Do’s and don’ts of handling fall calf vaccines
Pre-weaning vaccinations are a well-established part of cow-calf producers disease prevention strategies.
These vaccines’ effectiveness at preventing disease depends upon many different factors. We depend upon the calf’s immune system to respond to the vaccine appropriately. But the calf depends on us to deliver a fully potent dose of vaccine. When we vaccinate a calf are we robustly stimulating his immune system, or are we injecting a worthless syringeful of liquid under his skin? The answer largely lies in how we handle the vaccines. This time of year is a good time to get reacquainted with some of the do’s and don’ts to consider when handling these important products.
First, some things to do. Do understand the differences in handling modified-live (MLV) versus killed vaccines. In order for an MLV vaccine to work, the germs inside need to be viable and able to multiply inside the animal. If they die prior to being injected, there’s not enough of them to stimulate immunity. Killed vaccines are somewhat more accommodating to handling errors than are MLV vaccines, but even killed vaccines need to be protected from the big three threats to vaccine viability: age, heat, and light.
Do mark the syringes used for MLV vaccines. If the syringes are mixed up and you draw up MLV vaccine into a syringe containing leftover killed vaccine, the MLV vaccine will probably be inactivated. Marking the MLV syringe with a piece of electric tape is one handy way to keep them straight.
Do put a new needle on the syringe before drawing up vaccine from the bottle. A needle that’s been used on an animal – even if it looks clean – is contaminated. Sticking a used needle in the vaccine bottle will spread that contamination to the whole bottle.
Do check your refrigerator temperature. You may find that your “old reliable” fridge doesn’t keep vaccine in the right temperature range (35-45 F). Over longer storage times, temperatures too high or low can reduce vaccine potency.
Do continue to protect vaccine during the job. Chute-side, keep the vaccine at refrigerator temperatures and out of sunlight. Coolers with ice packs are good for this purpose. Think about syringes too – a small cooler tipped on its side on the working table can help keep the vaccine in the syringe cool and out of sunlight.
And now for some don’ts. Don’t let vaccines get above refrigerator temperature – ever. This means from the time you take it out of the display cooler at the vet clinic, to the ride home in the pickup, to the refrigerator, to the… you get the picture.
Don’t rely on vaccines to work after their expiration date. While vaccines don’t magically disintegrate at midnight on its expiration date, understand that the vaccine company has assured us the vaccine will remain potent only up until that date. After that, no one really knows.
Don’t get overly germ-a-phobic about your syringes. Clean syringes are good – don’t get me wrong. But using disinfectants inside a syringe can inactivate MLV vaccines, even if just a trace of the disinfectant remains. There are methods for cleaning syringes with hot distilled water that work well.
Don’t buy large bottles of MLV vaccine unless you can work through the cattle in a timely fashion. The underlying issue is that once mixed, a MLV vaccine is only viable for a matter of hours, even kept sufficiently cool. A good rule of thumb is to not mix up more MLV vaccine than you can use in an hour.
If it takes you all afternoon to work your 50 calves, buy five 10-dose bottles rather than one 50-dose bottle, and mix them as you go.
Don’t expect to return vaccines after you’ve purchased them. During the time the vaccine has been out of their hands, the veterinarian or supplier can’t guarantee that the “cold chain” has been maintained sufficient for the vaccine to be resold. After all, you wouldn’t want to buy vaccine that was just returned by someone who left it in a hot pickup the prior afternoon.
Following these tips will help ensure your calves get the most out of that syringeful of vaccine this fall. Your local veterinarian is a great resource for further questions about vaccine handling.
Russ Daly, DVM, is the Extension Veterinarian at South Dakota State University. He can be reached via e-mail at[email protected] or at 605-688-5171.
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