Animal Health Matters: Is your refrigerator ready for cattle-working season?

Russ Daly
Special to the Farm Forum

Cattle chute greased up and working smoothly? Check. Broken board repaired on the alleyway? Check. Syringes located and lubed up? Check.

Cattle producers everywhere will soon go through similar “pre”-preconditioning checklists. The time for processing and vaccinating calves is coming upon us quickly. The concept of vaccinating calves while they’re still on pasture, prior to the stress of weaning, has become a hallmark of bovine respiratory disease prevention.

The success of this work depends on much more than the simple act of getting the dose of vaccine into the calf. Making a vaccination a true immunization means the calf has to sufficiently respond to an efficacious vaccine.

That last part is pretty much taken for granted, isn’t it? An efficacious vaccine. Of all the preparations made to work calves, making sure our vaccine is good isn’t on our list. After all, if the vaccine wasn’t effective, the USDA wouldn’t have approved it for use and the vaccine company wouldn’t be selling it, right?

Right. But what’s happened to that vaccine since it left the factory? It turns out there are many ways we can screw up a good product before it gets put into the calf.

Simplified, vaccines consist of two things: the germ or parts thereof (which are modified or inactivated so they don’t cause the illness they’re designed to prevent) and a carrier. The calf’s immune system responds to the vaccine germ’s specific framework of protein molecules. If those proteins have disintegrated or otherwise become messed up, the desired response won’t happen.

What destroys or degrades proteins? The same things that affect ground beef or eggs in your kitchen: high temperatures, light, and time. Vaccines, whether killed or modified-live, can be put in the same category as those protein-based groceries. If they’re not stored in cool dark conditions, their proteins will degrade to the point where the calf’s body won’t be able to recognize them and mount a sufficient immune response. Vaccine labels specify the need to be stored at temperatures between 36 and 45 degrees F.

I’d venture there’s not a cattle producer reading this that doesn’t store their vaccines in a refrigerator. But ... is that refrigerator doing what it’s supposed to, or is it just another one of those things we take for granted?

If your operation is like the one I grew up with, the refrigerator designated for cattle vaccine storage is essentially an afterthought. We used an ancient CO-OP brand machine in my grandpa’s basement, long since banished from the kitchen upstairs. It kept things cool to the touch, so we figured it was doing the job.

What we had no clue about was whether “cool to the touch” was cool enough. If that refrigerator was running at 50 degrees, our vaccine likely had lost potency. If some of the vaccinated calves broke with pneumonia a couple weeks later, it was likely chalked up to the weather or something else — the old fridge was never suspected as the real culprit.

It’s never been easier or cheaper to check whether your vaccine refrigerator is doing the job. Digital thermometers are readily available; high-low versions can easily record the highest and lowest temperatures in the fridge since their reset button was pushed. Get one today and put it in your vaccine refrigerator. They’re not expensive; some (for use in medical refrigerators) even have a bottle-like probe that simulates temperature inside the vaccine vial.

While too-high temperatures are obviously problematic, the opposite condition is just as bad. If refrigerators run too cold and freeze the vaccine, toxic compounds can form in the vaccine carrier liquid (particularly in killed vaccines) that could harm a vaccinated calf.

Also consider where your refrigerator “lives.” If it’s out in an unheated barn subject to environmental temperature changes, check its performance at different times of the year. Maintaining a cool temperature might be easy for the old fridge during fall and winter but does it keep up in the summertime?

Readjusting your refrigerator’s thermostat is the obvious first step when you determine it’s not running in the right range. Sometimes however, the fridge might be beyond adjustment. In that case, purchasing a new one shouldn’t be looked at as an expense, rather as an investment in the health of your animals.