Getting the most out of your vaccination program

The bovine Ontario Animal Health Network is a group of veterinarians that meet regularly to discuss bovine animal health. During a recent meeting, one of our veterinarians recounted a conversation with a producer who had expressed frustration with the lack of success they were having with an intranasal vaccine in their veal cattle. The vet went to check out the current vaccine package and found it sitting on top of the fridge—in a nice warm spot. Although unintentionally, the producer had probably set things up for that vaccine to fail.

Vaccines, when used properly, will provide protection from disease challenges from viruses and bacteria. When we go to the expense, time, and effort to vaccinate cattle, the last thing we want to do is compromise the success of the program by storing or handling products in a way that will diminish their efficacy.

So, let’s work through a few steps to take with vaccines to ensure their efficacy is the best we can expect from the product.

Date of expiry

Starting with when vaccines are purchased, the first action is to check the expiration date and make sure the farm can use the volume before that date. Veterinary practices and distributors keep on top of the inventory to ensure a sufficient time to expiry, but if a farm is purchasing a large amount at once, the expiry might be up before that number of cattle are vaccinated.

Transport

We want to ensure refrigeration from the time the vaccines leave the vet clinic to the time they are administered to cattle. Ideally, vaccines should go in a cooler with ice packs for any car rides they may be taking. Car temperatures quickly become warm or cold and all vaccines have a safe temperature zone for storage, usually two to eight degrees Celsius, that they need to be kept within. We don’t want vaccines to get too warm or freeze while they sit in the car, or their effectiveness will be lost.

Refrigeration

Vaccines should always be kept refrigerated. Individual product labels will have the safe temperatures listed. By organizing according to expiry date, we can ensure earlier expiration dates are used first.

We also want to make sure the fridge used to store vaccines is in good working order. Keep a thermometer in the fridge to make sure the temperature is not fluctuating. A study from England of fridges on livestock farms found that the majority of fridges in the study failed to keep stored livestock vaccines within the recommended storage temperature range of two to eight degrees Celsius consistently. It’s a good reminder to check that older fridges are working properly.

Temperatures can vary within the fridge, so it is best to keep vaccines in the middle where temperatures are most stable. Never place them in the door where they are subjected to fluctuations or against the back where they can freeze.

Freezing risk

Vaccines generally include an adjuvant, an ingredient that helps create a stronger immune response. Freezing can alter the adjuvant making it no longer effective. Even a single exposure to freezing temperatures can destroy vaccine potency. Therefore, avoiding freezing of vaccines either in the fridge or when they are in the barn being used during cold winter temperatures is imperative.

Heat risk

Vaccines become inactivated when exposed to warm temperatures or sunlight. For this reason, they should be used within an hour after removing them from the fridge. Only mix/draw up enough for what can be delivered in that amount of time and return to the fridge for another batch later. This is particularly important when using a vaccine that comes in a tray of individual doses. Leave the tray in the fridge and only take enough for the number of cattle to be vaccinated imminently.

Re-cooling a vaccine exposed to a warm temperature will not restore its effectiveness and any vaccines left out of the fridge should be disposed of and replaced.

Delivery

A new sterile syringe and needle should be used for mixing, drawing up, and administering vaccines to avoid contaminating the vaccine bottle. Two-part vaccines that come with a diluent should only be reconstituted with the diluent provided. After injecting an animal, do not put the same needle back into the vaccine vial. Although disposable syringes are preferred, some producers may choose to use reusable syringes. If doing so, the syringes must be thoroughly cleaned. The best method is to clean syringes right away before any material dries in them with warm soapy water. Separate the syringe and plunger and thoroughly rinse all detergent away, then air dry on a clean surface. Remnants of soap or disinfectant can inactivate vaccine when the syringe is used again.

It’s important to check the label and be sure each animal receives the recommended volume. We also want to make sure all staff are familiar with the product and how it should be delivered. For example—whether the product is an injectable or intranasal vaccine.

For many vaccines, the entire contents must be used once opened or mixed to protect product potency. Check the label if this is the case with the vaccine you are using before putting it back in the fridge.

Finally—safely dispose of used vaccine vials and syringes in appropriate medical waste and don’t forget to record the animals vaccinated and the withdrawal times.

Disease prevention strategies such as vaccination are far superior to treating ill animals—let’s make sure our practices make the most of them.

References available upon request.

The Bovine Ontario Animal Health Network is a group of veterinarians and specialists working in government, university research and laboratory, and in beef, dairy, and veal practice who meet regularly to monitor and discuss disease trends in Ontario. Our goals are to facilitate coordinated preparedness, early detection, and response to animal health and welfare in Ontario. For our recent reports or more information visit www.oahn.ca.