Depending on your vaccination program, you may use both modified-live (MLV) and killed vaccines throughout the year. Made with a virus or bacteria that has been weakened to ensure the pathogen does not cause the disease once injected, MLV vaccines are not stable in solution and have been stabilized by freeze-drying. A sterile liquid diluent or specialized killed vaccine must be added to activate the MLV vaccine. Killed vaccines consist of a virus, bacteria or toxin that has been killed with heat or chemical agents. Adjuvants are added to these solutions to help stimulate immunity. Killed vaccines typically require two or more inoculations to generate the most effective response. However, to preserve any vaccine’s efficacy, it is critical to adhere to the following handling and storage strategies.
Temperature and sunlight
Vaccines need to be stored between 35ºF to 45ºF at all times, and maintaining consistency within this temperature range is critical. Do not allow a vaccine to freeze. Due to changes in the structure of the adjuvant, frozen killed vaccines can have extreme and even deadly consequences if injected. Extreme heat and exposure to ultraviolet (UV) light can also denature both MLV and killed vaccines, so extra precautions should be taken.
When purchasing vaccines, bring a cooler with icepacks to the vet supply store so you can maintain the product’s temperature while transporting. Keep the product in a refrigerator that’s closely monitored for temperature; shop and garage refrigerators are often not as effective at maintaining consistent temperatures as those indoors.
If purchasing vaccines from an online distributor, order early in the week to avoid weekend shipment delays. On arrival, be sure the product is still cool when removing it from the packaging. If it is warm or has expired, do not use the vaccine – contact the supplier and return the shipment. Arrange to be available when the shipment arrives so that you can safely transfer it into a refrigerated environment and avoid allowing the package to sit outside for an extended period of time.
Expiration and timing of use
It is not advisable to use expired products, so always check the vaccine’s expiration date before use, even when purchasing it over the counter. Some ranch supply stores may keep outdated product on the shelf if it hasn’t sold, so double check the expiration date before purchase. Store products that will expire first in the front of the refrigerator and those with later expiration dates toward the back.
Once reconstituted, MLV vaccines are only effective for a short period of time, even if mixed before the product’s expiration date. It is best to use mixed MLV vaccines within two hours. Do not refrigerate MLV products after they’ve been mixed and expect to reuse them at a later date, as they are unstable in solution form. Purchase only the amount you need and dispose of any leftover product. Killed vaccines may be reused before the expiration date if handled and stored properly. Always record the lot and serial number of vaccines you purchase in case of vaccine failure or other problems.
Many vaccines, especially killed products, require multiple inoculations to achieve optimal results. The product label outlines timing of use, so become familiar with each product’s specific requirements and always use them according to label instructions. Like antibiotics and other injectable products, vaccine labels also indicate the product’s withdrawal period, typically 21 to 60 days. Be sure to abide by the withdrawal period to prevent drug residues.
Chute-side tactics
The environment during processing is one of the biggest concerns regarding vaccine storage and handling. Exposure to changing weather, temperature and sunlight needs to be addressed.
Consider utilizing a chute-side cooler with icepacks to store both vaccines that are still in the bottle and any product that has been drawn into a syringe. Cut holes in the cooler that are large enough to store the barrel of a multi-dose syringe to keep product in the barrel out of sunlight and changing temperatures between uses. The cooler itself is effective for storing bottles that are being drawn from and extra bottles during processing. Single dose syringes can be kept in these coolers as well.
No matter the type of vaccine, expect seven to 14 days for cattle develop immunity, and keep in mind that vaccines are not 100 percent effective, even if stored and handled appropriately. Vaccinating healthy, stress-free cattle that are on a solid plane of nutrition will provide the best immune response. 
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Libby Bigler
- Colorado BQA Coordinator
- Colorado State University
- Email Libby Bigler
PHOTO: To provide the best immune response, vaccines still in the bottle or that have been drawn into a syringe shouldn't be left exposed to the elements. Staff photo.
