Use TLC with MLVs

Use TLC with MLVs

Vaccinating cattle is too expensive, time-consuming and labor-intensive to do it incorrectly.

Many veterinarians recommend modified live vaccines (MLVs) because they generally are less expensive than killed vaccines; are administered in smaller doses; and are capable of stimulating a longer and more comprehensive immune response. 

But the live, viral organisms in MLVs also tend to be fragile and vulnerable to mishandling. Incorrect storage, exposure to sunlight and delayed administration all can reduce or even eliminate the effectiveness of an MLV, cautioned New Mexico State University Extension Animal Scientist Manny Encinias. He advises the following measures to ensure MLVs are adequately protected to deliver the intended live dose of modified virus when they reach each calf:

Read labels carefully. Be sure to administer the vaccine according to its prescribed dosage and injection method.

Check the expiration date. Don’t take a chance on expired products.

Keep them cool. Whether you’re buying them locally or via mail-order, be sure vaccines are cool when you receive them. Refrigerate until use, and store them in a chute-side cooler until administration. Do not freeze, however, as freezing will destroy them.

Protect from sunlight. Ultraviolet light will kill the viruses in most MLVs, so do not leave vials or syringes in open sunlight on tailgates, dash boards or chutes. Again, a portable cooler is your best bet for protecting them.

Mix only a 30-minute batch. Reconstitute only as much vaccine powder as you will use in 30 minutes. Even properly handled MLVs will lose their effectiveness shortly after mixing.

Swirl gently.  After the diluent is added to the freeze-dried powder, do not shake the solution vigorously. Instead, gently swirl it until all of the powder has dissolved.

Prevent contamination. Never insert a used needle to draw reconstituted vaccine out of a working bottle. Using a clean transfer needle is an inexpensive way to prevent contamination.

Disinfect equipment properly. While cleaning needles and syringes is desirable, do so with boiling water only.Cleaners and disinfectants such as soap, bleach, chlorhexidine acetate, alcohol or iodine will kill the viral particles in MLVs.


Boehringer Ingelheim Animal Health has produced a highly informative You Tube video that also explains effective handling and protection of MLVs.

Taylor Leach
Wed, 07/03/2019 – 14:04


Dairy (General)
Veterinary (General)
Herd Health


Dairy (General)
Veterinary (General)

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Noble Research Institute
Source: Dairy Herd