Occasionally cattle react to vaccine. An allergic reaction can be mild and local, with swelling at the injection site. But if the animal goes into anaphylactic shock, it can be serious and even fatal.
Vaccines contain antigens that are foreign to the body. The goal is for the body to recognize them as foreign and to develop antibodies to combat these antigens in the future. On rare occasions an animal may develop an acute allergic reaction to a foreign substance. Reactions can range in severity from harmless lumps to systemic shock with fluid in the lungs and sudden death.
Dr. Tim Nickel, bovine technical services veterinarian with Boehringer Ingelheim, says vaccines are designed to stimulate the immune system, but sometimes this results in hyper-stimulation.
“This is an individual reaction, similar to people with allergies. Some cattle are more sensitive to that particular antigen,” he says. It could be due to a genetic component, he adds. It could also involve environmental exposure, especially at a young age, as the immune system is developing.
Dr. Dorothy Erickson, manager of veterinary services for cattle at Zoetis, says some factors that contribute to a reaction can be prevented or controlled. How a person handles and administers a product and stressful events that occur while vaccinating can make a difference, she says.
“Other things, like genetic predisposition, are things we generally can’t control. Certain individual animals are more predisposed to reactions,” Erickson says. “This is why we sometimes see a cluster of reactions within a certain herd or genetic line of animals.”
The most common vaccine reactions are due to the antigen itself, but can also be due to the carrier or adjuvant. Killed vaccines tend to be a little weaker at stimulating the immune system than a modified-live vaccine so adjuvants are added to boost immune response and make the vaccine more effective.
“We probably saw more reactions to some of the older adjuvants than we see today with modern adjuvants, but we still see some reactions associated with these, and they are most commonly used in killed vaccines,” says Nickel. Of the killed vaccines, most reactions occur with the clostridia products (the seven-way and eight-way vaccines), he adds.
Often these reactions are local swelling rather than anaphylactic reactions. Nickel says they often see a lump at the injection site, especially as beef quality assurance programs recommend subcutaneous injections at the neck.
In the past, most vaccines were injected into muscle. That meant lumps weren’t as large or visible, Nickel says.
“There was also more tissue to absorb it and it would resorb more quickly,” he says. “You might not have seen much of a lump, in that location, but it could result in scar tissue and affect meat quality.”
Subcutaneous lumps are more visible and last longer. Nickel has seen some that are five centimetres or more in diameter, but in most cases they’re not very painful, he says.
But location makes a difference with subcutaneous lumps. “If it is close to the shoulder, just a few inches up the neck, the swelling and pain may hinder forward movement of that shoulder and the animal will be stiff and lame for a few days,” says Nickel.
The best location is further up the neck, where there’s not much movement, he adds. The headgate might affect the location, so Nickel suggests a chute with a neck extender, which gives access to the entire neck.
Nickel says when it comes to calls about reactions, lumps and swelling are the most common. Generally, several animals are affected — as much as one-third to half the herd. But the reactions are usually temporary, he adds.
“Without any treatment these lumps disappear after a few days. If they are painful, we may treat the animal with a non-steroidal anti-inflammatory like Metacam to relieve pain and tenderness, but most of the time you don’t need to do anything,” Nickel says.
Producers do need to figure out whether the lumps are abscesses rather than vaccine reactions. An abscess will eventually break open and drain pus. The abscess is caused by a dirty needle, Nickel says, not the vaccine.
“This can happen if a person keeps using the same needle on too many animals, or injects through a dirty hide or wet skin,” he says. “If it’s raining when people vaccinate, we see a few more abscesses. If the hair is wet there is more risk of taking some contamination in with the needle.”
If there’s manure on the planned injection site, a producer should pick a different spot, Nickel says. If the animal has manure on both sides of the neck, a producer might have to inject subcutaneously under the loose skin behind the shoulder or elbow.
“The downside of injecting in these locations is if you get a lump, it could be more tender or painful,” says Nickel. “This is probably better, however, than an abscess at the injection site. It’s the lesser of two evils. You probably can’t wash the animal if the neck is covered with manure, and even if you did, this would create a wet hide and some risk for contamination. You are probably not going to run these cattle through again, so you need to go ahead and vaccinate.”
Once in a while cattle get hives after vaccination, though they’re more common in horses. They’re usually temporary, but Nickel does recommend consulting with a veterinarian if an animal develops hives.
“In some cases they might be treated with a non-steroidal anti-inflammatory drug to bring them down a bit faster, or treat with dexamethasone if the cow is not heavily pregnant,” he says. Giving steroids can make a cow abort.
Anaphylactic reactions are rare, and some producers will never see one. But they can turn fatal quickly, says Nickel.
“Those animals may drop in the chute immediately after the injection. If it is that rapid, there is nothing you can do to reverse the reaction and save the animal,” he says.
After cattle have been vaccinated, monitor them closely for at least one to two hours. “Walk through them and observe them for any signs of reactions,” says Erickson.
Erickson says that anaphylactic reactions generally occur within 10 to 20 minutes of injection. Signs of anaphylaxis include rapid breathing, muscle tremors, swelling around the face (this may be seen as puffy eyelids), or drooling, she adds. The animal might seem uncomfortable.
If the reaction is severe and progresses, the animal will collapse and be unable to get up. It will go into shock and die, unless treatment is administered immediately, she says.
“One thing I always recommend is having epinephrine on hand, at the chute,” says Nickel. Epinephrine is an antidote for reactions. It’s something a person hopes to never have to use, but if it’s needed, it’s needed right now.
“If you have to run to the house to get it, it’s often too late,” says Nickel. “If you have to drive to a veterinary clinic it’s almost always too late.”
Epinephrine only has a shelf life of 18 to 24 months, depending on how long it sat on the shelf before the rancher bought it, so producers should check the expiration date, Nickel says. Using it if it’s a year or two past its expiration date is not ideal, but probably better than doing nothing, if nothing else is on hand.
“It might become less effective, but would not be harmful,” says Nickel. “The molecule breaks down over time and this is why it has a shorter shelf life, because it is not as stable as some products.”
Erickson says it’s important to monitor an animal after an epinephrine injection for at least an hour. If the animal seems to be improving within 15 to 30 minutes, it will probably recover. But if the animal is not improving or declining, it could use another injection. An animal’s breathing is the most important clue, she says.
“The thing that ultimately kills them when they go into shock will be fluid in the lungs, and subsequent suffocation,” she says.
Erickson suggests talking to a veterinarian before vaccinating about how to administer epinephrine and what the proper dose would be.
“I recommended putting a piece of tape on the bottle, writing the dose on it, so it will be easily visible,” she says. “It’s easy to forget from year to year, especially if you don’t have to use it very often.”
Other things your veterinarian may recommend for treatment include steroids or antihistamines to decrease swelling in the airways and lungs. Have some of these medications on hand in case of serious reactions.
Anaphylactic and local reactions can’t always be prevented.
“It is always wise to use good hygiene, however, when vaccinating, and use transfer needles when rehydrating modified-live virus vaccines,” says Nickel. That eliminates the risk of sticking a dirty needle into the bottle when mixing it, which would contaminate the whole bottle. Use a new, clean needle when drawing the vaccine out.
Change needles often when giving injections, says Erickson, for cleanliness, and to avoid tissue damage. A dull needle is more likely to cause damage.
“It’s also important to select appropriate needle size for the injection and make sure you are giving the product according to label,” says Erickson. “Some are labelled for subcutaneous use and others for intramuscular use. And some give you the option for route of administration.”
Another important factor is how many vaccines you are giving at the same time, or concurrently with other products.
“Some products may interact with or negatively impact others and you might not want to give them all at the same time,” says Erickson.
She recommends working with a veterinarian on vaccination schedules and protocols, and letting the vet know about other treatments that will be done at the same time, such as parasite treatment or vitamin or mineral injection.
Store vaccine properly, and don’t let it freeze or warm up too much.
“Don’t put the bottle on the dash of your pickup to keep it from freezing,” says Nickel. Many vaccines are light-sensitive, he explains, and may break down, which might result in more reactions than you’d otherwise expect.
Keep a thermometer in the refrigerator to make sure the temperature is staying within the ideal range. Store vaccine in the fridge’s centre so it is not affected by the freezer compartment or the door opening.
Check expiration dates. “Sometimes you have vaccines left over from last year, but make sure they have not expired by the time you use them. You may not see reaction associated with out-of-date vaccines, but you may have less efficacy than expected,” Nickel says.
Nickel suggests buying vaccine in bottle sizes you’ll use up, and discarding bottles if they’ve been open for a long time or had a needle in them. Otherwise, contamination risk climbs and there’s more chance of the vaccine breaking down. This applies to killed vaccine, too, as the air will oxidize the contents, says Nickel.
“Those are situations where sometimes we see more reactions — generally just the lumps. We might not expect anaphylactic reaction, but there is more chance for reactions to occur when you keep vaccines that have been opened,” he says.
If an individual animal has a serious reaction to a certain vaccine, consult with your veterinarian before you give that same vaccine to that individual again.
“Once the immune system is sensitized, it is more likely you will see the same reaction again, and usually worse, the next time you give that vaccine,” he says.
Depending on disease risk, you might not vaccinate that animal again, says Nickel. If it’s a very serious disease that the animal is likely to be exposed to, you could vaccinate but keep epinephrine on hand to treat immediately if needed.
“There is also the option of trying a different brand for that particular vaccine, in case it might have been the carrier that the animal reacted to,” he says. “Unfortunately, we generally don’t know whether it was the carrier or the antigen that caused a reaction.”
Reducing stress during handling can help reduce reactions in some situations, says Erickson. That means using low-stress handling techniques and avoiding vaccinating cattle in very hot weather.
“Cattle can handle cold weather better than they can handle heat, especially the breeds we see here in Western Canada,” she says. If it’s going to be a hot day, try to vaccinate in the morning, she adds, or postpone until a cooler day.
Nickel says producers should report any serious reactions to their veterinarians, who will report those incidents to company technical service veterinarians.
“We investigate, report and monitor these incidents,” he says. “Having the serial number and expiry date from the vaccine can assist us in these investigations.”