd that can maintain performance even when challenges arise.
