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Vaccine Reactions Are A Sign – for Sep. 6, 2010

* accine reactions are not an uncommon occurrence today with more and more products being given subcutaneously, especially vaccines with oil-based adjuvants. The adjuvants are designed to protect the vaccine and give it a much greater immune response but reactions in the form of lumps are sometimes an expected, albeit undesirable, side effect.

As many pharmaceutical reps tell us, at least you know the vaccine is working. This is true and we need to keep in mind that the same reactions probably were happening with the intramuscular products except it was occurring deep in the muscle where it wasn’t visible. This is where lots of grisly scarring in the muscle cuts was occurring. So from a beef quality assurance standpoint there has been a huge improvement with almost all the vaccines going subcutaneous.

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

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

Dull, bent dirty or burred needles increase the likelihood of causing an infection or more trauma. This needs to be watched. Change needles when they are damaged and every 10 or so animals. You can feel when they are getting dull. Change them then.

In my opinion the steel, thick-walled needles with the cleaning wires should be outlawed as they give the impression they can be cleaned and reused. They shouldn’t.

If you are seeing large swellings from vaccinations that subsequently abscess, your technique is definitely in question.

I have seen some wrecks occur when vaccinating in the rain. The moisture seems to wash dirt into the needle hole or the process itself takes in more dirt. So try to avoid vaccinating during inclement weather. This doesn’t necessary cancel out the benefit of the vaccine. The infection starts after the vaccine is absorbed so in all likelihood there has been a response. It is another matter when the conditions are too cold, or too hot. Frozen or overheated vaccine will be ineffective and 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 animals can be vaccinated in places like behind the elbow so if there is a reaction it won’t be noticeable.

I have never heard of these vaccine reactions being a problem at an auction sale. In fact the argument could be made that if you see a reaction lump you can be assured this particular stock are being vaccinated. To me, that indicates good management.

In winter they become like a brand and disappear under the hair. At slaughter these lumps are somewhat adhered to the hide and in almost all cases come off with the hide. The underlying meat in not effected in any way so there are no trim losses. We all know if the lumps were a concern buyers would discount for them and that is not the case, at least if it has happened I have never heard of it.

A few other tricks to avoid reactions:

Don’t vaccinate through manure. If the multi-dose gun is hard to advance you may be too shallow and giving the vaccine intradermally, between the skin layers. You want to definitely give the product subcutaneously (under the skin) where 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 over time (baseball size or larger) they have likely abscessed and may need to be lanced and flushed.

If you are giving several vaccines give them in the same location on each animal, leaving at least 10 or so centimetres between each shot. Use opposite sides of the neck if possible. That way, if there are lumps you can assess which vaccine is involved or who gave the vaccine. Sometimes tweaking your injection technique is all that is required.

Certain genetic lines of cattle are more reactive which is why certain herds will have a higher incidence of reactions than others to the same vaccine. Cattle do not appear to get any more sensitive over time to repeated vaccinations but if they react once they commonly will react again so you may see several of these same reactions over the life of the animal.

Please accept vaccine reactions as a normal occurrence but one that should be investigated with your veterinarian when the incidence becomes too large or when abscesses appear. The good news is you can rest assured the vaccine is working and offering protection.

The future may see needleless vaccination or oral or intranasal vaccines which should eliminate these lumps.

About the author

Contributor

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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