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Vaccine reactions are normal — to a point

Proper injection practices help avoid infection, contamination

Noticeable reactions to a vaccine injection are becoming more common, as more vaccines are now given subcutaneously and especially with vaccines using oil-based adjuvants.

The adjuvants are designed to protect the vaccine and give a much higher immune response, but reactions in the form of lumps are an expected albeit undesirable result.

As many of the pharmaceutical reps will tell us, at least we know the vaccine is working.

This is true and we must keep in mind the same reaction was probably happening before with the intramuscular products, it’s just the reactions happened deep in the muscle where it was not visible to us. This is where lots of the gristle (scarring in the muscle cuts of meat) would occur. So from a beef-quality assurance standpoint there has been a huge improvement with almost all the vaccines going subcutaneous.

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Common reactions

Most of the lumps regress with time, or a small egg-sized lump is left which is a granuloma or basically a lump of scar tissue. You will find more reactions with the bacterins like blackleg and the other killed vaccines as they generally use the oil-based adjuvant. The modified live vaccines generally use sterile water as the liquid for reconstitution, so the reaction is much milder.

More reactions can occur if the nutritional status of the herd is low especially in the three trace minerals copper, zinc and selenium. If there is a high percentage of large reactions nutrition should be checked as well as the producer’s administration technique.

Dull, bent, dirty or burred needles increase the likelihood of introducing infection or causing more trauma. This needs to be watched. Change needles when they are damaged and at least after every 10 or so animals. You can feel when they are getting dull and it is time to change. In my opinion the steel thick-walled needles with the cleaning wires should be outlawed as they give the producer the impression they can be cleaned and reused. This should not happen.

What about technique?

If you see large swellings from vaccination, which subsequently abscess, the technique of administering the shot needs to be looked at. I have seen some wrecks occur when cattle are vaccinated in the rain. The moisture seems to wash dirt into the needle hole or the process itself takes in more dirt. Try and avoid vaccinating in inclement weather. The infection starts after the vaccine is absorbed so in all likelihood there has been a response. Keep the vaccine protected from the elements, as frozen or overheated vaccine will be ineffective and it might be denatured leading to more vaccine abscesses.

The egg-sized reactions are of no concern to the animal but are simply a blemish noticed more in this country in the summer when the hair is slicked off. Purebred show or display animals can be vaccinated in places like behind the elbow so if there is a reaction it won’t be noticed.

I have never heard of vaccine reactions being a problem at auction sales. The argument could be made that at least you can see these particular stock are being vaccinated — that to me relates to good management.

In the winter the lumps become like a brand and disappear under the hair. When slaughtered these lumps are somewhat adhered to the hide and in almost all cases come off with the hide not affecting the underlying meat in any way so there are no trim losses. We all know if they were a concern, buyers would discount the price. I haven’t heard of that happening.

Further advice

Also when vaccinating, don’t vaccinate through manure. If a multi-dose gun is hard to advance you may be too shallow and giving the vaccine intradermal (between the skin layers). You want to definitely give the product subcutaneously (under the skin) and it should be very easy to inject. Use the smallest-gauge needle that still allows you to inject it quickly (16-18 gauge).

If the lumps get large (baseball size or larger) over time they most likely are abscessed and may need to be lanced and flushed.

To check technique if giving several vaccines give them concisely in the same location leaving at least 10 or so centimetres between injection sites. Give the shots on the opposite sides of the neck if possible. That way if there are lumps you can assess which vaccine is involved and/or who administered the vaccine. Sometimes tweaking your technique is all that is required.

Certain genetic lines of cattle are more reactive which is why certain producers will have a high incidence and other farms have almost no reactions with the same vaccine. Cattle do not appear to get any more sensitive over time to repeated vaccinations. but if reacted once they commonly will react again so you may see several of these same reactions.

Accept vaccine reactions as a normal occurrence and investigate with your veterinarian if the incidence gets too high or if abscesses are created. Rest assured the vaccine is working and offering protection. The future may see needleless vaccination or oral or intranasal vaccines given which will eliminate this lump issue.

About the author

Columnist

Roy Lewis is an Alberta-based veterinarian specializing in large-animal practice. He is also a part-time technical services vet for Merck Animal Health.

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